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The NICA project, which includes several accelerators of charged particles, is under construction in the Laboratory of High Energy Physics, Joint Institute for Nuclear Research (JINR), Dubna. Obtaining the required vacuum conditions is one of the key points in implementing the project, because reaching the required ion lifetime at all stages of particle acceleration is what determines the effective luminosity of the experiments in the long run. Currently, modernization of the vacuum system of the injection complex of the LU-20 linear accelerator of light ions, one of oldest accelerators in the JINR, is being carried out and the new HILAC linear accelerator for the acceleration of gold ions in the collider mode of the NICA complex is being installed. At the end parts of the linear accelerators, the residual gas pressure must be approximately 10–5 Pa, which is determined by the maximum amplitude of the RF electric field used for the acceleration of ions.

Nuclotron-based Ion Collider fAcility (NICA) is a new accelerator collider complex under construction at the Joint Institute for Nuclear Research. The facility is aimed at providing collider experiments with heavy ions up to Gold in the center of mass energy from 4 to 11 GeV/u and an average luminosity up to 1 · 10 27 cm -2 s -1 for Au 79+ . The collisions of polarized deuterons are also foreseen. The facility includes two injector chains, a new superconducting booster synchrotron, the existing 6-AGeV superconducting synchrotron Nuclotron, and a new superconducting collider consisting of two rings, each 503 m in circumference. The booster synchrotron and the NICA collider are based on an iron-dominated “window frame”-type magnet with a hollow superconductor winding analogous to the Nuclotron magnet. The status of the serial production and test of the magnets for the booster synchrotron and the development of the full-size model magnets for the NICA collider is presented. The test results of magnets are discussed. The status of the construction of the facility for serial tests of superconducting magnets for the NICA project is described.

NICA is a new accelerator collider complex under construction at JINR. The facility is aimed at providing collider experiments with heavy ions up to Uranium in a center of mass energy range from 4 to 11 GeV/u and an average luminosity up to 1027 cm -2 s-1. The collisions of polarized deuterons are also foreseen. The facility includes two injector chains, a new superconducting booster synchrotron, the existing 6 AGeV superconducting synchrotron Nuclotron, and a new superconducting collider consisting of two rings, each of about 500 m in circumference. The booster synchrotron and the NICA collider are based on an iron-dominated “window frame”-type magnet with a hollow superconductor winding analogous to the Nuclotron magnet. The status of the development of the full size model magnets for the booster synchrotron as well as for the NICA collider is presented. The test results of model magnets are discussed. The status of the creation of a facility for serial tests of superconducting magnets for the NICA project is described.

A high-voltage electron cooling system (ECS) with electron energy reaching 2.5 MeV for the NICA collider is being designed at the Joint Institute for Nuclear Research. The ECS is being developed in correspondence with the available experience in manufacturing similar systems from around the world. The main feature of this design is the use of two cooling electron beams (one beam per collider ring); electrons are accelerated and decelerated by a common high-voltage generator. A conceptual project of high-voltage ECS has been developed. The cooler consists of three tanks filled with SF6 gas under pressure. Two of them contain electron-beam forming systems; each system consists of two electron guns, two electron collectors, and accelerating-decelerating tubes placed in a longitudinal magnetic field generated by a solenoid. The third tank contains a high-voltage generator based on the voltage-multiplying circuit.

In the Laboratory of High Energies at the Joint Institute for Nuclear Research, as part of the NICA-MPD [1] project, tests of two prototypes of HTSC current leads prepared at ASIPP institute (Hefei, China) have been performed [2, 3] to measure electric and heat parameters and to search for structural and physical drawbacks. Based on the experimental results, necessary changes are made in the structure of HTSC current leads of the testing stand for the magnetic element testing of the NICA accelerating complex and its basic setups: the Nuclotron, Booster, and Collider.

NICA is a new accelerator complex being constructed at the Joint Institute for Nuclear Research; the main task of this complex is to perform collider experiments for ion beams up to uranium with energies of up to 3.5 × 3.5 GeV/nucleon. This complex includes an electron string ion source, a 6 MeV/nucleon linear accelerator, a booster, the Nuclotron, and a collider with an average luminosity of 1027 cm2 s−1. The main tasks of the booster are to accumulate up to 4 × 109 197Au32+ ions, to accelerate to 600 MeV/nucleon (sufficient enough energy for completely stripping nuclei), to reduce the requirements of vacuum conditions for the Nuclotron, and to form the necessary beam emittance using an electron cooling system. The specific features of the NICA booster and the requirements for the basic systems of the synchrotron and their parameters are presented in this paper.

