The Center for Collective Use “Siberian Center for Synchrotron and Terahertz Radiation” provides users from various organizations with the opportunity to use modern analytical techniques using synchrotron radiation beams for a wide range of research work. At present, the general direction of the development of new techniques is focused on the development of new original approaches to the use of synchrotron radiation.

An Erratum to this paper has been published: https://doi.org/10.3103/S106287382301001X

The X-ray fluorescence (XRF) analysis with using synchrotron radiation (SR) is a powerful technique for resolving elemental composition of the different samples with high sensitivity. This technique is suitable for nondestructive multi-elemental analyses of heavy elements such as rare-earth elements. In this paper, the choice of optimal excitation energies for the determination of the trace amounts of the different rare-earth elements (REEs) from La to Lu by the SRXRF method was discussed. The SRXRF spectra have received at the synchrotron radiation (SR) station using radiation from the 9-pole wiggler on VEPP-4M at the Siberian Synchrotron and Terahertz Radiation Center (SSTRC). As samples the Russian and international standards of magmatic rocks (AGV-1, BCR-1, DNC-1, BIR-1, SGD-1A, and G-2) were used. This powerful technique should be useful for nondestructive analyses of rare-earth and heavy elements in geological, geochemical and archaeological samples as well as industrial materials.

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.

Novosibirsk free electron laser is a tunable source of radiation generating high-power Gaussian beams in MIR, FIR and THz spectral ranges. In this paper we report the transformation of terahertz beams into the beams with prescribed cross-sections and phase distributions, including vector and vortex beams, using diffractive optical elements. Examples of the use of such beams in experiments are given in the paper.

Results of longitudinal X-ray diffraction studies of the structural organization of biological tissues from humans and animals in different physiological states using Russian sources of synchrotron radiation from the VEPP-3 and Siberia-2 storage rings are presented. The X-ray diffraction patterns of mucus and epithelial tissues show many orders of Debye rings at the main spacing of 4.65 (±0.15) nm, which was attributed to proteoglycan systems of the extracellular matrix of different tissues. The periodicity was experimentally shown to be invariable at a nanoscale level in a broad evolutionary framework. The nanostructural transformation of proteoglycan systems was found to be induced by the synergistic effect of high-frequency electrosurgical welding, which is widely used in clinical surgery. Through the lens of statistical physics of polymer networks, proteoglycans can be considered as labile systems capable of modifying adaptation through the formation of reversible chelate complexes with calcium cations.

A unique instrumentation complex that includes wigglers, X-ray position sensitive detectors, diffractometers, and explosion chambers and enables a 73 ps X-ray diffraction time resolution (exposure time) has been developed at the Siberian Synchrotron and Terahertz Radiation Center, a research collaboration operating at the Budker Institute of Nuclear Physics, Siberian Branch of the Russian Academy of Sciences. A number of techniques have been developed and implemented with which nanosecond-resolution investigations of the nucleation and growth dynamics became possible for the first time for diamond and metal nanoparticles under explosion and shock wave conditions. Studies with millisecond resolution of the structural transformation dynamics of chemical reactions, investigations of the kinetics of self-propagating high-temperature synthesis, and obtaining information on the state of catalysts are also among the new possibilities developed.

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.

In this paper, we have performed experimental, analytical, and numerical studies of beams with topological charges of +/- 1 and +/- 2 formed by silicon binary phase axicons (BPAs) with spiral zone structures. The axicons were illuminated with the Novosibirsk free electron laser radiation (a continuous stream of 100-ps pulses at f = 5.6MHz). The cw power of the beams produced reached 30Wand can by doubled via antireflection coating of the axicons. The intensity distribution in the beam cross sections was in good agreement with the Bessel functions and was kept constant within a distance of about L/r approximate to 190 and 100, where the first ring radii of the beams r were 0.9 and 1.5 mm for the Bessel beams of the first and second orders, respectively. Although the characteristics of the beams (Bessel cross section, "diffraction-free" propagation, self-recovery after passing obstacles, and randomly inhomogeneous media) corresponded to the properties of ideal Bessel beams, their spatial Fourier spectrum (the image in the focal plane of the lens) was, instead of an ideal ring, intertwined segments of arcs with phases shifted by pi, the number of which was equal to the double value of the topological charge. This feature can be used, for example, in a demultiplexing unit of a free vortex-wave communication system or for identification of beam topological charge. We also revisited Young's double-slit diffraction and rotation of beams obstructed by a half-plane, previously applied to Laguerre-Gaussian beam characterization, in the case of the Bessel beams. The Young diffraction pattern demonstrated in this case a complicated intensity-phase distribution. It was shown that the Bessel beams formed by BPAs have two important advantages, which can be used in applications, in comparison with other methods of generation, e.g., a combination of an axicon lens with a spiral phase plate. Although the phase jumps of the axicons are designed for a determined wavelength (141 mu m in our case), the BPAs can form the beams at incident radiation with any wavelength, albeit with a reduced diffraction efficiency, and their cross section is the same for any wavelength.

The energy and angular momentum are quantum characteristics of photons. The angular momentum is the sum of the spin and orbital angular momenta. In physical optics, the spin momentum is described as the polarization of light beams, and the orbital angular momentum (OAM) is the rotation of beam along the azimuth. Interest in beams with OAM [1, 2], or "vortex beams," appeared shortly after the creation of lasers and increased after the publication of the article [3]. Vortex beams have been formed and investigated in the spectral range from X-ray to radio waves, but only a few publications are devoted to beams with OAM in the terahertz range (see [4] and references therein). In this paper we describe vortex Bessel beams with an average power of 25 W, obtained on the Novosibirsk free-electron laser (NovoFEL) [5]. Vortex beams were formed from the NovoFEL Gaussian beam transformed by binary phase axicons (BPA) with spiral zone structures (Fig. 1, a, b). The zone boundaries are described with the equation ( / 2 / 2) r p l , where 2 / 3.2 p mm is the

The relaxation times of localized states of antimony donors in unstrained and strained germanium uniaxially compressed along the [111] crystallographic direction are measured at cryogenic temperatures. The measurements are carried out in a single-wavelength pump–probe setup using radiation from the Novosibirsk free electron laser (NovoFEL). The relaxation times in unstrained crystals depend on the temperature and excitation photon energy. Measurements in strained crystals are carried out under stress bar S > 300, in which case the ground-state wavefunction is formed by states belonging to a single valley in the germanium conduction band. It is shown that the application of uniaxial strain leads to an increase in the relaxation time, which is explained by a decrease in the number of relaxation channels.

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.

We describe the development of activity at the Siberian Center for Synchrotron and Terahertz Radiation at Budker Institute of Nuclear Physics (BINP), SB RAS, since 1974, when the history of experiments with synchrotron radiation (SR) in the world was just beginning–there were no dedicated sources of radiation and works can be carried out at several nuclear centers in the world. BINP made a significant contribution to the development of synchrotron radiation sources, and SB RAS institutes did their part for development of SR application to problems of chemistry, catalysis, biology, geology and materials science. The experiments were made at VEPP-3/VEPP-4 installation.