At PAC meetings

Flagship project, reports, proposals

The 59th meeting of the Programme Advisory Committee for Particle Physics was held on 22 January at JINR Conference Centre. It was opened by Chairman of the PAC I.Tserruya with information on the implementation of the recommendations of the previous meeting. JINR Vice-Director V.Kekelidze spoke about the resolution of the 134th session of the JINR Scientific Council and the decisions of the Committee of Plenipotentiaries.

The PAC members welcomed the adoption of the new Seven-Year Plan of Development for JINR and the wish of the Institute's Directorate to focus on the implementation of large projects, including the flagship NICA megascience project. Later, at the meeting, several speeches were dedicated to this project.

Deputy Head of the Accelerator Department of VBLHEP Anatoly Sidorin reported on the progress of the Nuclotron-NICA project. For our weekly, he commented, "Over the past year, in accordance with the work schedule, we made quite serious achievements at the NICA accelerator complex. The assembly of two new experimental stations for applied research was completed. The efforts of the Accelerator Department are mainly aimed at preparing the collider for the first technological session; systems are also prepared for extracting the beam from the Nuclotron into the beam transfer channel into the collider. The technological session is a session without a beam; the cryogenic equipment, power system, vacuum system, magnetic system of the collider and energy evacuation system will be tested. Afterwards, as the equipment is prepared, a decision will be made to carry out a session with the beam. The first session with the beam, depending on the results of the technological session, will be held either at the end of 2024 or at the beginning of the next year."

The Committee commended the successful completion of the assembly of the ISCRA and SIMBO applied research stations. In the tunnel, as the building's engineering infrastructure is put into operation, the assembly of NICA collider magnets is currently implemented. In particular, components of the RF1 and RF2 systems were installed and vacuum tests were carried out. The collider's power supply system is ready for startup.

PAC experts specifically noted the personnel training programme in preparation of putting the collider into operation in 2025. Two four-month sessions will be carried out per year. It will require additional resources, including personnel. With the help of automatic systems, control over accelerating systems will be partially transferred to remote control. A training programme will be developed to train operators. From September to December last year, the first course was held at VBLHEP that consisted of 23 lectures on all systems of the NICA complex. More than 30 employees were interested in training.

The PAC took note of the report on the development of VBLHEP infrastructure, including the Nuclotron facility, presented by VBLHEP Chief Engineer Nikolay Agapov. General construction work is under completion in the new buildings of the NICA complex - the collider building and the new compressor station. The staff carries out installation and adjustment of equipment. Full completion of these activities is expected during 2024. The main part of the helium cryogenic equipment has been put into operation and putting the NICA cryogenic complex into operation will be completed in August, 2024. Construction of the NICA Innovation Centre will begin in summer; an entrance and construction site have already been developed for it.

A report on the implementation of the MPD project was presented by collaboration speaker Viktor Ryabov. Production of all components of the MPD first stage detector is proceeding with minimal delays. The time-projection chamber, time-of-flight system and the 40 of the 50 electromagnetic calorimeter half-sectors are currently prepared for installation in 2024. The most important task is still cooling and powering the large superconducting solenoid. At the end of 2023, a temporary cryogenic solenoid cooling system was assembled and tested at -50°C. Cooling to liquid nitrogen and helium temperatures will begin in January. Future progress will largely depend on the readiness of the MPD building's utility systems, including stable power supply and water-cooling systems that should be completely operational by May, 2024. Magnetic field measurements will begin in June 2024 and will take three months. Installation of the carbon fiber support frame and detector subsystems will start in September. Members of the PAC meeting noted that the participants of the MPD collaboration were able to identify opportunities to address critical issues that arise in many aspects of detector design, assembly and in putting it into operation.

At the meeting, progress in the implementation of the BM@N project, presented by collaboration spokesman Mikhail Kapishin, was highly appreciated. The BM@N team's efforts focused on upgrading the detectors, improving the tracking algorithm, calibrating the time-of-flight system and updating event overlaps in the forward detectors. The first processing of the recovery data registered in collisions of xenon and cesium with an energy of 3.8 GeV during the longest fourth session was carried out using the DIRAC system on computers at the Tier1 and Tier2 levels of MLIT JINR. The signals of the Λ-hyperon and K⁰_s-meson were restored and their physical analysis will be carried out. The BM@N collaboration also presented results on the production of protons, deuterons and tritons in argon-nucleus interactions at 3.2 A GeV. The next physical experiment BM@N is expected to be carried out with a xenon beam at a reduced energy of 2-3 A GeV. Once again, members of the PAC focused on the insufficient number of employees to analyze the data obtained.

