Final Report Summary - CLUNA (Clustering phenomena in nuclear physics: strengthening of the Zagreb-Catania-Birmingham partnership)
Executive summary:
Experimental nuclear physics is one of the top research activities at the Ruder Boskovic Institute (RBI), the largest Croatian research center in science and applications. The RBI nuclear physics group has strong link with the research group at the University of Zagreb (UoZ). RBI scientists perform experiments at the RBI Tandem accelerator facility and at the top EU experimental facilities in collaboration with the prominent EU research groups in the field, including partners from the Laboratori Nazionali del Sud INFN (INFN-LNS), Catania, Italy and the Nuclear Physics Group from the University of Birmingham (UoB), UK. With CLUNA we strengthened scientific relationships, the exchange of know-how and sharing of experience between RBI, UoZ, INFN-LNS and UoB partners in the research field of our common interest, focusing on the studies of nuclear molecules and other areas at the forefront of research for new phenomena in nuclear physics.
This was achieved by:
(i) reinforcement of RBI experimental capabilities through the upgrade of the local experimental facility,
(ii) exchange of personnel between partner institutions, hiring and training of young staff at accelerator facilities,
(iii) organization of workshops and short term training events, dissemination of project results to specialists and general public.
In particular, the existing nuclear physics experimental end station, including detector system, at RBI Tandem Van de Graaff accelerator was upgraded. New low-noise high-power electricity system and gas target system for use of the helium and hydrogen gas were designed and built. The upgraded silicon detector array for detection of charged particles was accompanied with the detection system for neutrons. Both detection systems were coupled together in the data acquisition system to enable simultaneous detection of neutron and charged particles. Data acquisition system was completed and commissioned. Procedures for production of new ion beams for nuclear physics experiments, including 3He, 4He, 9Be, 10,11B, and 18O, have been adopted and as a result those beams are now routinely available. Water and gas isotopically enriched in 18O required for production of the 18O beam, 4He and 3He gas for production of related isotopic ion beams were purchased to sustain future production of related ion beams. Upgraded research infrastructure for low energy measurements at RBI and complementary facility at LNS for intermediate energy measurements through this partnership contribute to the increase of research opportunities for even broader European experimental nuclear physics community.
Three outstanding graduated students were employed, now all being supported as PhD students by local funds. Extensive visits of junior and senior staff between the partners were organized to exchange know-how and to share experience. Workshop on "Inverse kinematics measurement technique for gas targets" was held in April 2010 at INFN-LNS. Two planned RBI workshops, on elastic and inelastic scattering as a toll in spectroscopic studies, and on nuclear molecules, were merged into one longer workshop, held in April 2011. Practical training at the SPIRAL facility of the GANIL laboratory was held in autumn 2010. This event provided excellent opportunity for the RBI/UoZ researchers to work in international environment at top class international laboratory, enlarging their research experience. The new RBI detection system functioned well in complex experimental conditions applied in these trainings.
Project Context and Objectives:
The overall objective or goal of CLUNA project is to strengthen relationships, to exchange the knowhow and to share experience between Ru?er Bokovi? Institute (RBI), Laboratori Nazionali del Sud INFN (INFN-LNS), School of Physics and Astronomy, University of Birmingham (UoB) and Faculty of Science, University of Zagreb (UoZ) in the research of common interest. The focus is on studies of nuclear molecules and other related topics at the research forefront for new phenomena in nuclear physics.
The project particularly aims to boost scientific and technological research potential of the RBI experimental facility for common RBI-LNS-UoB-UoZ studies with low energy ion beams. This includes an upgrade and renewal of the existing nuclear physics experimental end station at RBI Tandem Van de Graaff accelerator to improve its capabilities for collaborative research in low energy nuclear physics. Important activities in realization of the objectives are the exchange of personnel between partner institutions, hiring and training of young staff at accelerator facilities and organization of workshops and short term training events.
In particular, specific objectives of CLUNA are:
(1) To upgrade the existing nuclear physics experimental end station, including detector system, at the RBI Tandem Van de Graaff accelerator and production of new beams at the accelerator facility.
This includes:
(i) Removal of the existing scattering chamber to the position more appropriate for new proposed experimental activities (including modeling of the ion beam optics, changes on the beam line, new collimating system, changes on vacuum system), and building of new vibration-free chamber stand.
(ii) Upgrade of the chamber in order to allow experiments with gas target for inverse kinematics measurements (including development and assembly of new flanges, new valves for pumping and venting operations, control of the gas flow, development and assembly of entrance window). Development of the helium gas target as well as production of new beams at the facility would enable measurements of resonant (in)elastic scattering in the inverse kinematics, a powerful method already applied worldwide and at the INFN-LNS facility. Collaboration with the INFN-LNS and UoB groups is essential, since they have large experimental experience in the field.
(iii) Renewal of the noise-free high power electricity system with proper grounding at the experimental end station, which will allow use of the recently acquired detector and electronics setup (with much larger number of detectors and electronic units than in the former setup) required for new experimental activities.
(iv) Acquisition, assembly and commissioning of several fast neutron detectors and associated electronics, including building of detector mounts, and coupling of the neutron detectors to the existing detection system for charged reaction products. This new detector system, via detection of neutrons from nuclear reactions, will make possible new research activities for institutions involved in the proposal and will significantly increase research capabilities of the RBI facility, which are presently limited to the detection of charged reaction products. It also includes development of adequate fast neutron shielding for neutron detectors and chamber's Faraday cup.
(v) Upgrade of the existing detection system for charged reaction products with new large area thin (20 - 35 ?m) silicon detectors for detector telescopes (particle identification) and acquisition of adequate preamplifiers for these detectors. This upgrade will extend detectable energy range of charged reaction products. Upgraded detection system including neutron detectors will be compact and transportable for measurements at different experimental sites including INFN-LNS.
(vi) Continuous and increased usage of 3He and 4He beams, and production of new beam species of interest in nuclear cluster studies: 9Be, 10,11B and 18O. In addition to standard heavy ion beams from the EN Tandem accelerator, the 3He and 4He beams have been used in Zagreb since the commissioning of ion source for helium negative ions in 2004. Nevertheless, several improvements and upgrades of the experimental end station for nuclear reaction studies are needed to further explore usability of these beams.
(vii) Reinforcement of the RBI group human potential by hiring new young researcher(s) who will be involved in the upgrade and later use of experimental end station. Young researcher(s) will acquire knowledge and experience from senior researchers of all four partner institutions and will be involved in all activities of the RBI group. Strengthening of RBI group with young researcher(s) will allow more frequent and efficient use of the upgraded experimental end station. Hired young researcher(s) will start postgraduate studies during the first year of employment. Usual Croatian practice for hiring of young researchers imply that research group finds graduated student first and then apply for his/her position. It usually takes a year or even longer to employ new PhD student. Through this project we would require funds for covering young researcher expenses for period before official employment at RBI by Croatian Ministry of Science, Education and Sport (MSES). Once employed by MSES, young researcher will continue his/her employment at RBI until he/she obtains PhD degree, and possibly later as a research associate.
(2) To strengthen the collaboration between RBI, UoZ, INFN-LNS and UoB through the exchange of knowledge and experience relevant to the field, leading to future common experiments and knowledge transfer at international level
This includes:
(i) Exchange of knowledge and experience in the field of "Data acquisition and front end electronics" between the UoB and RBI/UoZ staff, including training of young researcher(s) from RBI at UoB. Staff at UoB has valuable experience with electronics and data acquisition for nuclear reaction measurements, which is very important in upgrading of the RBI experimental capabilities.
(ii) Exchange of knowledge and experience in the field of "Inverse kinematics measurement techniques" between the INFN-LNS, UoB, UoZ and RBI research personnel, including knowledge transfer from the INFNLNS to RBI on production and maintaining of gas targets, and training of young researcher(s) from RBI at INFN-LNS experimental site.
(iii) Exchange of knowledge and experience in the field of "Experimental techniques employed in cluster studies" between RBI, UoB, UoZ and INFN-LNS through specialized workshops and training events at RBI facility.
(iv) Short term specialized training of RBI researchers at one of the European top research laboratories for knowledge sharing in experimental techniques for nuclear structure studies and work of the RBI staff in an international environment with researchers from partner institutions.
(3) Dissemination of knowledge and project results
This includes:
(i) Participation of the RBI research staff at international conferences on nuclear structure and reactions. RBI researchers will present there their new results obtained in collaborative work with partners from INFN-LNS and UoB.
(ii) Some of our collaborators from other European institutions (Laboratori Nazionale di Legnaro Italy, University of Surrey UK, University of Caen France etc.) have also shown interest for experiments at RBI facility. Presentation of upgraded RBI facility and its capabilities for new experimental activities to broader European nuclear physics community through personal contacts would lead to new collaborative experiments at RBI, increasing the number of international users of the facility and will increase RBI international reputation.
(iii) RBI staff will work on popularization of science in general and specifically nuclear physics through presentations of upgraded nuclear physics end station to general public during the RBI "Open Days" and lectures for general public, organization of seminars on nuclear physics at RBI. For educational purposes, the facility will be used in the nuclear physics undergraduate and graduate courses as well as for the experimental part of the BSc, MSc and PhD thesis. Staff of other partner institutions will work accordingly at their local environment.
(iv) upgraded and renewed experimental end station at RBI will be presented at a new web site, as well as all other activities of RBI group and RBI-UoZ-LNS-UoB collaboration.
INFN-LNS is one of the two accelerator laboratories for nuclear structure and reactions research in the Italian national network for Nuclear Physics research (INFN) and is one of the top Italian institutions for nuclear physics research.
Nuclear Physics Group from the University of Birmingham is one of the most active UK research groups in nuclear physics with high scientific impact.
Researchers from INFN-LNS and RBI have been working in strong collaboration for 30 years and performed many experiments at INFN-LNS, other EU experimental facilities and several experiments at the RBI accelerator facility. Collaboration between RBI and Birmingham group started in 2000 and resulted so far with more than 30 experiments at international facilities. Through this project we will strengthen partnership between these four institutions for benefits of all partners: RBI will improve its research capabilities in nuclear physics and will serve as a competitive research centre for low energy nuclear reaction studies at European level, INFN-LNS will increase number of users of its intermediate energy facilities and will increase its value as the research centre at European level, UoB will have two new sites for complementary types of nuclear reactions measurements and UoZ will have upgraded local facility for research and educational activities. Moreover, tighter partnership of these four already successful groups will form highly competitive collaboration at the international level which will propose and perform future experiments at INFN-LNS, RBI and other European accelerator facilities.
By reinforcing the existing research potential of the RBI nuclear physics end station through this project, the facility will be able to continue and extend its traditional light nuclei collisions studies and will provide services to the collaborators in a more efficient way. The realization of proposed project will also open the possibilities to offer new research activities to the WBC region and to the broader European nuclear physics community, as well as to strengthen RBI presence at the European Research Area in this specific research field.
Specific project objectives are accomplished through work packages. The first work package (WP1) groups together all project management activities, and the last one (WP7) deals with the project dissemination activities. WP2 to WP6 are technical work packages, i.e. they group together activities leading to implementation of the scientific and technical objectives.
- Work package 1 (WP1): Project Management
- Work package 2 (WP2): Improvements of experimental capabilities for nuclear structure research at RBI
- Work package 3 (WP3): Young researcher employment and education
- Work package 4 (WP4): Data acquisition system and front-end electronics
- Work package 5 (WP5): Measurement techniques for inverse kinematics reactions
- Work package 6 (WP6): Experimental techniques in nuclear cluster studies
- Work package 7 (WP7): Public awareness and dissemination of project results
Project Results:
Main S&T project results/foreground are presented for each technical work package (WP2 to WP6).
