A new source of an electron beam with laser heating of the cathode is presented. The general description, the main parameters and the arrangement of the electron beam source are given. The cathode assembly and its operation features are described, which consist in controlling the emission current from the cathode by changing the cathode temperature by controlling the laser heating power. With this method, due to the heat capacity of the cathode and the parts nearby, the time to reach the set current level of the source from the moment the laser power is applied is several seconds. A method is proposed to reduce this time to fractions of a second by forcing the heating power at the beginning of turning on the heating and introducing preheating, and it is also proposed to stabilize the source current by introducing feedback of the heating power control signal with the current signal of the high-voltage source of the electron gun.The source current control range is discussed.

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.

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.

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/).

Several facilities for electron-beam welding have been developed and fabricated at the Budker Institute of Nuclear Physics of the Russian Academy of Sciences. A prototype of the system designed for accurate determination of the welded seam position before the welding process and aiming of the electron beam during the welding process is described. For this purpose, the difference in scattering of electrons (and formation of secondary electrons) by the seam and by the surface of the welded workpiece is used, which allows recording the seam image by scanning with a low-current beam. A block diagram of the prototype and basic algorithms of its operation (both tested and proposed for the future) is given. Results of testing and trial operation of the first prototype of the electron-beam welding facility are considered.

CW 100 keV electron RF gun for 40 mA average beam current was developed, built, and commissioned at BINP SB RAS. The RF gun consists of normal conducting 100 MHz RF cavity with a gridded thermo cathode unit, CW 16 kW generator with GU-92A tetrode in the output stage, and a set of LLRF electronics. The gun was tested up to the design specifications at a test bench that includes a diagnostics beam line. The design features of different components of the gun are presented. Preparation and commissioning experience is discussed. The beam test results are summarized. INTRODUCKTION A 100 MHz RF electron injector was designed and manufactured at BINP for continuous wave (CW) powerful accelerator in RFNC-VNIIEF [1]. This compact accelerator, similar to the type of «RHODOTRON» [2], is designed for continuous production of short electron bunches with energy of 1.5 ÷ 7.5 MeV with power of 300 kW and higher. Each bunch passes through a single accelerating cavity of the accelerator several times. After each pass, the beam is turned in the bending magnets. In order to preserve the transverse dimensions of the electron bunches within the aperture after passing through the bends, the bunches should have small enough energy spread (<1%) and be quite short (<0.2 ns). An advantage of RF guns compared with static guns is the absence of cathode back bombardment with accelerated ions of residual gas ionized by an electron beam. This allows having a long lifetime of the cathodes and operating the gun continuously in the vacuum of 10 -6 ÷ 10 -7 Torr. Also, this enables raising the gun voltage and thus increasing the energy of the electron beam from 3040 keV to 100 keV proportionally to the beam current to the power of 2/3, in-accordance with the Poisson law. Furthermore, calculations showed that the increased voltage in the RF injector in combination with the effect of the longitudinal beam bunching therein provides a reduction in the energy spread of up to 0.3% (rms) in the first passage of the accelerator and the bunch shortening by up to 18 times.

The Novosibirsk ERL is used as a source of electron beams for the powerful Free Electron Laser. It is based on the normal conducting RF structure which operates in CW mode. The third stage of this facility which is the first in the world four-turn ERL has been commissioned recently. More than 90% of electrons were transported to the beam dump, which allowed to increase the average beam current up to 5 mA. The obtained parameters are sufficient to get lasing at the third stage FEL which will be installed at fourth track in the nearest future. In this paper we report the commissioning status and talk about further development of the Novosibirsk ERL and FEL facility.

The Novosibirsk terahertz FEL facility is based on the normal conducting CW energy recovery linac (ERL) with rather complicated lattice. This is the only multiorbit ERL in the world. It can operate in three different modes providing electron beam for three different FELs. The first FEL works for users since 2003. This FEL radiation is used by several groups of scientists which include biologists, chemists and physicists. Its maximum average and peak powers are 500 W and 1MW and wavelength can be tuned from 110 up to 240 microns. The high peak and average powers are used in experiments on material ablation and biological objects modification. The second FEL is installed on the second orbit. The first lasing of this FEL was achieved in 2009. Its radiation has almost the same average and peak powers and is delivered to the same user stations as the first FEL one, but its tunability range lies between 35 and 80 microns. The third FEL will be installed on the fourth orbit. In this paper we report the latest results obtained from the operating FELs as well as our progress with the commissioning of the two remaining ERL orbits. We also discuss possible options for the future upgrade.

The paper presents single-flight beam diagnostic system for VEPP-2000 injection channels. The system includes two types of beam position monitors: secondary emission monitors and image current monitors. Tuning of the system, calibration of monitors, hardware and software of the diagnostic system are described. Main goal of the beam diagnostic system is providing lossless beam transport. To solve such problem one needs to tune up as guide fields as focusing fields of transportation channels. First task - trajectory correction is solved with response matrix inversion by SVD method. Second task - optic function reconstruction - is solved with help of multidimensional fitting of channel magnet structure parameters with minimization mean-square deviation of modelled response matrix from measured one. The paper presents results of practical experience with automated beam transfer and optic functions tuning of injection channels of VEPP-2000 complex.

A superconducting 63-pole wiggler with the average period 34mm designed and fabricated in the Institute of Nuclear Physics in Novosibirsk for Synchrotron Radiation Center Canadian Light Source (CLS) in Canada is described. The maximum field 2.2T in the median plane has been achieved. The liquid helium consumption less than 0.03Lh in operating mode has been reached. It allows refilling liquid helium once a year. In January 2005, the wiggler was installed in the storage ring in CLS and now experiments are carried out. The main parameters of the magnet and the cryogenic systems as well as test results are presented.