The Low Energy Particle Toroidal Accumulator (LEPTA), a positron storage ring with electron cooling, was constructed and put in operation at the Joint Institute for Nuclear Research (Dubna). The storage ring is a generator of directed beams of ortho-positronium (o-Ps) produced upon the recombination of the beam of positrons circulating in the storage ring with a single-pass electron beam. In 2004 the storage ring was put in operation with the circulating electron beam. The source of positrons of the positron injector was tested with a new radioactive source delivered from South Africa. The positron trap was put in operation for electrons. The electron cooling system was tested with a pulsed electron beam. The progress in commissioning LEPTA is described in this paper.

The project of the Low Energy Particle Toroidal Accumulator (LEPTA) is dedicated to the construction of a positron storage ring with electron cooling of positrons circulating in the ring. Such a specific feature of LEPTA automatically enables it to be a generator of positronium (Ps) atoms, which appear in the recombination of positrons with cooling electrons inside the cooling section of the ring. The project has the following goals: particle dynamics in the modified betatron, electron cooling with a circulating beam, positronium generation in flight, positronium physics, and feasibility of antihydrogen generation in flight. All key elements of the ring—the kicker, electron beam injection system, helical quadrupole, septum magnet—have been tested, and the expected design parameters have been achieved for these elements. The construction of LEPTA has been completed, and the circulating electron beam has been achieved. This paper discusses the issues of particle dynamics in such an accelerator, the results of numerical simulation and experimental findings of the research into beam dynamics, measurement of betatron number and beam lifetime.

Low Energy Particle Toroidal Accumulator, which is under construction in JINR, is a storage ring with particle focusing provided by longitudinal magnetic field. The general goals of this installation are electron cooling of positrons, positronium generation and experiments with an intensive positronium flux. Current status of the project realisation is presented. Results of tests of general elements of the ring with modeling electron beam are discussed.

Ensuring the high homogeneity of a magnetic field in the straight solenoid of an electron cooling system is a very important task. In the electron cooling system of the collider in the NICA project, it is planned to use superconducting solenoids for the generation of a longitudinal magnetic field. Using of the superconducting shield is proposed to achieve the required homogeneity of the magnetic field in the cooling section. This article discusses the design of the superconducting shield and presents experimental and numerical studies into the homogeneity of the magnetic field in solenoids with the superconducting shield.

The BETACOOL program, developed by electron cooling group of the Joint Institute for Nuclear Research (JINR), is a set of algorithms based on common format of input and output files. The program is oriented toward simulation of the ion beam dynamics in a storage ring in the presence of cooling and heating effects. The version presented in this report includes three basic algorithms: simulation of root-mean-square (rms) parameters of the particle distribution function evolving in time, simulation of the distribution function evolution using the Monte Carlo method, and a tracking algorithm based on a molecular dynamics technique. The general processes investigated with the program are intrabeam scattering in the ion beam, electron cooling, and interaction with residual gas and an internal target.

The Low Energy Particle Toroidal Accumulator (LEPTA) was commissioned in September 2004 at JINR. The facility is dedicated to studies of particle beam dynamics in a storage ring with longitudinal magnetic field focusing (so called "stellatron"), application of circulating electron beam to electron cooling of antiprotons and ions in adjoining storage ring, electron cooling of positrons, and positronium in-flight generation. The last modes of the ring operation enables setting of numerous experiments with positronium in-flight and generation of directed and "monoenergetic" flux of antihydrogen. The positronium (Ps) atoms appear in recombination of positrons with cooling electrons inside the cooling section of the ring. An assembling of the storage ring LEPTA was completed during year 2004. Peculiarity of the storage ring is focusing of circulating particles with longitudinal magnetic field which covers whole orbit. As result, the particle motion in the ring is coupled in transverse plane. First results of the experimental study of the particle dynamics in the ring performed with circulating electron beam are presented. The beam lifetime was achieved above 20 ms at electron energy of 4 keV and vacuum pressure of 30 mTorr. The limitations of the beam lifetime and the possibility of its enhancement are discussed in the report.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The Low Energy Positron Toroidal Accumulator (LEPTA) is under commissioning at JINR. The LEPTA facility is a small positron storage ring equipped with the electron cooling system. The project positron energy is of 4-10 keV. The main goal of the facility is to generate an intense flow of positronium atoms-the bound state of electron and positron. The focusing system of the LEPTA ring after solenoidal magnetic field remeasurement and correction has been tested with pulsed electron beam by elements. Some resonant effects of beam focusing have been observed. The experiments aiming to increase the life time of the circulating electron beam and test the electron cooling elector beam are in progress. Construction of the pulsed injector of the low energy positrons is close to the completion. The injector is based on 22 Na radioactive isotope and consists of the cryogenic positron source (CPS), the positron trap and the acceleration section. In the CPS positrons from the 22 Na tablet are moderated in the solid neon and transported into the trap, where they are accumulated during about 80 seconds. Then accumulated positrons are extracted by the pulsed electric field and accelerated in electrostatic field up to required energy (the injector as a whole is suspended at a positive potential that corresponds to required positron energy in the range of 4-10 keV). In injection pulse duration is about 300 nsec. The CPS has been tested at the low activity of isotope 22 Na tablet (100 MBq). The continuous positron beam with average energy of 1.2 eV and spectrum width of 1 eV has been obtained. The achieved moderation efficiency is about 1 %, that exceeds the level known from literature. The accumulation process in the positron trap was studied with electron flux. The life time of the electrons in the trap is 80 s and capture efficiency is about 0.4. The maximum number of the accumulated particles is