Work package 2 (WP2): Improvements of experimental capabilities for nuclear structure research at RBI
The objectives of WP2 are:
(i) to upgrade and renew the existing nuclear physics experimental end station at the RBI Tandem accelerator for nuclear physics measurements in order to increase its experimental capabilities;
(ii) to increase the performance of existing detection system at the RBI nuclear measurement end station in order to increase its usability for nuclear structure and reaction studies; and
(iii) to assure long term delivery of 3He and 4He beams and to make available new ion beams at the Tandem facility.
The old experimental end station had limited capabilities for nuclear structure and reactions studies, but was already in use for some simpler collaborative research activities, primarily in collaboration with the INFN-LNS research group. Part of work on its upgrade, including acquisition of new detector system for charged particle detection, started several years before the CLUNA beginning. Yearly available local funding was very limited, but during the years large part of required equipment was collected. The CLUNA funds were used to finalize and commission the experimental setup.
New low-noise high-power electricity system
New low-noise high-power electricity system was designed and built at the new chamber position. The experimental end station requires electricity for normal operation: vacuum elements like mechanical and turbo-molecular pumps or mechanical elements of the scattering chamber like lid opener use electricity. Additionally, all kind of detectors, including different types of silicon detectors for charged particles, and all electronic units for signal processing from detectors, require electricity (as example for bias voltage) for their operation. Particular care should be paid to electricity source for detectors and associated electronics, because electric signals from the detectors are very small (in the milivolt range) and could be disturbed by electronic noise from various sources. To reduce a noise and increase performance of the detectors and associated electronics chain (preamplifier, spectroscopic and timing amplifiers, logic units, analog-to-digital converter), their electricity source has to be well isolated from all other power systems and properly grounded. Initial power system used at the experimental end station was not properly separated from the rest of the building electricity system and its power was enough only for up to ten electronics chains. This is adequate for the old small silicon detector system used at the experimental end station before, but is not enough powerful for the new silicon detector array composed of large number of silicon strip detectors. For this reason, a new low-noise high-power electricity system was designed and built at the experimental end station. In the first year of the CLUNA project experimental end station was moved to the new, more appropriate position for the new experimental activities. So, the work on the new power system was performed during this movement of the end station. Actually, the work on this task started before the start of the CLUNA project due to its importance for our experimental program. Significant part of the equipment for this task (15 kW transformer, cables, small electrical equipment and materials) was acquired before the CLUNA start and these costs were covered by our national grant. The most of the work was performed in the first months of the CLUNA project and the work costs of the RBI employees were covered by the CLUNA project funds. The new system has enough power (15kW) for use of detector system with 250 signals and associated 250 electronic chains. Its noise level is reduced to the lowest possible. The setup was tested twice using our new detection system, and the system is now in full operation.
Gas target system at the experimental end station
Initially, the RBI experimental end station was suitable for experiments with thin foils as target only. Introduction of the gas target measurements, particularly suitable for low energy beams provided by the RBI Tandem Van de Graaff accelerator, presents a large increase of experimental capabilities of the facility and opens the new research topics on nuclear structure and nuclear astrophysics research at RBI. Of particular interest are hydrogen (proton and deuteron) and helium targets. Main experimental technique with gas targets is resonant scattering in inverse kinematics regime, when heavy beam particle is scattered off the light target particle detected in the measurement.
Originally, in the project proposal only helium gas target was considered. The work on the design, purchase of required hardware, and on building of the gas target system was finalized during the first year of the project. New valve was mounted on the scattering chamber for gas inflow. The scattering chamber was isolated from the vacuum in the beam lines with entrance window which was designed, manufactured and tested. Various designs of the window, the range of the window size and thickness as well as various materials for the window were tested before the final setup was accepted and commissioned. For low intensity ion beam measurements Mylar window is behaving well and it is preferred material due to very low cost. However, measurements with high intensity ion beam require much stronger, but also very expensive, HAVAR window. Introduction of the entrance window required replacement of the existing collimator system with the new one. Beam optics for the new collimator was calculated, and collimator was designed and manufactured.
During the work on this task, the RBI group developed new research program on nuclear astrophysics and started new research project managed by European Science Foundation under the EuroGENESIS program (part of the Eurocores program) funded by Croatian National Foundation for Science and High Education (Nacionalna Zaklada za znanost i visoko obrazovanje - NZZ). It came out that for nuclear astrophysics studies hydrogen gas target would be highly desirable. Also for nuclear structure studies, our main research topic, hydrogen gas target (in the first instance deuterium gas) would be very useful. The essential difference between helium and hydrogen target is that hydrogen is flammable, which requires additional security measures in handling gas. We found out that simple changes on the gas target system and small additional investment could enable the use of hydrogen gas in the target system. We therefore redesigned the gas target system. New pumping system for gas outflow was purchased and installed. All required work was performed by the end of July 2009, with a small delay compared to the original planning.
Silicon detector array
Essential step in increasing research capabilities and capacities of the RBI facility in nuclear structure and reaction studies was completion and commissioning of the detection system for charged particles. Core of the detector system was acquired before the start of the CLUNA project: five large area thick (500 µm) position sensitive strip detectors and four large area thin (50 µm) quadrant detectors, as well as preamplifiers, amplifiers, analog-to-digital converters (ADC) and most of other electronics for 160 signal channels.
Neutron detector array
For further enlargement of the RBI experimental facility capabilities and capacities for low energy nuclear physics research, commissioned large silicon detector array for detection of charged particles was accompanied with new detection system for neutrons. Neutrons, neutral particles building atomic nucleus, are reaction products in many processes important in nuclear physics and nuclear astrophysics. Availability of the neutron detection system makes possible a new sort of experiments designed to study these processes at the RBI accelerator facility and other facilities in Europe at which we regularly perform experiments.
Works on tasks related to neutron detector array were delayed regarding to original work plan due to delay on commissioning of the silicon detector array and the data acquisition system. The reason for this delay was the above mentioned hardware failure at the RBI Tandem Van de Graaf accelerator facility, which put our experimental end station out of use for six months. Work on acquisition of the neutron detectors started in the second half of 2009. Detailed study on available neutron detectors on the market was performed. Extensive discussions within the project partners and our collaborators from other institutions with experience on neutron detection (we appreciate great contribution from our collaborators from the GANIL and LPC Caen France) was taken for decision on the detection system properties most suitable for our research activities.
Work performed on DAQ setting and achieved results
Very important step in increasing research capabilities and capacities of the RBI facility for nuclear structure and reaction studies was completion and commissioning of the detection system for measurements of nuclear reaction products. In the measurements, analog electric signals from various detectors produced by detected reaction products are processed in electronics. The electronics role is double-fold:
1) to produce amplified and reshaped useful electric signals,
2) to produce logic signals related to detected particles which are required for selection of interesting events from background and other non-relevant events.
These logic signals are processed in various logic electronic units resulting in trigger signal which signalize detection of physically relevant events. Such selection mechanism has to be fast and efficient due to high counting rate of the detection system required to collect significant statistics of interesting events. Obviously, trigger cannot (or can in only very limited number of cases) provide clear online separation of all physically interesting events from background and non-relevant physics, so its main role is to significantly reduce all background/unwanted processes and enable further processing of reduced volume of data. Such accepted signals are then converted to digital values in Analog-to-Digital Converters (ADC) activated by trigger signal. These data are recorded on event by event basis for later offline analysis and extraction of results.
Part of electronics system performing reduction of events, conversion of data to digital form and recording of data is called Data Acquisition system (DAQ). As was the case with other parts of the detection system for measurements of nuclear reactions, core of the DAQ was acquired before start of the CLUNA project: many logic electronics units, VME crate, 6 analog-to-digital converter (ADC) units with 32 channels each, VME processor and ADC control unit. This core makes possible building of the DAQ for processing of 192 signals from the detectors using DAQ software MIDAS (http://npg.dl.ac.uk/MIDAS/) developed at the Daresbury Laboratory in UK.
One of the CLUNA project goals was finalizing and commissioning of the DAQ. The MIDAS software communicates with the VME processor, uploads the operating system into the VME processor, enables settings of the various units in the DAQ and receives and records data from the DAQ to the computer hard disc. Software was originally written for Sun operating system Solaris running on the Sun computers built on SPARC architecture. It was recently modified to work on Solaris operating system on computers with Intel and AMD architecture. There are also versions of MIDAS for other operating systems, like Linux and Microsoft Windows, but the most reliable and highest performance version is still built for Solaris operating system. The University of Birmingham group members have vast experience in running older versions of MIDAS on Solaris SPARC computers connected to VME DAQ systems and their experience and knowledge have been of the prime importance for setting up the DAQ system at RBI. Their support was realized through work package 4.
It was decided to build DAQ on Solaris operating system due to its favourable performance and experience of the Birmingham group. Detailed study of the available hardware options and requirements on computer set by our detection system showed that the best value for money provide Sun server computers built on AMD architecture. The server Sun Fire X4100 M2, computer in the middle class of Sun servers on the market in Croatia, running on the latest version of Solaris operating system, was purchased using national funding. Solaris was reconfigured for the use as DAQ server and the latest version of the MIDAS software for INTEL/AMD architecture was installed and configured.
The final and full test of complete detection system, including silicon detector array, electronics and DAQ, was performed during the workshop held at INFN-LNS Catania in April 2010. Test was done using large detector array with six detector telescopes giving 288 detector signals into the electronics and the DAQ system. The research equipment of our partners from INFN-LNS and University of Birmingham was used together with our equipment. Beam from the Tandem accelerator of the INFN-LNS was used in the test. In this test very complex experimental setup and conditions were applied. The all the components of the detection system were running smoothly, providing final evidence for successful commission of the detection system.
Production of ion beams
Work on production of new ion beams at the RBI Tandem accelerator started according to the plan. The production procedure for the 18O beam was developed during the first project year. Commissioning of the first 18O ion beam was successfully performed in April 2009 and it is now available for regular use. We purchased more material (water and gas) isotopically enriched in 18O required for production of the 18O beam for future research at the RBI accelerator facility.
In order to maintain possibilities for delivery of these ion beams for future research at the RBI accelerator facility, the necessary material was purchased. This includes water and gas isotopically enriched in 18O required for production of the 18O beam, 4He and 3He gas for production of related isotopic ion beams.
The production of the 14C beam has been postponed for future. The reason for this decision is related to the possible future use of the EN Tandem Accelerator as Accelerator Mass Spectrometer (AMS). This is currently the most sensitive method for radiocarbon dating and there is at the moment an interest at the RBI to introduce this technique at the EN Tandem Accelerator. Since radiocarbon dating is based on the use of 14C ion beams, its parallel use for nuclear physics experiments could result with unreliable radiocarbon dating measurements.
To summarize, all the tasks associated with WP2 were successfully completed. As a result, the experimental end station is fully upgraded according to the project description of work, with some additional improvements which required small additional investment. Upgrade and renewal of the existing nuclear physics experimental end station increased its experimental capabilities. The RBI detection system is enlarged with the large silicon detector array for charged particles detection, neutron detector array, associate front-end electronics and data acquisition system. The system is fully operable and in usage for nuclear structure and reaction studies as well as for research in nuclear astrophysics. Availability of helium beams for future research have been secured and new ion beams of 9Be, 10,11B, 13C and 18O are available for experiments at the RBI Tandem accelerator facility.
Total cost of this work package was 196560 ?, 25% more than originally planned.
Work package 3 (WP3): Young researcher employment and education
The objective of WP3 was to strengthen the RBI group human potential for project activities and research. This objective was realized through employment of young researchers and their education for work on CLUNA project and on nuclear physics research.
Activities started in May 2008. The standard procedure for employment of research PhD student at the RBI was followed. Public call for open position was published in the Official Gazzette of the Republic of Croatia "Narodne novine" (see http://www.nn.hr/sluzbenilist/ oglasni/index.asp online) no. 71, daily newspapers "Vjesnik" (see http://www.vjesnik.hr online) on June 20th 2008 and on the RBI official web page (see http://www.irb.hr online). Requirements for the position were: BSc degree in physics, preference for experimental work in nuclear physics, final average mark at graduated studies greater than 4.0 (out of maximal grade of 5.0) candidate should be fluent in English and have affinity for team work in international environment. Duties of the new employee included engagement in all activities of the CLUNA project, particularly in work on renewal and update of the experimental end station at the RBI accelerator facility and associated detector setup, including acquiring of knowledge and experience required for experimental research work in nuclear physics.