A report on the updated version of the SPD Technical Project was presented by the leader of the SPD collaboration Alexey Guskov. Compared to the previous version, the size of the detector has been increased in accordance with the permissible load on the floor of the experimental hall. Options for the input electronics of first-stage detectors are also considered and data acquisition and computing systems are adapted accordingly. Project costs have been updated to reflect current prices, as well as availability of materials and equipment. PAC members approved the development of the International Advisory Committee on DAC SPD detectors and progress in developing a collaboration that includes more than 300 scientists from 35 scientific centres. It is also recommended that the DAC SPD implement a thorough review of the updated Technical Design and report back to the next PAC.

A report on the implementation of the SCAN-3 project was presented by Sergey Afanasiev. The goal of the project is the investigation of η-nuclei. During 2020-2023, a time-of-flight system was developed, two neutron counters were assembled, a magnetic spectrometer obtained from the Lebedev Physical Institute was modified and equipped with appropriate electronics, others. In 2024, the participants of the project are going to test and configure the magnetic spectrometer. The PAC recommended extending the SCAN-3 project for three years with an A rating.

A report on the implementation of the ALPOM-2 project was presented by Nikolay Piskunov. The main goal of the project is to measure the analyzing ability of scattering reactions of polarized nucleons on various targets at the highest pulse signals available at the Nuclotron. In recent years, the authors have replaced the hadron calorimeter, have manufactured new drift chambers, have improved the reconstruction of tracks at small angles, have equipped the facility with a new data acquisition system and have developed new software for analyzing experimental data. The participants of the meeting supported the implementation of this experiment, since it will ensure JINR's leadership in the field of polarimetric equipment and research. The ALPOM-2 project has been extended until the end of 2027 with an A rating.

Vladimir Ladygin spoke about implementing the DSS experiment on the internal target of the Nuclotron. PAC members noted significant progress in obtaining experimental data on energy analysis in deuteron-proton elastic and proton-proton quasi-elastic scattering, in the development of deuteron and proton beam polarimetry for NICA, as well as in upgrading the detector for the spin programme at the Nuclotron. It is recommended to extend the DSS project until the end of 2027 with an A rating.

It was also noted that putting the NICA facility into operation in the coming years, as well as the priority of the BM@N, MPD and SPD experiments, may affect the timely implementation of the SCAN-3, ALPOM-2 and DSS projects. In this regard, Directorate of VBLHEP and NICA is recommended to determine a general strategy for the availability of beam time for users for the next 2-3 years. Once such a strategy is determined, the PAC is ready to prioritize and determine the amount of beam time for these and other experiments.

Two proposals for new projects were also made at the PAC meeting. The first, "Fundamental & Applied Linear Accelerator Physics (FLAP) collaboration using relativistic accelerated electron beams" was presented by Anton Baldin. The FLAP collaboration will carry out research at the LINAC-200 linear electron accelerator. The project is aimed at studying the fundamentals of electromagnetic interactions, as well as new opportunities for meeting applied tasks. This is an investigation of the controlled generation of electromagnetic radiation by relativistic electrons using functional materials, research of the characteristics and controlled generation of Cherenkov, synchrotron and transition radiation, the interaction of relativistic electron beams with surface and corrugated structures, production of secondary neutron beams for neutron radiography, as well as testing of new detectors for non-destructive beam diagnostics. The Program Advisory Committee supported the proposal to develop interlaboratory activities at JINR and recommended opening a new FLAP project for the period 2024-2028 with an A rating.

Members of the Committee listened with interest to the proposal to open a new project, HyperNIS+SRC (HyperNuclear Intrinsic Strangeness and Short-Range Correlations), presented by Alexander Averianov. The initial stage of the experimental programme is aimed at studying the lightest neutron-rich hypernuclei. Finding them can be done using a special facility such as HyperNIS. Currently, it includes beam monitor counters, a trigger counter system, a vacuum decay volume, four groups of proportional chambers and two analyzing magnets. The addition of SRC detectors designed to study short-range correlations will significantly expand the physical programme of the experiment. The PAC supported the proposed experiment with hypernuclei at the Nuclotron, plans to expand the facility and recommended approval of this project by the end of 2029 with an A rating.

Next, Elena Rogochaya (ALICE), Evgeny Khramov (ATLAS) and Vladimir Karzhavin (CMS) presented reports on the results obtained in experiments at the Large Hadron Collider. In general, the contribution of the Institute's employees to the modernization of equipment for these experiments, the investigation of physical processes, participation in data processing and preparation of publications was noted. Scientific reports were presented by David Chokheli "Status of the COMET project" and Maria Patsyuk "Preparation of the SRC experiment".

25 reports presented at the poster session by young scientists from BLTP, DLNP, MLIT and VBLHEP were reviewed. The Committee selected the report by Alexey Sheremetiev (VBLHEP) "Development of technology for the production of double-sided silicon microstrip modules for upgrading the NICA BM@N silicon tracking system" for presentation at the meeting of the Scientific Council in February. The next meeting of the PAC for Elementary Particle Physics is scheduled for 17-18 June.

Galina MYALKOVSKAYA,
photo by Igor LAPENKO