The project of new accelerator complex NICA relating to nuclear and hadron physics require a more powerful longitudinal and transverse cooling that stimulates searching new technical solutions. The new accelerator complex NICA is designed at the Joint Institute for Nuclear Research (JINR, Dubna, Russia) to do experiment with ionion and ion-proton collision in the energy range 1-4.5 GeV/u for studying the properties of dense baryonic matter at extreme values of temperature and density with planned luminosity 1027 cm-2s-1. This value can be obtained with help of very short bunches with small transverse size. This beam quality can be realized with help of stochastic and electron cooling at energy of the physics experiment. The electron cooling system on 2.5 MeV consists of two coolers, which cool both ion beams simultaneously. The Budker Institute of Nuclear Physics (BINP SB RAS) has already built and commissioned the electron cooling system for the NICA booster, and now it develops the high voltage electron cooling system for the collider. The article describes the construction and status of the cooler development.

When creating accelerators and storage-ring installations in a compact space, there is not always enough space for all the necessary magnet elements. In this case, we can reduce the number of correctors if we shunt magnet coils by a special bypass module, which can take some of the current away [1]. This paper describes this type of bypass module, which can recuperate energy taken to the electrical grid.

The Budker Institute of Nuclear Physics has been designing two accelerator facilities of the Mega-Science class [1, 2]. It is planned to use the same bipolar power supplies sources for corrector magnets in both projects. These power supplies must provide an output current of 6 and 12 A and output voltage up to 100 V. Identical power-supply sources will be used both for slow orbit correction and for fast orbit feedback. As a result, the power-supply sources must provide the high stability of output current (at least 0.01%) and adequate bandwidth (at least 1k Hz). The project must allow for the fast replacement of a failed power-supply source.

The Novosibirsk FEL facility has three FELs installed on the first, second, and fourth orbits of the multiturn energy recovery linac (ERL). The first FEL covers the 90–240 μm range of wavelengths at an average radiation power of 0.5 kW with a pulse repetition rate of 5.6 or 11.2 MHz and a peak power of 1 MW. The second FEL operates in the 40–80 μm range of wavelengths at an average radiation power of 0.5 kW with a pulse-repetition rate of 7.5 MHz and a peak power of around 1 MW. These two FELs are the world’s most powerful (in terms of average power) sources of coherent narrow-band (less than 1%) radiation in their wavelength ranges. The third FEL was commissioned in 2015 to cover the 5–20 μm range of wavelengths. The Novosibirsk ERL is the world’s first and only multiturn ERL. Its distinctive features include a normally-conductive 180 MHz accelerating system, a direct current (DC) electrostatic electron gun with a control grid and thermionic cathode, three operating modes of the magnetic system, and a compact (6 × 40 m) design. The Novosibirsk FEL facility has been in operation for users of terahertz radiation since 2004.

The European X-ray Free-Electron Laser (XFEL) was commissioned in 2017. Budker Institute of Nuclear Physics (BINP) participated in the development, production and delivery of the power system for the corrector magnets. Seven types of high-precision power supplies (current sources) to feed the corrector magnets were developed. To ensure high reliability, a “hot-swap” system was developed for the power supplies. About 400 power supplies for the corrector magnets and 50 hot-swap devices have been put into operation. This article presents details of starting up the power system.

Six types of precision stabilized-current sources (power supplies) have been developed to correct the parameters of the electron beam at the European X-ray Free-Electron Laser. Power supplies are designed to feed the windings of corrector magnets with a direct current of up to 10 A. Based on the stability requirements of the electron beam, the permissible output current instability should be 10–5 or less. All power supplies must satisfy the requirements of electromagnetic compatibility with the electronics of the free-electron laser. The circuit and design features of the power supplies are described and the test results are presented

The European XFEL is under construction now in Hamburg [1]. It is a big international project. Budker Institute of Nuclear Physics (BINP) developed, produced and delivered power supplies for corrector magnets of XFEL. A controller for these power supplies was developed. It provides an 18 bits resolution of digital-toanalog converter and 6 channels of precise analog-todigital converter with high accuracy and resolution. A combination of the general-purpose functions with the specific function for power supplies allowed using the same controller for different equipment of corrector magnet subsystem. Here is described the controller, its properties and main applications.