We followed the idea to enroll young researcher in postgraduate studies in nuclear physics during the first year of employment. In addition, in order to sustain employment for a period after CLUNA, in parallel with the employment, a PhD student position at RBI would be asked for young researcher from Croatian Ministry of Science, Education and Sport (MSES). In case of MSES approval before the end of the project, another young researcher would be employed, with parallel support request from MSES. Strengthening of RBI group with young researcher would allow more frequent and efficient use of the upgraded experimental end station.
At the beginning of the project implementation we found two outstanding graduated students for this position. On 1st July 2008 Ms. Iva Bo?i?evi? was employed. She graduated physics at University of Zagreb in spring 2008. She was employed on CLUNA project until 31st December 2008. From1st of January 2009 funding for her position was secured by MSES in the LIBI research group at the RBI accelerator facilities, also involved in the CLUNA project.
Therefore, another graduated student, Mr. Lovro Propolec, was employed on 2nd February 2009. In early 2010, coordinator of the CLUNA project re-applied to MSES for PhD student position for Lovro (the first application in 2009 was not approved due to very limited number of positions). Application was approved in late 2010 and Lovro has been employed by MSES on six years PhD student contract, starting from the December 9th 2010.
Lovro significantly contributed to the work on all the tasks of the experimental end station upgrade, work on setting up the data acquisition system and testing of acquired silicon detectors and associated electronics. He was educated and trained by senior RBI and UoZ researchers involved in the CLUNA project on experimental techniques and methods in nuclear structure research, settings and use of silicon detectors and electronics and data analysis. INFN-LNS and UoB researchers transferred their knowledge and experience to him during visits at RBI, during Lovro visits to INFN-LNS and UoB, and on CLUNA workshops and practical training event.
Lovro attended international conference "Nuclear Structure and Dynamics 09" (conference web page is http://www.phy.hr/~dubrovnik09/ online) which CLUNA researchers from RBI/UoZ coorganized (Matko Milin from UoZ was Scientific Secretary, Suzana Szilner from RBI was cochair, Neven Soi? of RBI was member of Local Organizing Committee) in Dubrovnik on May 3rd to 9th 2009. Conference was attended by large number of world class researchers who gave presentations of their contemplate research results. This was excellent opportunity for young researcher to learn about state-of-the-art research in nuclear physics from world experts.
Lovro also attended summer school on nuclear physics by European Summer University "The secrets of the atomic nucleus" in Strasbourg France from June 28th to July 4th 2009 (the school web page is http://esc.u-strasbg.fr/2009/). Summer school was organized with 12 lectures given by world experts in the field, 2 round tables and 3 practical student workshops. Lovro attended practical training on detection of neutrons which was particularly useful in setting up neutron detector array at RBI (WP2).
He attended short training on beam and target production at INFN-LNS accelerator facility (March 15 - 18, 2009), practical training on the use and setting up of the silicon detector array and all associate electronics from preamplifiers to DAQ (April 7th - 12th), and another training on calibration of position sensitive silicon strip detectors and analysis of data collected with such detectors (April 24th - May 2nd). He also attended the workshop held at INFN-LNS from April 13 - 23 2010. More details about the workshop are given in section on WP5. The short practical trainings with equipment were particularly useful for Lovro to increase his level of knowledge and experience and enable higher level of knowledge transfer at the INFN-LNS workshop.
Total cost of WP3 in the project was 58306 ?, 16% more than planned.
Work package 4 (WP4): Data acquisition system and front-end electronics
The objectives of WP4 are:
(i) to strengthen the collaboration between UoB and RBI/UoZ research groups;
(ii) to exchange knowledge and experience on data acquisition and electronics for nuclear reaction measurements between UoB, RBI and UoZ researchers; and
(iii) to help realization of WP2 and WP3. In particular, for WP2 objectives, support is needed in assembly, testing and commissioning of VME data acquisition system and in coupling of the existing detection system for charged nuclear reaction products with a new one for the fast neutron detection and for WP3 is related to education of young researchers.
All WP4 objectives were achieved. Collaboration between UoB and Zagreb group has been enhanced. RBI research staff acquired knowledge and experience required for setup of electronics and DAQ system. Coupling of neutron detector array and silicon detector array into common DAQ setup was successfully realized. It came out that for full realization of the project objectives we needed less exchange visits than planned, because RBI and UoB researchers met regularly for experiments and these occasions were used also for CLUNA activities. For this reason, realized staff efforts and accordingly expenses, were smaller than expected.
Total cost of WP4 during the project was 6711.25 ?, some 30% of the planned funding.
Work package 5 (WP5): Measurement techniques for inverse kinematics reactions
Objectives of WP5 are:
(i) to strengthen the collaboration between INFN-LNS and RBI/UoZ research groups;
(ii) to exchange knowledge and experience on measurement techniques for inverse kinematics reactions using gas target, and on design and assembly of gas targets between research staff from INFN-LNS and RBI/UoZ; and
(iii) to help realization of WP2 and WP3 (education of young researcher).
All WP5 objectives were accomplished. Collaboration between research groups from all the four partner institution is strengthened compared to the situation before the CLUNA project. RBI researchers gained new knowledge and experience. New knowledge and skills were successfully used in realization of WP2 and WP3 tasks.
During the first project year the INFN-LNS staff spent 2.5 person-months, while RBI staff spent 3.5 person-months on the activities of this WP. Costs of this WP in the first year were 7699.57 ?.
In total, during the second project year RBI staff visited INFN-LNS for 79 person-days which include participation of five researchers at the workshop, training of young researcher and visits for knowledge and experience exchange of senior researchers. INFN-LNS staff efforts for this work package in total were 5.5 person-months. UoB staff efforts for WP5 were 0.6 person-month. UoZ staff efforts were 0.5 person-month. Costs of the WP5 were: 12149.07 ? for RBI (includes all travelling expenses to Catania and transport of the equipment for the workshop from Zagreb to Catania and back), 7668 ? for INFN-LNS, 1653.16 ? for UoZ and 1927.27 for UoB.
During the third project year, staff efforts of RBI were 0.75 p-m, INFN-LNS 0.75 p-m and UoZ 0.3 p-m. Costs of the WP5 were 2407 for INFN-LNS and 1199 for UoZ.
Total cost of this WP during the project was 34703 , 17% less than originally planned.
Work package 6 (WP6): Experimental techniques in nuclear cluster studies
The objectives of this WP are:
(i) to strengthen the collaboration between RBI/UoZ, INFN-LNS and UoB;
(ii) to exchange knowledge and experience on experimental techniques for nuclear structure studies between all partner institutions; and
(iii) to help in realization of WP2, WP3, WP4, WP5 and WP7.
Workshop at the RBI
Two workshops were planned at the RBI accelerator facility under WP6, the first one with the topic on elastic and inelastic scattering as a tool in spectroscopic studies, and the second one on nuclear molecules. The first workshop, on the use of scattering measurements for spectroscopic studies of nuclei, was planned to have strong practical component with extensive training of the Ruder Boskovic Institute and University of Zagreb staff at the RBI accelerator facility. It was planned that experienced staff of University of Birmingham and Laboratori Nazionali del Sud transfer their practical knowledge on the use of experimental equipment for measurements of scattering processes with light nuclei to RBI and UoZ researchers. It was planned to concentrate the second workshop, on exotic structure in light nuclei similar to atomic molecules, to analysis techniques of the experimental data resulting with information on nuclei structure and experimental evidence for nuclear molecules in light nuclei. These two workshops were complementary dealing with clustering phenomena in nuclear physics, scientific topic behind the CLUNA project. The Project Management Board proposed and the Project Officer approved to merge these two workshops in one, covering the planned topics of both workshops, including additionally interrelation between experimental technique (measurement of scattering processes, topic of the first workshop) and structural phenomena in nuclei (nuclear molecules, the topic of the second workshop). In this way one combined workshop provided additional added value to the project. Merging of the two workshops gave a chance to attendances to work on both subjects at the same time and easier follow a path from experimental work on measurements, which provide required data, to data analysis and interpretation of experimental results, which finally results with the new scientific information. Initially, the first workshop, one with the practical training requiring ion beams in the RBI experimental chamber, was planned to be performed during the 2nd project year, but due to the vacuum pump failure and six months (Sep 2009 - Mar 2010) unavailability of the beam, we were not able to realize it at that time. This workshop was rescheduled to Sep 2010. In summer 2010 GANIL management informed us that the two experiments in which were involved researchers from the CLUNA project, as well as our CLUNA practical training event (part of WP6) were scheduled for the period from middle September until the beginning of November the same year. For this reason the workshop at Zagreb was postponed to December 2010. Unfortunately, another hardware failure at the RBI Tandem accelerator facility, malfunction of power supply of the switching magnet (one which delivers ion beams to the experimental end lines), hampered realization of the workshop. Power supply of the switching magnet was repaired in January 2011 and the Tandem accelerator facility was back to normal operation by the end of January 2011. Due to the quite short time left until the end of the CLUNA project, merging two workshops in one sounded as good option. Merging has also saved time and funds required for the full realization of the project.
This workshop was organized in the same way as the one at INFN-LNS. It was mainly dedicated, especially the first half of the workshop, to practical work with the research instrumentation, including intensive training on equipment usage in the measurements of the scattering processes. For this training, some research equipment from Birmingham and Catania was required to complete experimental setup based on the RBI equipment. Data acquired from the scattering measurements provide important results on spectroscopy of nuclei which obey the laws of quantum physics: characteristics of the nucleus excited states. Full characterization of the excited states makes possible understanding of structure of the studied nucleus. The second part of the workshop was dedicated mainly to offline analysis of the experimental data, interpretation of the results on nuclear spectroscopy and extraction of the results on nuclear structure from the knowledge of nuclear spectroscopy. Techniques and methods of the analysis were demonstrated on the experimental data collected during the workshop. Experienced researchers from UoB and INFN-LNS, having complementary expertise on various steps in this complex process of acquiring new results on nuclear cluster structure and nuclear molecules, were giving lectures and leading training sessions with the help of senior Croatian scientist with adequate expertise for the considered topic.
This workshop was successfully realized. All RBI equipment was tested in experimental conditions different than the ones in the previous workshop at INFN-LNS and worked well in joint complex experimental setup with INFN-LNS and UoB equipment. RBI researchers, particularly PhD students, collected new knowledge and experience on setting up and running complex measurements, running measurements for spectroscopic studies and the data analysis which results in the new knowledge on nuclear structure.
Practical training at GANIL
The next large event planned in the CLUNA project was practical training of the RBI/UoZ researchers at the radioactive ion beam facility SPIRAL located at GANIL laboratory in Caen, France (see http://www.ganilspiral2.eu/ online). This facility is currently unique facility in the world considering wide spectrum of reaccelerated unstable ion beams of light nuclei and the beams intensity, purity and focusing properties. This event provided excellent opportunity for the RBI/UoZ researchers to work in international environment at the top class international laboratory, significantly enlarging their research experience.
Experimental work with unstable ion beams is largely complementary to the work with stable ion beams due to very different constraints on experimental techniques and methods, and in the same time it is prerequisite for experimental work in contemporary nuclear physics. New knowledge in the field of nuclear physics can be gained only from measurements performed using high quality stable and unstable beams as their results puzzled together provide complete picture of the atomic nucleus. For these reasons, this training event at unstable ion beam facility, unavailable at the RBI and INFN-LNS, was important step towards the full realization of the CLUNA project objectives.
