Beam-cooling methods in the NICA project

The Nuclotron-based Ion Collider Facility (NICA) is a new accelerator complex under construction at the Joint Institute for Nuclear Research (JINR) for experiments with colliding beams of heavy ions up to gold at energies as high as 4.5 × 4.5 GeV/u aimed at studying hot and dense strongly interacting nuclear matter and searching for possible indications of the mixed phase state and critical points of phase transitions. This facility comprises an ion source of the electron-string type, a 3-MeV/u linear accelerator, a 600-MeV/u superconducting booster synchrotron (Booster), a Nuclotron (upgraded superconducting synchrotron with a maximum energy of 4.5 GeV/u for ions with the charge-to-mass ratio Z/A = 1/3), and a collider consisting of two vertically separated superconducting rings with an average luminosity of 10²⁷ cm^?2 s^?1 in an energy range over 3.0 GeV/u. Beam cooling is supposed to be used in two NICA elements, the Booster, and the collider rings. The Booster is intended for the storage of ¹⁹⁷Au³¹⁺ ions to an intensity of about 4 × 10⁹ particles; their acceleration to the energy 600 MeV/u, which is sufficient for the complete stripping of nuclei (an increase in the injection energy and the charge state of ions makes the requirements for vacuum conditions in the Nuclotron less stringent); and the formation of the necessary beam emittance using the electron cooling system. Two independent beam-cooling systems, a stochastic one and an electron one, are supposed to be used in the collider. The parameters of the cooling systems, the optimum mode of operation for the collider, and the arrangement and design of the elements of the systems are discussed.     

Status of NICA complex at JINR

New scientific program is proposed at Joint Institute for Nuclear Research (JINR) in Dubna aimed a study of hot and dense baryonic matter in the wide energy region from 2 GeV/amu to √s _NN = 11 GeV, and investigation of nucleon spin structure with polarized protons and deuterons maximum energy in the c.m. 27 GeV (for protons). To realize this program the development of JINR accelerator facility in high energy physics has started. This facility is based on the existing superconducting synchrotron—Nuclotron. The program foresees both experiments at the beams extracted from the Nuclotron, and construction of ion collider—the Nuclotron-based Ion Collider fAcility (NICA).     

Longitudinal dynamics of <Superscript>197</Superscript>Au<Superscript>32+</Superscript> and <Superscript>197</Superscript>Au<Superscript>79+</Superscript> ions in NICA injection chain

The main objective of the NICA project developed at the Joint Institute for Nuclear Research (JINR) is to conduct experimental studies with colliding heavy ion beams in an energy range of 1–4.5 GeV/nucleonucleon with luminosity on the level of 1 × 10²⁷ cm⁻² s⁻¹. In this paper the operation regime of the collider injection chain providing the bunch with experimentally desirable parameters at the output of the Nuclotron is considered for gold ions as an example.     

On the development of an ion-beam stochastic cooling system for the nuclotron superconducting accelerator complex

The Joint Institute for Nuclear Research (JINR) initiated the creation of a unique heavy-ion collider, the Nuclotron-based ion collider facility (NICA), which is planned to be put into commission in 2016. According to the calculation data, the collider luminosity, which should be kept at a record high level of 10²⁷ cm^?2 s^?1, will gradually decrease, mainly due to intrabeam scattering. To maintain luminosity at a high level, it is necessary to include a cooling system in the base project of the accelerator. Among the two cooling methods (electron and stochastic) most frequently used for heavy ion beams, stochastic cooling seems more attractive. However, there has been a lack of experience in the development and commissioning of such systems in Russia. For this reason, an experiment on stochastic cooling on the Nuclotron accelerator is being prepared to explore the technology and possibilities of this method. In this work, the method of stochastic cooling, the technique for calculating the cooling dynamics, and the experimental setup under development are briefly described.     

Progress in development of Nuclotron accelerator complex

The Nuclotron superconducting synchrotron was constructed in 1987–1992 [1]; it is the world’s first synchrotron based on fast cycling “window frame” electromagnets with a superconducting coil. For a design field of dipole magnets of 2 T, the magnetic rigidity is 45 T m, which corresponds to the energy of heavy nuclei (for example, gold) of 4.5 GeV/nucleon. The Nuclotron accelerator complex is currently being upgraded (the Nuclotron-M project); this upgrade is considered a key part of the first stage of fulfilling the new Joint Institute for Nuclear Research (JINR) project: the Nuclotron-based Ion Collider fAcility and Multi-Purpose Detector (NICA/MPD). The most important task of this new project is the preparation of basic Nuclotron systems for its reliable operation as part of the NICA accelerator complex. Basic results of activity on the project, which started in 2007, are presented and the results of the last Nuclotron runs are analyzed.     