Free electron lasers (FELs) are unique sources of electromagnetic radiation with tunable wavelength. A high-power FEL has been created at the G. I.Budker Institute for Nuclear Physics. Its radiation frequency can be tuned over a wide range in the terahertz and infrared spectral ranges. As the source of electron bunches, this FEL uses a multi-turn energy-recovery linac, which has five straight sections. Three sections are used for three FELs which operate in different wavelength ranges (90–240 μm for the first, 37–80 μm for the second, and 5–20 μm for the third ones). The first and the second FELs were commissioned in 2003 and 2009, respectively. They are used for various applied and research problems now. The third FEL is installed on the last, forth accelerator loop, in which the electron energy is the maximum. It comprises three undulator sections and a 40 m optical cavity. The first lasing of this FEL was obtained in the summer of 2015. The radiation wavelength was 9 μm and the average power was about 100 W. The design power is 1 kW at a pulse repetition rate of 3.75 MHz. Radiation of the third FEL will be delivered to user stations from the protected hall in the near future. The third FEL commissioning results are presented and the current status of the first and second FELs as well as their future development prospects are described.

The Novosibirsk FEL facility has three FELs, installed on the first, second and fourth orbits of the ERL. The first FEL covers the wavelength range of 90 - 240 mkm at an average radiation power of up to 0.5 kW with a pulse repetition rate of 5.6 or 11.2 MHz and a peak power of up to 1 MW. The second FEL operates in the range of 40 - 80 mkm at an average radiation power of up to 0.5 kW with a pulse repetition rate of 7.5 MHz and a peak power of about 1 MW. These two FELs are the world's most powerful (in terms of average power) sources of coherent narrow-band (less than 1%) radiation in their wavelength ranges. The third FEL was commissioned in 2015 to cover the wavelength range of 5 - 20 mkm. The Novosibirsk ERL is the first and the only multiturn ERL in the world. Its peculiar features include the normal-conductive 180 MHz accelerating system, the DC electron gun with the grid thermionic cathode, three operation modes of the magnetic system, and a rather compact (6×40 m2) design. The facility has been operating for users of terahertz radiation since 2004.