Participation at international conferences
WP6 activities also included participation of the RBI and UoZ research staff at international conferences and workshops on nuclear physics, where they presented results of the research work performed in collaborations with researchers involved in the CLUNA project, as well as on new possibilities for experiments at the RBI nuclear research end station upgraded through the CLUNA project. Attendance of RBI/UoZ researchers to six conferences was planned, but at the end travel expenses for three conferences were covered using CLUNA funds. However, the RBI/UoZ researchers attended some international meetings, schools, conferences and workshops using other funding sources, using these occasions to disseminate results of the CLUNA project and present enlarged research capability and capacity of the RBI nuclear physics research instrumentation.
All the expected objectives of the WP6 were fully achieved: the collaboration between all the four partner research groups is stronger than it was before the CLUNA project, knowledge and experience on experimental techniques and methods for nuclear clusters studies have been spread over all participating researchers, and acquired knowledge and experience have helped in successful realization of all planned activities in other project work packages.
Total cost of the WP6 in the project was 43740 , close to 90% of the planned work package funding.
Potential Impact:
Impact
The immediate impact of the CLUNA project is greatly improved research potential of the RBI/UoZ groups for nuclear physics experimental work. In addition to the improved experimental facility and expertise, the project has a synergetic effect on the scientific cooperation between the project partners and their cooperation with the other nuclear physics groups from Europe. Apart from an increased contribution to existing collaborations, the successful realization of CLUNA provided opportunities to enter new collaborations at both national and European level. The upgraded experimental end station for nuclear physics research at the RBI Tandem Accelerator facility is unique in Croatia and South-East Europe, with large potential benefits to the broader scientific community, to the national and regional universities and wider.
With CLUNA, partnership has been strengthened at several levels with three prominent partner organizations: Universities of Zagreb and Birmingham (UoZ and UoB), and with the Italian National Institute of Nuclear Physics, Laboratory in Catania (INFN-LNS). With all of them RBI had already established cooperation. CLUNA strengthened this partnership, especially through human mobility actions and exchange of know-how. Through CLUNA partnerships between Zagreb and EU groups has been strengthened by more frequent personal contacts, exchange of knowledge and experience between researchers, upgrading of experimental end station at RBI with the aim to serve as research facility for collaboration measurements and via future commonly planned and performed experiments at RBI, INFN-LNS and other European accelerator facilities. Due to overlapping research interest of involved groups and access to upgraded RBI and INFN-LNS facility for all members of the collaboration, partnership between these four research groups will continue after the end of this project. During CLUNA implementation, new partnerships were established with researchers from other R&D organizations, like from University of Huelva in Spain and GANIL and LPC, Caen, France.
All partners benefited from results of this project: RBI obtained more competitive research infrastructure with significantly increased number of external users, INFN-LNS have access to improved low energy accelerator facility and increased number of international users at home facility, UoB obtained a new site for low energy measurements at RBI and additional site for intermediate energy measurements at INFN-LNS, and finally UoZ obtained access to better local site at RBI for research and educational purposes.
RTD capacity and capability at RBI has been upgraded with new researchers employed, training of research staff, improvement of research management, and upgrade of scientific equipment.
New researchers: Three outstanding graduated students were employed. They were nicely incorporated into the RBI nuclear physics research groups. They are all now employed as PhD students on national research grants supported by the Ministry of Science, Education and Sport (MSES). Without CLUNA it would be difficult to attract these young researchers and keep them during the period of uncertainty while waiting for approvals of local funds for hiring new staff.
Training of research staff: Exchange of knowledge, know-how and experience on modern experimental nuclear physics, including measurement methods, interpretation - validation of data, interpretation of experimental data and modeling resulted in a well educated and skilled staff, able to perform complex R&D work required in collaborative projects. Altogether the RBI/UoZ staff spent about 12.5 person-months for training activities at partner organizations and top international research laboratory (GANIL), and staff from partner organizations spent about 10 person-months at RBI and GANIL. Two workshops were held, one at the INFN-LNS and one at the RBI, and one training event at the GANIL Caen, France, resulting with intensive transfer of knowledge and experience. Further, intensive exchange visits program between RBI/UoZ and partners resulted in significantly enlarged knowledge and experience of the RBI/UoZ staff.
Improvement of research management: CLUNA project increased the research management capabilities of the RBI, realized through WP1. Staff from the respective RBI support department assigned to this project visited UoB to exchange know-how and experience in R&D project management. Experience and knowledge on research management acquired both by the RBI researchers and administration during the project implementation are valuable background for future larger projects.
Scientific equipment: the RBI experimental end station for nuclear physics research is fully upgraded according to the project description of work, with some additional improvements which required small additional investment. Upgrade and renewal of the existing nuclear physics experimental end station increased its experimental capabilities. The RBI detection system for nuclear physics research is enlarged with the large silicon detector array for charged particles detection, neutron detector array, associated front-end electronics and data acquisition system. In the enlargement of the RBI experimental capabilities, large part of funds and work has been used for purchase and commissioning of fast neutron detectors. Merging of the neutron detectors with the silicon detector array on improved end station greatly expanded the research topics for future collaborative research. The system is fully operable and in usage for nuclear structure and reaction studies as well as for research in nuclear astrophysics. Availability of helium beams for future research have been secured and new ion beams of 9Be, 10,11B, 13C and 18O are available for experiments at the RBI Tandem accelerator facility. New detection system at RBI is compact and transportable. It can be used for research not only at the local RBI experimental facility, but also at the INFN-LNS accelerator centre and other accelerator laboratories worldwide. The detection system is fully compatible with research equipment of our partners from University of Birmingham and INFN-LNS.
Unique expertise for the region: Enlargement of the capacities for experimental nuclear physics research at RBI significantly improved the scientific and technical infrastructure for this kind of research in the WBC region. Even more of that, after the upgrade of the scattering chamber, renewal of the detection system by inclusion of very thin silicon and fast neutron detectors and development of the new beams, RBI research capacities for nuclear structure and reaction research are competitive with the European small facilities. The RBI experimental end station is the only one of this kind in WBC region. In the broader region, SouthEast and NorthEast Europe covered by the EastWestOutreach Nuclear Physics Network (EWON), the EURONS networking activity of 18 institutions from East Europe, RBI is one of the only six existing facilities which satisfy prerequisites for high quality research (others are Rez, Athens, Debrecen, Warsaw and Bucharest). These facilities are now working together in one of ENSAR (FP7 infrastructure project of European nuclear physics community) work packages.
Reducing brain drain: Increased potentials for high quality experimental and collaborative R&D in the field of experimental nuclear physics increased the desirability by graduate students to join the research activities of the RBI/UoZ group. Students become aware that high quality research can be performed also at Croatian institutions. This helps to reduce the large brain drain from Croatia, improving the national education level, and increase the number of Ph.D. thesis carried out at RBI. The RBI Tandem Accelerator facility is actively involved in educational activities. In partnership with the UoZ, students in physics use the accelerator facility to perform seminars, BSc, MSc and PhD theses. With the upgraded nuclear research end station, possibilities for the expanded educational programmes are opened. Recently University of Zagreb and RBI started joint post-graduate studies in Nuclear Physics. The RBI Tandem Accelerator facility has been used for practical demonstrations and experiments for students. Additional potential users of the facility in educational and applicative activities are other universities with Physics Departments from Croatia (Split and Rijeka), as well as the universities from the WBC region.
Increased opportunities for popularization of science: The RBI Tandem Accelerator facility is open for general public on regular RBI Open Days and for visits of students and pupils. According to our experience modern experimental facilities are very attractive to general public and attract positive interest of general public for research and development activities in general.
The very fact that our four research groups are partners in the FP7 project and our increased communication have very positive influence on strengthening of the collaboration between partner institutions. In the recent period two new proposals for experiments at international experimental facility were approved in which researchers from all partnering institutions involved in the CLUNA project are participating with work power and equipment. Another proposal is submitted to GANIL two weeks ago for expert committee evaluation. Further research projects with participation of all CLUNA partners are planned for the near future, some of them also at the upgraded RBI experimental facility.
Dissemination
Main dissemination activities were grouped within WP7. Objectives of this WP were:
(i) to realize dissemination of knowledge and project results to international nuclear physics community and general public; and
(ii) to present to general public methodology, goals and results of research in nuclear physics, particularly positive influence of this research on today's life of people.
The design and development of web site on activities of the CLUNA project, including some general content on the nuclear reaction and structure studies, was performed during the first project year, and the web site was launched in February 2009, with continuous updating. During the second project year the project web site was enlarged to include pages in Croatian language, written by RBI/UoZ staff with general content on nuclear physics and related research presented on level understandable to high school students, with aim to popularize nuclear physics and science in general.
Exploitation of results
Implementation of WP2 resulted with the availability of helium beams for future research. In addition, expertise has been acquired for the production of new ion beams of 9Be, 10,11B, 13C and 18O at the RBI Tandem accelerator facility. These ion beams are not available only for nuclear physics experiments, but also for interdisciplinary research and services.
In short, the exploitable knowledge of the CLUNA project can be summarized as follows:
1) exploitable knowledge on production of new ion beams can be used in accelerator running services with aim on applications of low energy accelerators. It is know-how available from 2010 owned by RBI,
2) expertise in use of silicon strip detectors can be used in interdisciplinary research and analytical services for material analysis and development of advanced materials. It is know-how available from 2011 owned by RBI,
3) expertise in data acquisition systems can be used in interdisciplinary research and analytical services for running complex experimental instrumentation. It is know-how available from 2010 owned by RBI,
4) exploitable knowledge on measurements with unstable beams including specificities of experimental setup and data analysis will be used in nuclear physics research for general advancement of knowledge in nuclear physics, but also can be used in interdisciplinary research for highy specialized analytical services (for example deposition of long-lived radio-isotope in materials, biological or medical samples etc.). It is know-how available from 2011 owned by RBI,
5) expertise in use of neutron detectors can be used in interdisciplinary research and analytical services for material analysis, development of advanced materials and homeland security (neutron detection from radioactive materials). It is know-how available from 2011 owned by RBI.
In addition, project CLUNA exploitable foreground is commissioned research instrumentation:
1) upgraded experimental end station for nuclear physics research can be used not only for basic research in nuclear physics, but also for interdisciplinary research (astrophysics, materials characterization). Fully upgraded is from 2010,
2) detection system for charged particles can be used for nuclear physics research and interdisciplinary research at RBI, INFN-LNS and other European accelerator facilities from 2010. It is owned by RBI,
3) neutron detection system also can be used for nuclear physics research and interdisciplinary research and applications (material analysis, detection of radioactive materials in homeland security) at RBI, INFN-LNS and other European accelerator facilities from 2010. It is owned by RBI.
Project website: http://zef.irb.hr/cluna
Mailing lists:
all staff: cluna-team@lnr.irb.hr
management staff: cluna-admin@lnr.irb.hr
Coordinator:
Neven Soic
Division of Experimental Physics, Ruder Boskovic Institute
Bijenicka 54, HR-10 000 Zagreb, Croatia
Phone: +38-514-561026, Email: soic@lnr.irb.hr
Project Manager
Stjepko Fazinic
Division of Experimental Physics, Ruder Boskovic Institute
Bijenicka 54, HR-10 000 Zagreb, Croatia
Phone: +38-514-571254
Email: stjepko.fazinic@irb.hr
Representative of INFN-LNS and member of Project Management Board
Pierpaolo Figuera
INFN Laboratori Nazionali del Sud
via S. Sofia 62, I-95123 Catania, Italy
Tel. +39-095-542297
Email: figuera@lns.infn.it
Representative of University of Birmingham and member of Project Management Board
Martin Freer
School of Physics and Astronomy, University of Birmingham
Edgbaston, Birmingham, B15 2TT, UK
Tel. +44-121-4143384
Email: mf@np.ph.bham.ac.uk
Representative of University of Zagreb and member of Project Management Board
Matko Milin
Department of Physics, Faculty of Science, University of Zagreb
Bijenicka c. 32, HR-10 000 Zagreb, Croatia
Tel. +38-514-605545
Email: matkom@phy.hr
Experimental nuclear physics is one of the top research activities at the Ruder Boskovic Institute (RBI), the largest Croatian research center in science and applications. The RBI nuclear physics group has strong link with the research group at the University of Zagreb (UoZ). RBI scientists perform experiments at the RBI Tandem accelerator facility and at the top EU experimental facilities in collaboration with the prominent EU research groups in the field, including partners from the Laboratori Nazionali del Sud INFN (INFN-LNS), Catania, Italy and the Nuclear Physics Group from the University of Birmingham (UoB), UK. With CLUNA we strengthened scientific relationships, the exchange of know-how and sharing of experience between RBI, UoZ, INFN-LNS and UoB partners in the research field of our common interest, focusing on the studies of nuclear molecules and other areas at the forefront of research for new phenomena in nuclear physics.