NICA at JINR: New prospects for exploration of quark-gluon matter

A new scientific program is proposed at the Joint Institute for Nuclear Research (JINR) in Dubna aimed at studies of hot and dense baryonic matter in the wide energy range from 2 GeV/u kinetic energy in fixed target experiments to $\sqrt {s_{NN} } = 4 - 11$ GeV/u in the collider mode. To realize this program the development of the JINR accelerator facility in high-energy physics (HEP) has been started. This facility is based on the existing superconducting synchrotron??the Nuclotron. The program foresees both experiments at the beams extracted from the Nuclotron, and the construction of a heavy-ion collider??the Nuclotron-based Ion Collider fAcility (NICA) which is designed to reach the required parameters with an average luminosity of L = 10²⁷ cm^?2 s^?1.     

Vacuum requirements for the booster of NICA accelerator complex

This paper presents the results of a calculation of ¹⁹⁷Au³²⁺ ion beam losses as they interact with atoms and molecules of residual gas in the acceleration chamber of the booster vacuum system of the NICA accelerator complex [1].     

System of quench detection in superconducting magnets of the nuclotron accelerator complex

A new system for quench detection in windings of superconducting magnets has been created for the Nuclotron synchrotron during the period from 2007 to 2012 during the course of preparing the accelerator for its work as part of the injection chain of the NICA heavy-ion collider and as a source of relativistic heavy ions for baryonic matter in the Nuclotron (BM@N) experiment. The results of testing the system components and its trial operation during the accelerator runs are given.     

Development,creation, and startup of the DC-110 heavy ion cyclotron complex for industrial production of track membranes

The DC-110 heavy ion cyclotron for industrial production of track membranes has been developed and created at the Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research. The cyclotron is equipped with an electron cyclotron resonance ion source operating at a frequency of 18 GHz. The accelerator complex was put into operation in 2012 and ⁴⁰Ar⁶⁺, ⁸⁶Kr¹³⁺, and ¹³²Xe²⁰⁺ ion beams with a energy of 2.5 MeV/nucleon and intensity of 13, 14.5, and 10.5 μA, respectively, were produced. Irradiation of a polymer film was carried out on a specialized channel and track membranes with a high uniformity of pores were obtained. The DC-110 accelerator complex can produce up to 2 million square meters of track membranes per year.     

Beam transportation lines for the NICA project

A heavy-ion collider, i.e., the Nuclotron-based Ion Collider Facility (NICA), is being developed at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. The aim of this project is to construct a new accelerator complex for conducting experiments with colliding ion beam (at the first stage of the project) and with polarized proton and deuteron beams (at the second stage). The NICA accelerator complex will consist of two linear accelerators, two synchrotrons, two collider rings, and beam transportation lines. The magnetic lattice and diagnostic and correction systems for the NICA beam transportation lines are described in this report.     

Correctors’ Magnets for the NICA Booster and Collider

Physics of Particles and Nuclei Letters - The NICA accelerator complex will consist of two injector chains, a new 600 MeV/u superconducting booster synchrotron, the existing superconducting...     

Measurement of the magnetic-field parameters of the NICA Booster dipole magnet

Serial assembly and tests of dipole and quadrupole magnets of the NICA Booster have started at the Laboratory of High Energy Physics of the Joint Institute for Nuclear Research (JINR). The accelerator is fitted with Nuclotron-type magnets with a superconducting winding and an iron yoke for shaping the needed magnetic field. The design of magnets for NICA was optimized (based on the experience gained in constructing and operating the JINR Nuclotron) for the production of magnetic fields of the required configuration in terms of the beam dynamics in the accelerator and the collider. Measurements of parameters of the field of each magnet are expected to be performed in the process of assembly and testing of each module of the magnet-cryostat system of the NICA Booster and Collider. The results of magnetic measurements for the NICA Booster dipole magnet are presented.     

Concept of a coming accelerator complex and design study for heavy ions and intense protons

It is emphasized that a coming accelerator complex should be designed by wide application of beam manipulation. On the basis of this opinion, conceptual designs of two kinds of accelerator complexes of a 30 GeV/nucleon uranium-ion collider and of an intense 30 GeV proton accelerator are studied independently of each other. Moreover, it is shown from these designs that an accelerator complex with accelerator parameters common to both is possibly designed with the help of good beam manuipulation if mutual concessions of beam parameters of heavy ions and of intense protons are accepted. The optimum accelerator complex consists of at least three synchrotrons and three dc rings. The expected beam performance is 450 MeV/nucleon and 30 GeV/nucleon for uranium ions as a typical example of heavy ions, and 150 A below 2.7 GeV and 10 A below 30 GeV for intense protons.     