Two BINP colliders VEPP-4M and VEPP-2000 e+ecolliders are under operation with the beams feeding from VEPP-5 Injection Complex via newly constructed K-500 beam transfer line. Upgraded injection chain demonstrated ability to provide designed luminosity both to VEPP4M and VEPP-2000 and techniques of reliable operation are under development now. The design and operation experience of Injection Complex and transfer lines are presented. INTRODUCTION Two electron-positron colliders at Budker Institute of Nuclear Physics (Novosibirsk, Russia) are under operation: VEPP-2000 [1, 2, and 3] and VEPP-4M [4]. Both colliders are fed with the electron and positron beams from VEPP-5 Injection Complex [5, 6]. The infrastructure of BINP accelerator facilities are presented in Fig. 1. VEPP-5 Injection Complex and collider facilities are connected with the Beam Transportation Channels (K-500 Channels) [7]. Figure 1: BINP Accelerator Facility layout. INJECTION COMPLEX VEPP-5 VEPP-5 Injection Complex consists of electron gun, 270 MeV driving electron Linac, 510 MeV positron Linac and dumping ring. Damping ring stores and cools down both electron and positron beams for the next extraction to K-500 beam transfer line (see Fig. 2). Repetition rate is decided to be kept under 12.5 Hz due to VEPP-5 operation experience: some subsystems, like injection/extraction system, require more powerful cooling and some radiation aspects should be reconsidered before planned repetition rate increasing. Nevertheless, 1.2·10 of the particles corresponds to 200 mA circulating beam in the Damping Ring – it exceeds VEPP-5 project parameters more than twice [6, 8]. Figure 2: VEPP-5 Injection Complex layout. Table 1: VEPP-5 Beam Production Parameter Value Energy (2016/17 runs) 385 – 420 MeV Electrons storage rate 2·10/s Positrons storage rate 2·10/s Repetition rate up to 12.5 Hz Maximum e extraction: up to 1.2·10 Maximum e extraction: up to 1.2·10 K-500 BEAM TRANSFER LINE The K-500 beam transfer line was turned into operation at BINP in the end of 2015 [7, 8]. This beamline to VEPP2000 facility was designed to the energy of 510 MeV, it has the length of approximately 250 meters to VEPP-2000 side and 120 meters to VEPP-4M side. K-500 and consists of five sections: descent from Damping Ring to K500 tunnel, regular FODO structure in the tunnel both to VEPP-2000 and VEPP-4M, and two lifting to the both collider facilities. The fragment of the transfer line are shown in Fig. 3. ___________________________________________ † d.e.berkaev@inp.nsk.su WEPIK026 Proceedings of IPAC2017, Copenhagen, Denmark ISBN 978-3-95450-182-3 2982 Co py rig ht © 20 17 CC -B Y3. 0 an d by th er es pe ct iv ea ut ho rs 01 Circular and Linear Colliders T12 Beam Injection/Extraction and Transport Figure 3: VEPP-5 – VEPP-2000 beam transfer line (right down corner – view of the beam at the phosphor screen at the end of transfer line). DAMPING RING INJECTION AND EXTRACTION The cycle of injection/extraction in/from Damping Ring consists from several cycles of beam injection and one extraction action. Extraction channels are presented in Fig. 4. They consist from extraction “bridges” and 900 turns: DC powered solid yoke dipole and quadrupole magnets (green and grey correspondingly in Fig. 6), and descending beam line with VEPP-2000/VEPP-4M separation: DC powered dipoles and pulsed quads. Such a mixture of techniques appeared during long (the project started in 1993) and staged construction and commissioning of the VEPP-5 IC. EXTRACTION AND TRANSFER MODES VEPP-5 IC has four modes of operation: electrons and positrons to two directions. Figure 4: Extraction lines from Damping Ring. Thus, one need to configure 12 different switch processes (see Fig. 6). In the simplest cases, only type of particles is changing. For the other cases one need to magnetize ex-traction magnet system using the opposite type of particles first. Nevertheless, the last rule has the exception: for the transfer of the particles to VEPP-4M direction mag-nets 6M1-4 has to be turned off (see Fig. 5a). So it is very important the state before zero current setup. In our case, positron mode to VEPP-2000 was chosen for both transitions from VEPP-2000 to VEPP-4M directions for stable operation. Each single changing of the magnets fields lasts 30 seconds due to parameters of DC power converters and the inductance of their loads. Therefore, the maximum time of mode change is 60 seconds. a) operation with VEPP-4M facility. b) operation with VEPP-2000 facility. Figures 5 a) and 5 b): IC VEPP-5 Operation Modes. All mode switching as a mode saving and restoring are provided with the special designed infrastructure [9] based on CX modular accelerators modular control system [10]. Proceedings of IPAC2017, Copenhagen, Denmark WEPIK026 01 Circular and Linear Colliders T12 Beam Injection/Extraction and Transport ISBN 978-3-95450-182-3 2983 Co py rig ht © 20 17 CC -B Y3. 0 an d by th er es pe ct iv ea ut ho rs Figure 6: IC VEPP-5 extraction matrix of modes. TWO COLLIDERS OPERATION Common cycle based on the current operation experience starts from the positrons to VEPP-4M mode. Ten minutes are enough to fill the facility booster with 60-90 mA of circulating currents (see the Table 2 for BINP accelerator rings parameters comparison). Than VEPP-4M performs own cycle of boosting and injection to the collider. For this time, IC VEPP-5 is switched to VEPP2000 direction and provides the required particles for another collider. Own VEPP-4M cycle lasts about 15 minutes, then, IC VEPP-5 is turned back to VEPP-4M direction but in the electron mode. Than the common cycle repeats. Typical IC VEPP-5 switching modes are presented in Fig. 7. Figure 7: Status page of IC VEPP-5 [11]. Table 2: Comparison of the Number of Particles and Beam Currents for Different BINP Accelerator Rings VEPP5 DR BEP VEPP2000 VEPP3 VEPP4M N/P,m 27.40 22.35 24.18 74.39 366.1 1•109 1.75 2.15 1.99 0.65 0.13 5•109 8.76 10.74 9.93 3.23 0.66 1•1010 17.52 21.48 19.85 6.45 1.31 5•1010 87.59 107.38 99.26 32.26 6.56 1•1011 175.18 214.77 198.51 64.52 13.11 CONCLUSION At the present, Injection Complex VEPP-5 are routinely provide both types of particles to both BINP Colliders with the efficiency up to 80% VEPP-2000 and VEPP-4 colliders are under operation for the experiments according to their scientific programs.