This was achieved by:
(i) reinforcement of RBI experimental capabilities through the upgrade of the local experimental facility,
(ii) exchange of personnel between partner institutions, hiring and training of young staff at accelerator facilities,
(iii) organization of workshops and short term training events, dissemination of project results to specialists and general public.
In particular, the existing nuclear physics experimental end station, including detector system, at RBI Tandem Van de Graaff accelerator was upgraded. New low-noise high-power electricity system and gas target system for use of the helium and hydrogen gas were designed and built. The upgraded silicon detector array for detection of charged particles was accompanied with the detection system for neutrons. Both detection systems were coupled together in the data acquisition system to enable simultaneous detection of neutron and charged particles. Data acquisition system was completed and commissioned. Procedures for production of new ion beams for nuclear physics experiments, including 3He, 4He, 9Be, 10,11B, and 18O, have been adopted and as a result those beams are now routinely available. Water and gas isotopically enriched in 18O required for production of the 18O beam, 4He and 3He gas for production of related isotopic ion beams were purchased to sustain future production of related ion beams. Upgraded research infrastructure for low energy measurements at RBI and complementary facility at LNS for intermediate energy measurements through this partnership contribute to the increase of research opportunities for even broader European experimental nuclear physics community.
Three outstanding graduated students were employed, now all being supported as PhD students by local funds. Extensive visits of junior and senior staff between the partners were organized to exchange know-how and to share experience. Workshop on "Inverse kinematics measurement technique for gas targets" was held in April 2010 at INFN-LNS. Two planned RBI workshops, on elastic and inelastic scattering as a toll in spectroscopic studies, and on nuclear molecules, were merged into one longer workshop, held in April 2011. Practical training at the SPIRAL facility of the GANIL laboratory was held in autumn 2010. This event provided excellent opportunity for the RBI/UoZ researchers to work in international environment at top class international laboratory, enlarging their research experience. The new RBI detection system functioned well in complex experimental conditions applied in these trainings.
Project Context and Objectives:
The overall objective or goal of CLUNA project is to strengthen relationships, to exchange the knowhow and to share experience between Ru?er Bokovi? Institute (RBI), Laboratori Nazionali del Sud INFN (INFN-LNS), School of Physics and Astronomy, University of Birmingham (UoB) and Faculty of Science, University of Zagreb (UoZ) in the research of common interest. The focus is on studies of nuclear molecules and other related topics at the research forefront for new phenomena in nuclear physics.
The project particularly aims to boost scientific and technological research potential of the RBI experimental facility for common RBI-LNS-UoB-UoZ studies with low energy ion beams. This includes an upgrade and renewal of the existing nuclear physics experimental end station at RBI Tandem Van de Graaff accelerator to improve its capabilities for collaborative research in low energy nuclear physics. Important activities in realization of the objectives are the exchange of personnel between partner institutions, hiring and training of young staff at accelerator facilities and organization of workshops and short term training events.
In particular, specific objectives of CLUNA are:
(1) To upgrade the existing nuclear physics experimental end station, including detector system, at the RBI Tandem Van de Graaff accelerator and production of new beams at the accelerator facility.
This includes:
(i) Removal of the existing scattering chamber to the position more appropriate for new proposed experimental activities (including modeling of the ion beam optics, changes on the beam line, new collimating system, changes on vacuum system), and building of new vibration-free chamber stand.
(ii) Upgrade of the chamber in order to allow experiments with gas target for inverse kinematics measurements (including development and assembly of new flanges, new valves for pumping and venting operations, control of the gas flow, development and assembly of entrance window). Development of the helium gas target as well as production of new beams at the facility would enable measurements of resonant (in)elastic scattering in the inverse kinematics, a powerful method already applied worldwide and at the INFN-LNS facility. Collaboration with the INFN-LNS and UoB groups is essential, since they have large experimental experience in the field.
(iii) Renewal of the noise-free high power electricity system with proper grounding at the experimental end station, which will allow use of the recently acquired detector and electronics setup (with much larger number of detectors and electronic units than in the former setup) required for new experimental activities.
(iv) Acquisition, assembly and commissioning of several fast neutron detectors and associated electronics, including building of detector mounts, and coupling of the neutron detectors to the existing detection system for charged reaction products. This new detector system, via detection of neutrons from nuclear reactions, will make possible new research activities for institutions involved in the proposal and will significantly increase research capabilities of the RBI facility, which are presently limited to the detection of charged reaction products. It also includes development of adequate fast neutron shielding for neutron detectors and chamber's Faraday cup.
(v) Upgrade of the existing detection system for charged reaction products with new large area thin (20 - 35 ?m) silicon detectors for detector telescopes (particle identification) and acquisition of adequate preamplifiers for these detectors. This upgrade will extend detectable energy range of charged reaction products. Upgraded detection system including neutron detectors will be compact and transportable for measurements at different experimental sites including INFN-LNS.
(vi) Continuous and increased usage of 3He and 4He beams, and production of new beam species of interest in nuclear cluster studies: 9Be, 10,11B and 18O. In addition to standard heavy ion beams from the EN Tandem accelerator, the 3He and 4He beams have been used in Zagreb since the commissioning of ion source for helium negative ions in 2004. Nevertheless, several improvements and upgrades of the experimental end station for nuclear reaction studies are needed to further explore usability of these beams.
(vii) Reinforcement of the RBI group human potential by hiring new young researcher(s) who will be involved in the upgrade and later use of experimental end station. Young researcher(s) will acquire knowledge and experience from senior researchers of all four partner institutions and will be involved in all activities of the RBI group. Strengthening of RBI group with young researcher(s) will allow more frequent and efficient use of the upgraded experimental end station. Hired young researcher(s) will start postgraduate studies during the first year of employment. Usual Croatian practice for hiring of young researchers imply that research group finds graduated student first and then apply for his/her position. It usually takes a year or even longer to employ new PhD student. Through this project we would require funds for covering young researcher expenses for period before official employment at RBI by Croatian Ministry of Science, Education and Sport (MSES). Once employed by MSES, young researcher will continue his/her employment at RBI until he/she obtains PhD degree, and possibly later as a research associate.
(2) To strengthen the collaboration between RBI, UoZ, INFN-LNS and UoB through the exchange of knowledge and experience relevant to the field, leading to future common experiments and knowledge transfer at international level
This includes:
(i) Exchange of knowledge and experience in the field of "Data acquisition and front end electronics" between the UoB and RBI/UoZ staff, including training of young researcher(s) from RBI at UoB. Staff at UoB has valuable experience with electronics and data acquisition for nuclear reaction measurements, which is very important in upgrading of the RBI experimental capabilities.
(ii) Exchange of knowledge and experience in the field of "Inverse kinematics measurement techniques" between the INFN-LNS, UoB, UoZ and RBI research personnel, including knowledge transfer from the INFNLNS to RBI on production and maintaining of gas targets, and training of young researcher(s) from RBI at INFN-LNS experimental site.
(iii) Exchange of knowledge and experience in the field of "Experimental techniques employed in cluster studies" between RBI, UoB, UoZ and INFN-LNS through specialized workshops and training events at RBI facility.
(iv) Short term specialized training of RBI researchers at one of the European top research laboratories for knowledge sharing in experimental techniques for nuclear structure studies and work of the RBI staff in an international environment with researchers from partner institutions.
(3) Dissemination of knowledge and project results
This includes:
(i) Participation of the RBI research staff at international conferences on nuclear structure and reactions. RBI researchers will present there their new results obtained in collaborative work with partners from INFN-LNS and UoB.
(ii) Some of our collaborators from other European institutions (Laboratori Nazionale di Legnaro Italy, University of Surrey UK, University of Caen France etc.) have also shown interest for experiments at RBI facility. Presentation of upgraded RBI facility and its capabilities for new experimental activities to broader European nuclear physics community through personal contacts would lead to new collaborative experiments at RBI, increasing the number of international users of the facility and will increase RBI international reputation.
(iii) RBI staff will work on popularization of science in general and specifically nuclear physics through presentations of upgraded nuclear physics end station to general public during the RBI "Open Days" and lectures for general public, organization of seminars on nuclear physics at RBI. For educational purposes, the facility will be used in the nuclear physics undergraduate and graduate courses as well as for the experimental part of the BSc, MSc and PhD thesis. Staff of other partner institutions will work accordingly at their local environment.
(iv) upgraded and renewed experimental end station at RBI will be presented at a new web site, as well as all other activities of RBI group and RBI-UoZ-LNS-UoB collaboration.
INFN-LNS is one of the two accelerator laboratories for nuclear structure and reactions research in the Italian national network for Nuclear Physics research (INFN) and is one of the top Italian institutions for nuclear physics research.
Nuclear Physics Group from the University of Birmingham is one of the most active UK research groups in nuclear physics with high scientific impact.
Researchers from INFN-LNS and RBI have been working in strong collaboration for 30 years and performed many experiments at INFN-LNS, other EU experimental facilities and several experiments at the RBI accelerator facility. Collaboration between RBI and Birmingham group started in 2000 and resulted so far with more than 30 experiments at international facilities. Through this project we will strengthen partnership between these four institutions for benefits of all partners: RBI will improve its research capabilities in nuclear physics and will serve as a competitive research centre for low energy nuclear reaction studies at European level, INFN-LNS will increase number of users of its intermediate energy facilities and will increase its value as the research centre at European level, UoB will have two new sites for complementary types of nuclear reactions measurements and UoZ will have upgraded local facility for research and educational activities. Moreover, tighter partnership of these four already successful groups will form highly competitive collaboration at the international level which will propose and perform future experiments at INFN-LNS, RBI and other European accelerator facilities.
By reinforcing the existing research potential of the RBI nuclear physics end station through this project, the facility will be able to continue and extend its traditional light nuclei collisions studies and will provide services to the collaborators in a more efficient way. The realization of proposed project will also open the possibilities to offer new research activities to the WBC region and to the broader European nuclear physics community, as well as to strengthen RBI presence at the European Research Area in this specific research field.
Specific project objectives are accomplished through work packages. The first work package (WP1) groups together all project management activities, and the last one (WP7) deals with the project dissemination activities. WP2 to WP6 are technical work packages, i.e. they group together activities leading to implementation of the scientific and technical objectives.
- Work package 1 (WP1): Project Management
- Work package 2 (WP2): Improvements of experimental capabilities for nuclear structure research at RBI
- Work package 3 (WP3): Young researcher employment and education
- Work package 4 (WP4): Data acquisition system and front-end electronics
- Work package 5 (WP5): Measurement techniques for inverse kinematics reactions
- Work package 6 (WP6): Experimental techniques in nuclear cluster studies
- Work package 7 (WP7): Public awareness and dissemination of project results
Project Results:
Main S&T project results/foreground are presented for each technical work package (WP2 to WP6).
Work package 2 (WP2): Improvements of experimental capabilities for nuclear structure research at RBI
The objectives of WP2 are:
(i) to upgrade and renew the existing nuclear physics experimental end station at the RBI Tandem accelerator for nuclear physics measurements in order to increase its experimental capabilities;
(ii) to increase the performance of existing detection system at the RBI nuclear measurement end station in order to increase its usability for nuclear structure and reaction studies; and
(iii) to assure long term delivery of 3He and 4He beams and to make available new ion beams at the Tandem facility.