Projects of Nuclotron modernization and Nuclotron-based ion collider facility (NICA) at JINR

One of the basic facilities at the Joint Institute for Nuclear Research (JINR) in Dubna is the 6 A GeV Nuclotron, which has replaced the old weak focusing 10-GeV proton accelerator Synchrophasotron. The first relativistic nuclear beams with the energy of 4.2 A GeV were obtained at the Synchrophasotron in 1971. Since that time, relativistic nuclear physics has been one of the main directions of the JINR research program. In the coming years, the new JINR flagship program assumes the experimental study of hot and dense strongly interacting QCD matter at the new JINR facility. This goal is proposed to be reached by (i) development of the existing Nuclotron accelerator facility as a basis for generation of intense beams over atomic mass range from protons to uranium and light polarized ions, (ii) design and construction of the Nuclotron-based heavy Ion Collider fAcility (NICA) with the maximum nucleon-nucleon center-of-mass collision energy of √s _NN = 9 GeV and averaged luminosity 10²⁷ cm⁻² s⁻¹, and (iii) design and construction of the Multipurpose Particle Detector (MPD) at intersecting beams. Realization of the project will lead to unique conditions for research activity of the world community. The NICA energy region is of major interest because the highest nuclear (baryonic) density under laboratory conditions can be reached there. Generation of intense polarized light nuclear beams aimed at investigation of polarization phenomena at the Nuclotron is foreseen. The text was submitted by the author in English.     

Heavy ion linear accelerator with high-frequency quadrupole focusing

Based on results of works on the NICA/MPD (Joint Institute for Nuclear Research, Dubna) project, the possibility of designing a heavy ion linear accelerator with high-frequency quadrupole focusing both in the input part and in the main part of the accelerator is shown. Parameters of the linear ¹⁹⁷Au³¹⁺ ion accelerator are presented. Special attention is paid to technical questions of calculating, designing, manufacturing, and tuning the accelerator.     

Magnetic system of a superconducting separated-sector cyclotron for hadron therapy

The development of a cyclotron magnetic system based on superconducting sector magnets is discussed. The cyclotron is conceived as a booster accelerator of a source of ¹²С⁶⁺ ions with energy of 400MeV/nucleon for the purposes of hadron therapy. The results of preliminary investigations aimed at developing such a facility have been reported in our previous papers. In this paper, we consider various configurations of the booster’s magnetic system for various field levels. We also analyze the effects of the positions and shapes of superconducting coils on the magnetic field and select the optimum configuration for the cyclotron’s magnetic system.     

Coherent instabilities in the booster and collider of the heavy ion accelerator complex NICA

In the first part some knowledge about the coherent instabilities in cyclic accelerators and storage rings necessary for the analysis of the collective effects in the heavy ion collider NICA is given. The second part discusses the possibilities for arising of coherent instabilities in the booster and in the collider of the NICA complex. Both coupling impedances and instability thresholds and growth rates have been estimated for single and coupled bunches. Parameters of the beam feedback system for damping of the instabilities have been analyzed. The investigation has been performed at the Veksler and Baldin Laboratory of High Energy Physics, JINR.     

Investigating the adiabatic beam grouping at the NICA accelerator complex

The NICA complex comprises the Booster and Nuclotron synchrotrons for accelerating particle beams to the required energy and the Collider machine, in which particle collisions are investigated. The experimental heavy-ion program deals with ions up to Au⁺⁷⁹. The light-ion program deals with polarized deuterons and protons. Grouping of a beam coasting in an ion chamber is required in many parts of the complex. Beam grouping may effectively increase the longitudinal emittance and particle losses. To avoid these negative effects, various regimes of adiabatic grouping have been simulated and dedicated experiments with a deuteron beam have been conducted at the Nuclotron machine. As a result, we are able to construct and optimize the beam-grouping equipment, which provides a capture efficiency near 100% either retaining or varying the harmonic multiplicity of the HF system.     

Stochastic Cooling in the Startup and Project Configurations of the NICA Collider Equipment

The stochastic cooling system is a key element of the NICA accelerator–collider complex. The dependence of the luminosity on the β function at the interaction point is investigated, the main parameters of the system are substantiated, and the equipment mix for the startup and project modes of collider operation is described.     

Detector based on microchannel plates for monitoring space-time characteristics of a circulating beam at Nuclotron

In the framework of the NICA project preparation and experiments with the extracted Nuclotron beams, the development of an advanced system of circulating-beam diagnostics based on microchannel plates is presented. The detector prototype that has been developed, created, and tested on Nuclotron beams during four runs allows the space-time characteristics of a beam to be measured within a range of singly charged ion intensities from 10⁶ to 10⁹, which is not covered by the existing measuring tools.