АППАРАТНЫЕ СРЕДСТВА УВЕЛИЧЕНИЯ НАДЕЖНОСТИ СИСТЕМ ПИТАНИЯ КОРРЕКТИРУЮЩИХ ЭЛЕКТРОМАГНИТОВМагнитная система современных ускорительных комплексов требует множества электромагнитов, предназначенных для коррекции положения пучка заряженных частиц.Как правило, каждый корректирующий электромагнит питается от отдельного прецизионного источника питания.Использование большого количества прецизионных источников снижает надежность работы системы питания.Одно из решений, позволяющих увеличить надежность, является проектирование системы питания с избыточностью.Для этого в систему добавляются резервные источники питания и устройства «горячей» замены.В случае неисправности одного из источников питания соответствующий корректирующий электромагнит дистанционно переключается на резервный источник питания, и система продолжает функционировать.В статье описывается аппаратное решение, примененное для увеличения

Novosibirsk FEL facility is based on the first in the world multi-turn energy recovery linac (ERL). It comprises three FELs (stages). FELs on the first and the second tracks were commissioned in 2004 and 2009 respectively and operate for users now. The third stage FEL is installed on the fourth track of the ERL. It includes three undulator sections and 40-meters-long optical cavity. The design tuning range of this FEL is from 5 to 20 microns and the design average power at bunch repetition rate 3.74 MHz is about 1 kW. Recent results of the third stage FEL commissioning are reported.

Novosibirsk free electron laser (FEL) facility contains three FELs operating in the wavelength range 8-240 micron at average power up to 0.5 kW and peak power about 1 MW. Radiation users works at 6 user stations performing biological, chemical, physical and medical research.

The high-power free electron laser (FEL) facility NovoFEL has been created at Budker INP. Its wavelength can be tuned over a wide range in terahertz and infrared spectrum regions. This FEL uses a multi-turn energy recovery linac with five straight sections as a source of electron beam. Three sections are used for three FELs which operate in different wavelength ranges (the first at 90-240 mu m; the second at 37-80 mu m; the third at 5-20 mu m).The first and second FELs were commissioned in 2003 and 2009, respectively. They operate for users now. The third FEL is installed on the fourth accelerator track, which is the last one; the electron energy is maximal here. This FEL comprises three undulator sections and a 40-m optical cavity. The first lasing of this FEL was obtained in the summer of 2015. The radiation wavelength was 9 mu m and the average power was about 100 W. Radiation of the third FEL was delivered to the user stations, and the first user shifts were performed recently. The results of the commissioning of the third FEL, the current status of the first and second FELs and future development prospects are presented. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).