The old experimental end station had limited capabilities for nuclear structure and reactions studies, but was already in use for some simpler collaborative research activities, primarily in collaboration with the INFN-LNS research group. Part of work on its upgrade, including acquisition of new detector system for charged particle detection, started several years before the CLUNA beginning. Yearly available local funding was very limited, but during the years large part of required equipment was collected. The CLUNA funds were used to finalize and commission the experimental setup.
New low-noise high-power electricity system
New low-noise high-power electricity system was designed and built at the new chamber position. The experimental end station requires electricity for normal operation: vacuum elements like mechanical and turbo-molecular pumps or mechanical elements of the scattering chamber like lid opener use electricity. Additionally, all kind of detectors, including different types of silicon detectors for charged particles, and all electronic units for signal processing from detectors, require electricity (as example for bias voltage) for their operation. Particular care should be paid to electricity source for detectors and associated electronics, because electric signals from the detectors are very small (in the milivolt range) and could be disturbed by electronic noise from various sources. To reduce a noise and increase performance of the detectors and associated electronics chain (preamplifier, spectroscopic and timing amplifiers, logic units, analog-to-digital converter), their electricity source has to be well isolated from all other power systems and properly grounded. Initial power system used at the experimental end station was not properly separated from the rest of the building electricity system and its power was enough only for up to ten electronics chains. This is adequate for the old small silicon detector system used at the experimental end station before, but is not enough powerful for the new silicon detector array composed of large number of silicon strip detectors. For this reason, a new low-noise high-power electricity system was designed and built at the experimental end station. In the first year of the CLUNA project experimental end station was moved to the new, more appropriate position for the new experimental activities. So, the work on the new power system was performed during this movement of the end station. Actually, the work on this task started before the start of the CLUNA project due to its importance for our experimental program. Significant part of the equipment for this task (15 kW transformer, cables, small electrical equipment and materials) was acquired before the CLUNA start and these costs were covered by our national grant. The most of the work was performed in the first months of the CLUNA project and the work costs of the RBI employees were covered by the CLUNA project funds. The new system has enough power (15kW) for use of detector system with 250 signals and associated 250 electronic chains. Its noise level is reduced to the lowest possible. The setup was tested twice using our new detection system, and the system is now in full operation.
Gas target system at the experimental end station
Initially, the RBI experimental end station was suitable for experiments with thin foils as target only. Introduction of the gas target measurements, particularly suitable for low energy beams provided by the RBI Tandem Van de Graaff accelerator, presents a large increase of experimental capabilities of the facility and opens the new research topics on nuclear structure and nuclear astrophysics research at RBI. Of particular interest are hydrogen (proton and deuteron) and helium targets. Main experimental technique with gas targets is resonant scattering in inverse kinematics regime, when heavy beam particle is scattered off the light target particle detected in the measurement.
Originally, in the project proposal only helium gas target was considered. The work on the design, purchase of required hardware, and on building of the gas target system was finalized during the first year of the project. New valve was mounted on the scattering chamber for gas inflow. The scattering chamber was isolated from the vacuum in the beam lines with entrance window which was designed, manufactured and tested. Various designs of the window, the range of the window size and thickness as well as various materials for the window were tested before the final setup was accepted and commissioned. For low intensity ion beam measurements Mylar window is behaving well and it is preferred material due to very low cost. However, measurements with high intensity ion beam require much stronger, but also very expensive, HAVAR window. Introduction of the entrance window required replacement of the existing collimator system with the new one. Beam optics for the new collimator was calculated, and collimator was designed and manufactured.
During the work on this task, the RBI group developed new research program on nuclear astrophysics and started new research project managed by European Science Foundation under the EuroGENESIS program (part of the Eurocores program) funded by Croatian National Foundation for Science and High Education (Nacionalna Zaklada za znanost i visoko obrazovanje - NZZ). It came out that for nuclear astrophysics studies hydrogen gas target would be highly desirable. Also for nuclear structure studies, our main research topic, hydrogen gas target (in the first instance deuterium gas) would be very useful. The essential difference between helium and hydrogen target is that hydrogen is flammable, which requires additional security measures in handling gas. We found out that simple changes on the gas target system and small additional investment could enable the use of hydrogen gas in the target system. We therefore redesigned the gas target system. New pumping system for gas outflow was purchased and installed. All required work was performed by the end of July 2009, with a small delay compared to the original planning.
Silicon detector array
Essential step in increasing research capabilities and capacities of the RBI facility in nuclear structure and reaction studies was completion and commissioning of the detection system for charged particles. Core of the detector system was acquired before the start of the CLUNA project: five large area thick (500 µm) position sensitive strip detectors and four large area thin (50 µm) quadrant detectors, as well as preamplifiers, amplifiers, analog-to-digital converters (ADC) and most of other electronics for 160 signal channels.
Neutron detector array
For further enlargement of the RBI experimental facility capabilities and capacities for low energy nuclear physics research, commissioned large silicon detector array for detection of charged particles was accompanied with new detection system for neutrons. Neutrons, neutral particles building atomic nucleus, are reaction products in many processes important in nuclear physics and nuclear astrophysics. Availability of the neutron detection system makes possible a new sort of experiments designed to study these processes at the RBI accelerator facility and other facilities in Europe at which we regularly perform experiments.
Works on tasks related to neutron detector array were delayed regarding to original work plan due to delay on commissioning of the silicon detector array and the data acquisition system. The reason for this delay was the above mentioned hardware failure at the RBI Tandem Van de Graaf accelerator facility, which put our experimental end station out of use for six months. Work on acquisition of the neutron detectors started in the second half of 2009. Detailed study on available neutron detectors on the market was performed. Extensive discussions within the project partners and our collaborators from other institutions with experience on neutron detection (we appreciate great contribution from our collaborators from the GANIL and LPC Caen France) was taken for decision on the detection system properties most suitable for our research activities.
Work performed on DAQ setting and achieved results
Very important step in increasing research capabilities and capacities of the RBI facility for nuclear structure and reaction studies was completion and commissioning of the detection system for measurements of nuclear reaction products. In the measurements, analog electric signals from various detectors produced by detected reaction products are processed in electronics. The electronics role is double-fold:
1) to produce amplified and reshaped useful electric signals,
2) to produce logic signals related to detected particles which are required for selection of interesting events from background and other non-relevant events.
These logic signals are processed in various logic electronic units resulting in trigger signal which signalize detection of physically relevant events. Such selection mechanism has to be fast and efficient due to high counting rate of the detection system required to collect significant statistics of interesting events. Obviously, trigger cannot (or can in only very limited number of cases) provide clear online separation of all physically interesting events from background and non-relevant physics, so its main role is to significantly reduce all background/unwanted processes and enable further processing of reduced volume of data. Such accepted signals are then converted to digital values in Analog-to-Digital Converters (ADC) activated by trigger signal. These data are recorded on event by event basis for later offline analysis and extraction of results.
Part of electronics system performing reduction of events, conversion of data to digital form and recording of data is called Data Acquisition system (DAQ). As was the case with other parts of the detection system for measurements of nuclear reactions, core of the DAQ was acquired before start of the CLUNA project: many logic electronics units, VME crate, 6 analog-to-digital converter (ADC) units with 32 channels each, VME processor and ADC control unit. This core makes possible building of the DAQ for processing of 192 signals from the detectors using DAQ software MIDAS (http://npg.dl.ac.uk/MIDAS/) developed at the Daresbury Laboratory in UK.
One of the CLUNA project goals was finalizing and commissioning of the DAQ. The MIDAS software communicates with the VME processor, uploads the operating system into the VME processor, enables settings of the various units in the DAQ and receives and records data from the DAQ to the computer hard disc. Software was originally written for Sun operating system Solaris running on the Sun computers built on SPARC architecture. It was recently modified to work on Solaris operating system on computers with Intel and AMD architecture. There are also versions of MIDAS for other operating systems, like Linux and Microsoft Windows, but the most reliable and highest performance version is still built for Solaris operating system. The University of Birmingham group members have vast experience in running older versions of MIDAS on Solaris SPARC computers connected to VME DAQ systems and their experience and knowledge have been of the prime importance for setting up the DAQ system at RBI. Their support was realized through work package 4.
It was decided to build DAQ on Solaris operating system due to its favourable performance and experience of the Birmingham group. Detailed study of the available hardware options and requirements on computer set by our detection system showed that the best value for money provide Sun server computers built on AMD architecture. The server Sun Fire X4100 M2, computer in the middle class of Sun servers on the market in Croatia, running on the latest version of Solaris operating system, was purchased using national funding. Solaris was reconfigured for the use as DAQ server and the latest version of the MIDAS software for INTEL/AMD architecture was installed and configured.
The final and full test of complete detection system, including silicon detector array, electronics and DAQ, was performed during the workshop held at INFN-LNS Catania in April 2010. Test was done using large detector array with six detector telescopes giving 288 detector signals into the electronics and the DAQ system. The research equipment of our partners from INFN-LNS and University of Birmingham was used together with our equipment. Beam from the Tandem accelerator of the INFN-LNS was used in the test. In this test very complex experimental setup and conditions were applied. The all the components of the detection system were running smoothly, providing final evidence for successful commission of the detection system.
Production of ion beams
Work on production of new ion beams at the RBI Tandem accelerator started according to the plan. The production procedure for the 18O beam was developed during the first project year. Commissioning of the first 18O ion beam was successfully performed in April 2009 and it is now available for regular use. We purchased more material (water and gas) isotopically enriched in 18O required for production of the 18O beam for future research at the RBI accelerator facility.
In order to maintain possibilities for delivery of these ion beams for future research at the RBI accelerator facility, the necessary material was purchased. This includes water and gas isotopically enriched in 18O required for production of the 18O beam, 4He and 3He gas for production of related isotopic ion beams.
The production of the 14C beam has been postponed for future. The reason for this decision is related to the possible future use of the EN Tandem Accelerator as Accelerator Mass Spectrometer (AMS). This is currently the most sensitive method for radiocarbon dating and there is at the moment an interest at the RBI to introduce this technique at the EN Tandem Accelerator. Since radiocarbon dating is based on the use of 14C ion beams, its parallel use for nuclear physics experiments could result with unreliable radiocarbon dating measurements.
To summarize, all the tasks associated with WP2 were successfully completed. As a result, the experimental end station is fully upgraded according to the project description of work, with some additional improvements which required small additional investment. Upgrade and renewal of the existing nuclear physics experimental end station increased its experimental capabilities. The RBI detection system is enlarged with the large silicon detector array for charged particles detection, neutron detector array, associate front-end electronics and data acquisition system. The system is fully operable and in usage for nuclear structure and reaction studies as well as for research in nuclear astrophysics. Availability of helium beams for future research have been secured and new ion beams of 9Be, 10,11B, 13C and 18O are available for experiments at the RBI Tandem accelerator facility.
Total cost of this work package was 196560 ?, 25% more than originally planned.
Work package 3 (WP3): Young researcher employment and education
The objective of WP3 was to strengthen the RBI group human potential for project activities and research. This objective was realized through employment of young researchers and their education for work on CLUNA project and on nuclear physics research.
Activities started in May 2008. The standard procedure for employment of research PhD student at the RBI was followed. Public call for open position was published in the Official Gazzette of the Republic of Croatia "Narodne novine" (see http://www.nn.hr/sluzbenilist/ oglasni/index.asp online) no. 71, daily newspapers "Vjesnik" (see http://www.vjesnik.hr online) on June 20th 2008 and on the RBI official web page (see http://www.irb.hr online). Requirements for the position were: BSc degree in physics, preference for experimental work in nuclear physics, final average mark at graduated studies greater than 4.0 (out of maximal grade of 5.0) candidate should be fluent in English and have affinity for team work in international environment. Duties of the new employee included engagement in all activities of the CLUNA project, particularly in work on renewal and update of the experimental end station at the RBI accelerator facility and associated detector setup, including acquiring of knowledge and experience required for experimental research work in nuclear physics.
