Message to the issue

The fourth stage of commissioning at the NICA complex
has been completed

On 3 February, the longest-ever session in the history of the VBLHEP accelerator complex was completed. The fourth and the most critical commissioning stage was completed, during which the modes of joint operation of all units of the heavy ion injection chain of the collider were tested: a prototype of the specialized heavy ion source KRYON, the linear heavy ion accelerator and two superconducting synchrotrons - the Booster and the Nuclotron.

As a result, a record for Nuclotron intensity of a xenon nuclei beam (up to 10 million nuclei per cycle) has been achieved accelerated to an energy of 3.9 GeV/n and a strategy for obtaining intense beams of heavy ions for subsequent injection into the collider has been developed.

In the course of preparations for the session that started in April, the heavy ion generation modes in the ion source and their acceleration in the linear accelerator were tested; the Nuclotron magnetic-crystalline system was seriously modified and the modes of the cryogenic complex were optimized.

Almost all the systems of the complex have been significantly developed: the cryogenic systems of the superconducting magnets of the Booster and the Nuclotron have been debugged during their joint operation, the electron cooling of xenon ions in the Booster has been adjusted that has resulted in a twofold increase in the intensity of the accelerated beam at the Nuclotron ejection and dynamic correction of the beam orbit has been implemented in Booster (automatically tunable during ion acceleration), the ion recharging modes during the extraction from the Booster have been studied, the operating modes of accelerating high-frequency systems have been optimized, an important stage in the modernization of the vacuum system of the beamline for transporting the extracted Nuclotron beam of the fixed target experimental facilities has been completed, a new diagnostic system of the beamline has been put into operation.

Work has been carried out on heavy ion beams under the programmes of applied and physical research: microcircuits have been irradiated with argon ion beams at the SOCHI station, test samples of structural materials, nuclear photoemulsions and a CR-39 plate have been irradiated with xenon relativistic nuclei, the transition radiation spectra of a diamond sample at different energies and angles of incidence have been taken.

The BM@N unit has been prepared for operation. At two energies, 3.9 and 3 GeV per nucleon, significant statistics have been accumulated at the BM@N facility. It should be noted that it was the first nuclear physics experiment at the accelerator complex in our country to be carried out accompanied by electron-cooled ions.

The implementation of the session programme has required intense coordinated work of the entire laboratory team that has successfully completed the scheduled programme. An essential result is also the accumulated material for the programme of the further development of the injection complex that will allow to achieve the productivity required for the collider.

Directorate of the Accelerator Department of VBLHEP