A. O. Sidorin

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.

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.

Research and design of a new RFQ injector for modernization of the LU-20 drift-tube linac

A new NICA heavy-ion collider is now under construction at JINR. At the same time, the Nuclotron facility is being modernized. A joint team from the JINR, MEPhI, and ITEP are now reconstructing a proton and light-ion injection system. New results of the RFQ linac resonator testing and measurements and RF power load are discussed in this article.

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.

Longitudinal dynamics of 197Au32+ and 197Au79+ 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.

Status of the LEPTA Project

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 th...

An optical comb filter for the stochastic cooling system at the Nuclotron accelerator (Joint Institute for Nuclear Research, Russia)

To carry out longitudinal stochastic cooling of charge particle beams at the Nuclotron of the Joint Institute for Nuclear Research (Dubna), a unique optical comb filter was designed and developed. The designed filter has space-saving size, low insertion losses, and small dispersion. The comb filter tuning was automated using a specially designed software, which made it possible to reduce the tuning time and increase tuning accuracy up to several hertz. The designed filter with automatic tuning was successfully tested in an experiment on deuteron beam cooling. In this work, characteristics of the designed filter are presented and an algorithm of its automatic tuning is considered.

Beam dynamics in the NICA collider rings

Accelerator complex NICA, developed at JINR, will provide an ion-ion (Au79+) collisions at energies of 1-4.5 GeV/u. The collider characteristics and the beam dynamics have been worked out to create appropriate conditions for the collisions of beams and obtaining the required luminosity parameters in the working energy range.

Realization of Positron Annihilation Spectroscopy at LEPTA Facility

The Positron Annihilation Spectroscopy (PAS) unit was created as a part of LEPTA project at JINR in Dubna. Currently works performed in PAS laboratory focus on studies of defects in solid state, especially on studying radiation damages in novel materials and semiconductors as a part of the international project “Novel Semiconductor for Fundamental and Applied Research”. This report aims to present a current status of realization and progress in PAS methods at LEPTA facility at JINR.

Intense ion-beam dynamics in the NICA collider

The problems of intense ion-beam dynamics in the developed and optimized optical structure of the NICA collider are considered. Conditions for beam collisions and obtaining the required parameters of luminosity in the operation energy range are discussed. The restriction on collider luminosity is related to effects of the domination of the space charge and intrabeam scattering. Applying methods of cooling, electron and stochastic ones, will permit one to suppress these effects and reach design luminosity. The work also deals with systems of magnetic field correction and problems of calculating the dynamic aperture of the collider.