We followed the idea to enroll young researcher in postgraduate studies in nuclear physics during the first year of employment. In addition, in order to sustain employment for a period after CLUNA, in parallel with the employment, a PhD student position at RBI would be asked for young researcher from Croatian Ministry of Science, Education and Sport (MSES). In case of MSES approval before the end of the project, another young researcher would be employed, with parallel support request from MSES. Strengthening of RBI group with young researcher would allow more frequent and efficient use of the upgraded experimental end station.
At the beginning of the project implementation we found two outstanding graduated students for this position. On 1st July 2008 Ms. Iva Bo?i?evi? was employed. She graduated physics at University of Zagreb in spring 2008. She was employed on CLUNA project until 31st December 2008. From1st of January 2009 funding for her position was secured by MSES in the LIBI research group at the RBI accelerator facilities, also involved in the CLUNA project.
Therefore, another graduated student, Mr. Lovro Propolec, was employed on 2nd February 2009. In early 2010, coordinator of the CLUNA project re-applied to MSES for PhD student position for Lovro (the first application in 2009 was not approved due to very limited number of positions). Application was approved in late 2010 and Lovro has been employed by MSES on six years PhD student contract, starting from the December 9th 2010.
Lovro significantly contributed to the work on all the tasks of the experimental end station upgrade, work on setting up the data acquisition system and testing of acquired silicon detectors and associated electronics. He was educated and trained by senior RBI and UoZ researchers involved in the CLUNA project on experimental techniques and methods in nuclear structure research, settings and use of silicon detectors and electronics and data analysis. INFN-LNS and UoB researchers transferred their knowledge and experience to him during visits at RBI, during Lovro visits to INFN-LNS and UoB, and on CLUNA workshops and practical training event.
Lovro attended international conference "Nuclear Structure and Dynamics 09" (conference web page is http://www.phy.hr/~dubrovnik09/ online) which CLUNA researchers from RBI/UoZ coorganized (Matko Milin from UoZ was Scientific Secretary, Suzana Szilner from RBI was cochair, Neven Soi? of RBI was member of Local Organizing Committee) in Dubrovnik on May 3rd to 9th 2009. Conference was attended by large number of world class researchers who gave presentations of their contemplate research results. This was excellent opportunity for young researcher to learn about state-of-the-art research in nuclear physics from world experts.
Lovro also attended summer school on nuclear physics by European Summer University "The secrets of the atomic nucleus" in Strasbourg France from June 28th to July 4th 2009 (the school web page is http://esc.u-strasbg.fr/2009/). Summer school was organized with 12 lectures given by world experts in the field, 2 round tables and 3 practical student workshops. Lovro attended practical training on detection of neutrons which was particularly useful in setting up neutron detector array at RBI (WP2).
He attended short training on beam and target production at INFN-LNS accelerator facility (March 15 - 18, 2009), practical training on the use and setting up of the silicon detector array and all associate electronics from preamplifiers to DAQ (April 7th - 12th), and another training on calibration of position sensitive silicon strip detectors and analysis of data collected with such detectors (April 24th - May 2nd). He also attended the workshop held at INFN-LNS from April 13 - 23 2010. More details about the workshop are given in section on WP5. The short practical trainings with equipment were particularly useful for Lovro to increase his level of knowledge and experience and enable higher level of knowledge transfer at the INFN-LNS workshop.
Total cost of WP3 in the project was 58306 ?, 16% more than planned.
Work package 4 (WP4): Data acquisition system and front-end electronics
The objectives of WP4 are:
(i) to strengthen the collaboration between UoB and RBI/UoZ research groups;
(ii) to exchange knowledge and experience on data acquisition and electronics for nuclear reaction measurements between UoB, RBI and UoZ researchers; and
(iii) to help realization of WP2 and WP3. In particular, for WP2 objectives, support is needed in assembly, testing and commissioning of VME data acquisition system and in coupling of the existing detection system for charged nuclear reaction products with a new one for the fast neutron detection and for WP3 is related to education of young researchers.
All WP4 objectives were achieved. Collaboration between UoB and Zagreb group has been enhanced. RBI research staff acquired knowledge and experience required for setup of electronics and DAQ system. Coupling of neutron detector array and silicon detector array into common DAQ setup was successfully realized. It came out that for full realization of the project objectives we needed less exchange visits than planned, because RBI and UoB researchers met regularly for experiments and these occasions were used also for CLUNA activities. For this reason, realized staff efforts and accordingly expenses, were smaller than expected.
Total cost of WP4 during the project was 6711.25 ?, some 30% of the planned funding.
Work package 5 (WP5): Measurement techniques for inverse kinematics reactions
Objectives of WP5 are:
(i) to strengthen the collaboration between INFN-LNS and RBI/UoZ research groups;
(ii) to exchange knowledge and experience on measurement techniques for inverse kinematics reactions using gas target, and on design and assembly of gas targets between research staff from INFN-LNS and RBI/UoZ; and
(iii) to help realization of WP2 and WP3 (education of young researcher).
All WP5 objectives were accomplished. Collaboration between research groups from all the four partner institution is strengthened compared to the situation before the CLUNA project. RBI researchers gained new knowledge and experience. New knowledge and skills were successfully used in realization of WP2 and WP3 tasks.
During the first project year the INFN-LNS staff spent 2.5 person-months, while RBI staff spent 3.5 person-months on the activities of this WP. Costs of this WP in the first year were 7699.57 ?.
In total, during the second project year RBI staff visited INFN-LNS for 79 person-days which include participation of five researchers at the workshop, training of young researcher and visits for knowledge and experience exchange of senior researchers. INFN-LNS staff efforts for this work package in total were 5.5 person-months. UoB staff efforts for WP5 were 0.6 person-month. UoZ staff efforts were 0.5 person-month. Costs of the WP5 were: 12149.07 ? for RBI (includes all travelling expenses to Catania and transport of the equipment for the workshop from Zagreb to Catania and back), 7668 ? for INFN-LNS, 1653.16 ? for UoZ and 1927.27 for UoB.
During the third project year, staff efforts of RBI were 0.75 p-m, INFN-LNS 0.75 p-m and UoZ 0.3 p-m. Costs of the WP5 were 2407 for INFN-LNS and 1199 for UoZ.
Total cost of this WP during the project was 34703 , 17% less than originally planned.
Work package 6 (WP6): Experimental techniques in nuclear cluster studies
The objectives of this WP are:
(i) to strengthen the collaboration between RBI/UoZ, INFN-LNS and UoB;
(ii) to exchange knowledge and experience on experimental techniques for nuclear structure studies between all partner institutions; and
(iii) to help in realization of WP2, WP3, WP4, WP5 and WP7.
Workshop at the RBI
Two workshops were planned at the RBI accelerator facility under WP6, the first one with the topic on elastic and inelastic scattering as a tool in spectroscopic studies, and the second one on nuclear molecules. The first workshop, on the use of scattering measurements for spectroscopic studies of nuclei, was planned to have strong practical component with extensive training of the Ruder Boskovic Institute and University of Zagreb staff at the RBI accelerator facility. It was planned that experienced staff of University of Birmingham and Laboratori Nazionali del Sud transfer their practical knowledge on the use of experimental equipment for measurements of scattering processes with light nuclei to RBI and UoZ researchers. It was planned to concentrate the second workshop, on exotic structure in light nuclei similar to atomic molecules, to analysis techniques of the experimental data resulting with information on nuclei structure and experimental evidence for nuclear molecules in light nuclei. These two workshops were complementary dealing with clustering phenomena in nuclear physics, scientific topic behind the CLUNA project. The Project Management Board proposed and the Project Officer approved to merge these two workshops in one, covering the planned topics of both workshops, including additionally interrelation between experimental technique (measurement of scattering processes, topic of the first workshop) and structural phenomena in nuclei (nuclear molecules, the topic of the second workshop). In this way one combined workshop provided additional added value to the project. Merging of the two workshops gave a chance to attendances to work on both subjects at the same time and easier follow a path from experimental work on measurements, which provide required data, to data analysis and interpretation of experimental results, which finally results with the new scientific information. Initially, the first workshop, one with the practical training requiring ion beams in the RBI experimental chamber, was planned to be performed during the 2nd project year, but due to the vacuum pump failure and six months (Sep 2009 - Mar 2010) unavailability of the beam, we were not able to realize it at that time. This workshop was rescheduled to Sep 2010. In summer 2010 GANIL management informed us that the two experiments in which were involved researchers from the CLUNA project, as well as our CLUNA practical training event (part of WP6) were scheduled for the period from middle September until the beginning of November the same year. For this reason the workshop at Zagreb was postponed to December 2010. Unfortunately, another hardware failure at the RBI Tandem accelerator facility, malfunction of power supply of the switching magnet (one which delivers ion beams to the experimental end lines), hampered realization of the workshop. Power supply of the switching magnet was repaired in January 2011 and the Tandem accelerator facility was back to normal operation by the end of January 2011. Due to the quite short time left until the end of the CLUNA project, merging two workshops in one sounded as good option. Merging has also saved time and funds required for the full realization of the project.
This workshop was organized in the same way as the one at INFN-LNS. It was mainly dedicated, especially the first half of the workshop, to practical work with the research instrumentation, including intensive training on equipment usage in the measurements of the scattering processes. For this training, some research equipment from Birmingham and Catania was required to complete experimental setup based on the RBI equipment. Data acquired from the scattering measurements provide important results on spectroscopy of nuclei which obey the laws of quantum physics: characteristics of the nucleus excited states. Full characterization of the excited states makes possible understanding of structure of the studied nucleus. The second part of the workshop was dedicated mainly to offline analysis of the experimental data, interpretation of the results on nuclear spectroscopy and extraction of the results on nuclear structure from the knowledge of nuclear spectroscopy. Techniques and methods of the analysis were demonstrated on the experimental data collected during the workshop. Experienced researchers from UoB and INFN-LNS, having complementary expertise on various steps in this complex process of acquiring new results on nuclear cluster structure and nuclear molecules, were giving lectures and leading training sessions with the help of senior Croatian scientist with adequate expertise for the considered topic.
This workshop was successfully realized. All RBI equipment was tested in experimental conditions different than the ones in the previous workshop at INFN-LNS and worked well in joint complex experimental setup with INFN-LNS and UoB equipment. RBI researchers, particularly PhD students, collected new knowledge and experience on setting up and running complex measurements, running measurements for spectroscopic studies and the data analysis which results in the new knowledge on nuclear structure.
Practical training at GANIL
The next large event planned in the CLUNA project was practical training of the RBI/UoZ researchers at the radioactive ion beam facility SPIRAL located at GANIL laboratory in Caen, France (see http://www.ganilspiral2.eu/ online). This facility is currently unique facility in the world considering wide spectrum of reaccelerated unstable ion beams of light nuclei and the beams intensity, purity and focusing properties. This event provided excellent opportunity for the RBI/UoZ researchers to work in international environment at the top class international laboratory, significantly enlarging their research experience.
Experimental work with unstable ion beams is largely complementary to the work with stable ion beams due to very different constraints on experimental techniques and methods, and in the same time it is prerequisite for experimental work in contemporary nuclear physics. New knowledge in the field of nuclear physics can be gained only from measurements performed using high quality stable and unstable beams as their results puzzled together provide complete picture of the atomic nucleus. For these reasons, this training event at unstable ion beam facility, unavailable at the RBI and INFN-LNS, was important step towards the full realization of the CLUNA project objectives.
