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The National Synchrotron Light Source II is a third generation light source, which was constructed at Brookhaven National Laboratory. This project includes a highly-optimized 3 GeV electron storage ring, linac preinjector, and full-energy synchrotron injector. Budker Institute of Nuclear Physics built and delivered the booster for NSLS-II. The commissioning of the booster was successfully completed. This paper reviews fulfilled work by participants.

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 μm; the second at 37 – 80 μm; the third at 5 – 20 μm). 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 μm 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.

The Novosibirsk Free Electron Laser (NovoFEL) is based on a four-turn microtron-recuperator. To ensure its stable operation and radiation generation, it is necessary to provide a stable mode of electron beam recirculation and minimize beam losses on the vacuum chamber wall on all the beam way in the accelerator beamline. To this end it is necessary to know the longitudinal distribution of these losses along the beamline. A system for registration of beam losses was created. The system applies optical fibers placed along the vacuum chamber and nearby it. If local electron beam losses occur somewhere in the vacuum chamber, electrons falling to the vacuum chamber wall cause generation of X- and gamma rays. This radiation in turn originates optical emission in an optical fiber nearby the region of electron “precipitation” on the chamber wall. Then, executing some transformation and processing of the time dependencies of signals from these optical fibers, one can obtain the longitudinal distribution of electron beam losses along the accelerator line in all its four turns.

The Novosibirsk free electron laser is the first multi-turn energy-recovery linear accelerator with three separate laser systems (the terahertz, far-infrared and mid-infrared ones). The facility is well equipped with optical elements and instrumentation available to Russian and foreign users. In this paper, we describe in brief the workstations of the facility and survey selected recent experiments using intense monochromatic terahertz laser radiation, which can be tuned from 90 to 240 μm.