The Low Particle Toroidal Accumulator (LEPTA) project is under development at JINR. The ring assembling is completed. The test experiments with circulating electron beam are in progress and the results are presented. Assembling and test of the positron injector is started. The program of experiment on directed o‐Ps flux generated at LEPTA is listed in the report. The first experiment that is under preparation presently has the goal to measure p‐Ps life time by interference of ortho‐ and para‐ states of Ps in magnetic field.

The injector of the low energy positrons for accumulator LEPTA is being assembled at JINR. The key elements of the injector have been tested. The cryogenic source of slow positrons has been tested with a test isotope 22 Na of the initial activity of 0.8 MBk. The continuous slow positron beam intensity of 5.8 · 10 3 s −1 with average energy of 1.2 eV and width of a spectrum 1 eV has been obtained. The achieved moderator efciency is about 1%. The accumulation process in the positron trap was investigated with electronux. Th e lifetime of the electrons in the trap, τlife 80 sa nd capture efciency e ∼ 0.4 have been obtained. The maximum number of the accumulated particle was Nexp =2 · 10 8 at the initialux of 5 · 10 6 e − /s. ‚ �ˆŸˆ § ¢¥·I ¥E¸O ¸iμ·± ¨³¶E²O¸´μ£μ ¨´|¥± Eμ· ¶μ§¨E·μ´μ¢ ´¨§±μ° O´¥·£¨¨ ¤²O E¸E - ´μ¢±¨ LEPTA. �·μ¢¥¤¥´μ O±¸¶¥·¨³¥´E ²O´μ¥ ¨ ¸¸²¥¤μ¢ ´¨¥ · iμEO μ¸´μ¢´OI E§²μ¢ ¨´|¥±Eμ· . ˆ¸¸²¥¤μ¢ ´ · iμE ±·¨μ£¥´´μ£μ ¨¸EμI´¨± ¶μ§¨E·μ´μ¢ ¸ E¥¸Eμ¢O³ ¨§μEμ¶μ³ 22 Na, ±E¨¢´μ¸EOO 0,8 Œ±. �μ²EI¥´ ¶EIμ± ³¥¤²¥´´OI ¶μ§¨E·μ´μ¢ ¨´E¥´¸¨¢´μ¸EOO 5,8 · 10 3 c −1 ¸μ ¸·¥¤´¥° O´¥·£¨¥° 1,2 O‚ ¶·¨ I¨·¨´¥ ¸¶¥±E· 1 O‚. "μ²O § ³¥¤²¥´´OI ¶μ§¨E·μ´μ¢ ¸μ¸E ¢¨² 1% μE ¶μ²´μ£μ ¶μ- Eμ± . �·μ¢¥¤¥´μ ¨¸¸²¥¤μ¢ ´¨¥ ¶·μI¥¸¸ ´ ±μ¶²¥´¨O I ¸E¨I ¢ ²μ¢EI±¥ ´ O²¥±E·μ´ I. ‚ ·¥§E²OE E¥ μ¶E¨³¨§ I¨¨ ¶ · ³¥E·μ¢ ²μ¢EI±¨ ¤μ¸E¨£´EEμ ¢·¥³O |¨§´¨ ´ ±μ¶²¥´´OI O²¥±E·μ´μ¢ τlife 80 ¸, OEE¥±E¨¢´μ¸EO § I¢ E e ∼ 0,4, IEμ ¸μμE¢¥E¸E¢E¥E ´ ¨²EII¨³ ·¥§E²OE E ³, ¶μ²EI¥´´O³ ¢ ²μ- ¢EI± I ¶μ¤μi´μ£μ E¨¶ . �·¨ OEμ³ ³ ±¸¨³ ²O´μ¥ I¨¸²μ ´ ±μ¶²¥´´OI I ¸E¨I Nexp =2 · 10 8 ¶·¨ ¶¥·¢μ´ I ²O´μ³ ¶μEμ±¥ 5 · 10 6 e − /¸.

The LEPTA setup (Low Energy Particle Torroidal Accumulator) is being constructed at the Joint Institute of Nuclear Research. The main purpose of this setup is to generate intense fluxes of positronium ions and perform experiments in positronium physics. The main component of the setup is the low-energy positron accumulator with a electronic cooling system. A special feature of the accumulator is that it uses a longitudinal magnetic field to focus a circulating beam. The physical startup of the accumulator was performed in September 2004. The results of the adjustment of the main components of the accumulator, the method for obtaining a circulating beam, and the first results of measurements of its parameters are presented.