Participation at international conferences
WP6 activities also included participation of the RBI and UoZ research staff at international conferences and workshops on nuclear physics, where they presented results of the research work performed in collaborations with researchers involved in the CLUNA project, as well as on new possibilities for experiments at the RBI nuclear research end station upgraded through the CLUNA project. Attendance of RBI/UoZ researchers to six conferences was planned, but at the end travel expenses for three conferences were covered using CLUNA funds. However, the RBI/UoZ researchers attended some international meetings, schools, conferences and workshops using other funding sources, using these occasions to disseminate results of the CLUNA project and present enlarged research capability and capacity of the RBI nuclear physics research instrumentation.
All the expected objectives of the WP6 were fully achieved: the collaboration between all the four partner research groups is stronger than it was before the CLUNA project, knowledge and experience on experimental techniques and methods for nuclear clusters studies have been spread over all participating researchers, and acquired knowledge and experience have helped in successful realization of all planned activities in other project work packages.
Total cost of the WP6 in the project was 43740 , close to 90% of the planned work package funding.
Potential Impact:
Impact
The immediate impact of the CLUNA project is greatly improved research potential of the RBI/UoZ groups for nuclear physics experimental work. In addition to the improved experimental facility and expertise, the project has a synergetic effect on the scientific cooperation between the project partners and their cooperation with the other nuclear physics groups from Europe. Apart from an increased contribution to existing collaborations, the successful realization of CLUNA provided opportunities to enter new collaborations at both national and European level. The upgraded experimental end station for nuclear physics research at the RBI Tandem Accelerator facility is unique in Croatia and South-East Europe, with large potential benefits to the broader scientific community, to the national and regional universities and wider.
With CLUNA, partnership has been strengthened at several levels with three prominent partner organizations: Universities of Zagreb and Birmingham (UoZ and UoB), and with the Italian National Institute of Nuclear Physics, Laboratory in Catania (INFN-LNS). With all of them RBI had already established cooperation. CLUNA strengthened this partnership, especially through human mobility actions and exchange of know-how. Through CLUNA partnerships between Zagreb and EU groups has been strengthened by more frequent personal contacts, exchange of knowledge and experience between researchers, upgrading of experimental end station at RBI with the aim to serve as research facility for collaboration measurements and via future commonly planned and performed experiments at RBI, INFN-LNS and other European accelerator facilities. Due to overlapping research interest of involved groups and access to upgraded RBI and INFN-LNS facility for all members of the collaboration, partnership between these four research groups will continue after the end of this project. During CLUNA implementation, new partnerships were established with researchers from other R&D organizations, like from University of Huelva in Spain and GANIL and LPC, Caen, France.
All partners benefited from results of this project: RBI obtained more competitive research infrastructure with significantly increased number of external users, INFN-LNS have access to improved low energy accelerator facility and increased number of international users at home facility, UoB obtained a new site for low energy measurements at RBI and additional site for intermediate energy measurements at INFN-LNS, and finally UoZ obtained access to better local site at RBI for research and educational purposes.
RTD capacity and capability at RBI has been upgraded with new researchers employed, training of research staff, improvement of research management, and upgrade of scientific equipment.
New researchers: Three outstanding graduated students were employed. They were nicely incorporated into the RBI nuclear physics research groups. They are all now employed as PhD students on national research grants supported by the Ministry of Science, Education and Sport (MSES). Without CLUNA it would be difficult to attract these young researchers and keep them during the period of uncertainty while waiting for approvals of local funds for hiring new staff.
Training of research staff: Exchange of knowledge, know-how and experience on modern experimental nuclear physics, including measurement methods, interpretation - validation of data, interpretation of experimental data and modeling resulted in a well educated and skilled staff, able to perform complex R&D work required in collaborative projects. Altogether the RBI/UoZ staff spent about 12.5 person-months for training activities at partner organizations and top international research laboratory (GANIL), and staff from partner organizations spent about 10 person-months at RBI and GANIL. Two workshops were held, one at the INFN-LNS and one at the RBI, and one training event at the GANIL Caen, France, resulting with intensive transfer of knowledge and experience. Further, intensive exchange visits program between RBI/UoZ and partners resulted in significantly enlarged knowledge and experience of the RBI/UoZ staff.
Improvement of research management: CLUNA project increased the research management capabilities of the RBI, realized through WP1. Staff from the respective RBI support department assigned to this project visited UoB to exchange know-how and experience in R&D project management. Experience and knowledge on research management acquired both by the RBI researchers and administration during the project implementation are valuable background for future larger projects.
Scientific equipment: the RBI experimental end station for nuclear physics research is fully upgraded according to the project description of work, with some additional improvements which required small additional investment. Upgrade and renewal of the existing nuclear physics experimental end station increased its experimental capabilities. The RBI detection system for nuclear physics research is enlarged with the large silicon detector array for charged particles detection, neutron detector array, associated front-end electronics and data acquisition system. In the enlargement of the RBI experimental capabilities, large part of funds and work has been used for purchase and commissioning of fast neutron detectors. Merging of the neutron detectors with the silicon detector array on improved end station greatly expanded the research topics for future collaborative research. The system is fully operable and in usage for nuclear structure and reaction studies as well as for research in nuclear astrophysics. Availability of helium beams for future research have been secured and new ion beams of 9Be, 10,11B, 13C and 18O are available for experiments at the RBI Tandem accelerator facility. New detection system at RBI is compact and transportable. It can be used for research not only at the local RBI experimental facility, but also at the INFN-LNS accelerator centre and other accelerator laboratories worldwide. The detection system is fully compatible with research equipment of our partners from University of Birmingham and INFN-LNS.
Unique expertise for the region: Enlargement of the capacities for experimental nuclear physics research at RBI significantly improved the scientific and technical infrastructure for this kind of research in the WBC region. Even more of that, after the upgrade of the scattering chamber, renewal of the detection system by inclusion of very thin silicon and fast neutron detectors and development of the new beams, RBI research capacities for nuclear structure and reaction research are competitive with the European small facilities. The RBI experimental end station is the only one of this kind in WBC region. In the broader region, SouthEast and NorthEast Europe covered by the EastWestOutreach Nuclear Physics Network (EWON), the EURONS networking activity of 18 institutions from East Europe, RBI is one of the only six existing facilities which satisfy prerequisites for high quality research (others are Rez, Athens, Debrecen, Warsaw and Bucharest). These facilities are now working together in one of ENSAR (FP7 infrastructure project of European nuclear physics community) work packages.
Reducing brain drain: Increased potentials for high quality experimental and collaborative R&D in the field of experimental nuclear physics increased the desirability by graduate students to join the research activities of the RBI/UoZ group. Students become aware that high quality research can be performed also at Croatian institutions. This helps to reduce the large brain drain from Croatia, improving the national education level, and increase the number of Ph.D. thesis carried out at RBI. The RBI Tandem Accelerator facility is actively involved in educational activities. In partnership with the UoZ, students in physics use the accelerator facility to perform seminars, BSc, MSc and PhD theses. With the upgraded nuclear research end station, possibilities for the expanded educational programmes are opened. Recently University of Zagreb and RBI started joint post-graduate studies in Nuclear Physics. The RBI Tandem Accelerator facility has been used for practical demonstrations and experiments for students. Additional potential users of the facility in educational and applicative activities are other universities with Physics Departments from Croatia (Split and Rijeka), as well as the universities from the WBC region.
Increased opportunities for popularization of science: The RBI Tandem Accelerator facility is open for general public on regular RBI Open Days and for visits of students and pupils. According to our experience modern experimental facilities are very attractive to general public and attract positive interest of general public for research and development activities in general.
The very fact that our four research groups are partners in the FP7 project and our increased communication have very positive influence on strengthening of the collaboration between partner institutions. In the recent period two new proposals for experiments at international experimental facility were approved in which researchers from all partnering institutions involved in the CLUNA project are participating with work power and equipment. Another proposal is submitted to GANIL two weeks ago for expert committee evaluation. Further research projects with participation of all CLUNA partners are planned for the near future, some of them also at the upgraded RBI experimental facility.
Dissemination
Main dissemination activities were grouped within WP7. Objectives of this WP were:
(i) to realize dissemination of knowledge and project results to international nuclear physics community and general public; and
(ii) to present to general public methodology, goals and results of research in nuclear physics, particularly positive influence of this research on today's life of people.
The design and development of web site on activities of the CLUNA project, including some general content on the nuclear reaction and structure studies, was performed during the first project year, and the web site was launched in February 2009, with continuous updating. During the second project year the project web site was enlarged to include pages in Croatian language, written by RBI/UoZ staff with general content on nuclear physics and related research presented on level understandable to high school students, with aim to popularize nuclear physics and science in general.
Exploitation of results
Implementation of WP2 resulted with the availability of helium beams for future research. In addition, expertise has been acquired for the production of new ion beams of 9Be, 10,11B, 13C and 18O at the RBI Tandem accelerator facility. These ion beams are not available only for nuclear physics experiments, but also for interdisciplinary research and services.
In short, the exploitable knowledge of the CLUNA project can be summarized as follows:
1) exploitable knowledge on production of new ion beams can be used in accelerator running services with aim on applications of low energy accelerators. It is know-how available from 2010 owned by RBI,
2) expertise in use of silicon strip detectors can be used in interdisciplinary research and analytical services for material analysis and development of advanced materials. It is know-how available from 2011 owned by RBI,
3) expertise in data acquisition systems can be used in interdisciplinary research and analytical services for running complex experimental instrumentation. It is know-how available from 2010 owned by RBI,
4) exploitable knowledge on measurements with unstable beams including specificities of experimental setup and data analysis will be used in nuclear physics research for general advancement of knowledge in nuclear physics, but also can be used in interdisciplinary research for highy specialized analytical services (for example deposition of long-lived radio-isotope in materials, biological or medical samples etc.). It is know-how available from 2011 owned by RBI,
5) expertise in use of neutron detectors can be used in interdisciplinary research and analytical services for material analysis, development of advanced materials and homeland security (neutron detection from radioactive materials). It is know-how available from 2011 owned by RBI.
In addition, project CLUNA exploitable foreground is commissioned research instrumentation:
1) upgraded experimental end station for nuclear physics research can be used not only for basic research in nuclear physics, but also for interdisciplinary research (astrophysics, materials characterization). Fully upgraded is from 2010,
2) detection system for charged particles can be used for nuclear physics research and interdisciplinary research at RBI, INFN-LNS and other European accelerator facilities from 2010. It is owned by RBI,
3) neutron detection system also can be used for nuclear physics research and interdisciplinary research and applications (material analysis, detection of radioactive materials in homeland security) at RBI, INFN-LNS and other European accelerator facilities from 2010. It is owned by RBI.
Project website: http://zef.irb.hr/cluna
Mailing lists:
all staff: cluna-team@lnr.irb.hr
management staff: cluna-admin@lnr.irb.hr
Coordinator:
Neven Soic
Division of Experimental Physics, Ruder Boskovic Institute
Bijenicka 54, HR-10 000 Zagreb, Croatia
Phone: +38-514-561026, Email: soic@lnr.irb.hr
Project Manager
Stjepko Fazinic
Division of Experimental Physics, Ruder Boskovic Institute
Bijenicka 54, HR-10 000 Zagreb, Croatia
Phone: +38-514-571254
Email: stjepko.fazinic@irb.hr
Representative of INFN-LNS and member of Project Management Board
Pierpaolo Figuera
INFN Laboratori Nazionali del Sud
via S. Sofia 62, I-95123 Catania, Italy
Tel. +39-095-542297
Email: figuera@lns.infn.it
Representative of University of Birmingham and member of Project Management Board
Martin Freer
School of Physics and Astronomy, University of Birmingham
Edgbaston, Birmingham, B15 2TT, UK
Tel. +44-121-4143384
Email: mf@np.ph.bham.ac.uk
Representative of University of Zagreb and member of Project Management Board
Matko Milin
Department of Physics, Faculty of Science, University of Zagreb
Bijenicka c. 32, HR-10 000 Zagreb, Croatia
Tel. +38-514-605545
Email: matkom@phy.hr
