Vol 87, No 5 (2023)

A superconducting undulator with a period of 15.6 mm and a field of 1.2 T created at Budker INP SB RAS was tested in its own cryostat based on indirect cooling with zero helium consumption. The report presents the main characteristics and design features of the magnetic and cryogenic systems of this insertion device. The results of measurements of the magnetic field are presented and the features of the operation of the cryogenic system in various modes are shown.

We described a method of magnetic field correction for a superconducting undulator with neutral poles manufactured in the INP, as well as a mathematical apparatus predicting additional power currents for magnetic field correction. When correcting the field and orbit inside the undulator, the main windings of the undulator are used, grouped into separate groups and powered by additional currents. The test of this correction scheme was carried out, as well as a comparison of theoretical and experimental data of the measured magnetic field and calculated phase errors. In the SPECTRA program, the SI spectra were calculated before and after correction.

The project of a submillimeter free electron laser (FEL) based on a relativistic electron beam (REB) generated in a linear induction accelerator (LIA) was proposed at the BINP SB RAS together with the IAP RAS. According to our theoretical analysis, the electron beam generated in the LIA (energy \({{E}_{e}} = 5{\text{--}}10\) MeV, current \({{I}_{b}} = 1{\text{--}}2\) kA, normalized emittance \({{\varepsilon }_{n}}\) ~ 1100 π · mm · mrad) is a suitable driver for generating sub-GW pulses of coherent EM radiation in submm range (0.3–1 THz). The main proposals for the creation of the FEL based on the electron beam generated in the LIA are presented, the main project tasks are outlined, and the proposed methods for their solution are described. The results of electron-optical experiments on the formation of an electron beam intended for FEL applications are presented.

The superconducting undulator with 15.6 mm period and 1.2 T magnetic field described in this article has 8 mm magnetic gap. The magnetic measurements system in such conditions required using of special tube (ante-chamber) inside of undulator magnetic gap. The thermal insulation between cold magnet and this measurement tube does not allow to have stable temperature along this tube length. The temperature range into this tube is 70–300 K. Hall probe measurements in this case are a rather complicated problem. The features of the method of measurement and processing of results are described.

We show that the introduction of powders-modifiers into a polymer matrix in an amount of less than 1 wt % leads to an increase in the strength characteristics and resistance to cyclical loading with a force of 50–1600 N and a frequency of 2 Hz of more than 3 million cycles.

We proposed to use neural networks to solve the problem of flat-field correction. We described the process of selecting parameters of a deep convolutional neural network to solve the flat-field correction problem with the instability of an empty beam, describes the training of this network, and checks its operability on the generated data. The developed method was tested on data obtained both on laboratory X-ray sources and synchrotron sources.

Weakly conductive ceramics based on barium aluminate have been synthesized and investigated. When fired in an oxidizing medium monophase ceramics with a maximum compressive strength of 678.5 MPa and a density of 3.78 g/cm³ were obtained. The introduction of conductive additives into the composition makes it possible to increase the specific electrical conductivity of ceramics to 1.05 · 10^–4 S/cm (at 300°C).

Synchrotron studies of the features of the dynamics of phase formation in a mechanically activated 3Ti + Al powder mixture during the implementation of high-temperature synthesis under conditions of volumetric ignition by induction heating are carried out. The effect of the time of preliminary mechanical activation treatment of the initial mixture (1, 3, 7 minutes) on the macrokinetic parameters of synthesis was experimentally investigated.

The elemental and mineral composition of loose sediments from the Kan-i-Gut mine-cave (Central Asia) was compared. The obtained concentrations of Mn, Fe, and Zn agree with the minerals determined in the composition of samples from the middle and lower horizons. Increased concentrations of Y, as well as the correlation of this element with As in the researched samples were revealed, which gives grounds to assume the presence of yttrium arsenates in the loose formations. The mineral associations found in the mine-cave indicate the formation of the original karst cavity during sulfuric acid speleogenesis. The mineral gergeite was identified in this site for the first time.

A study has been made for the first time on the element composition of both the plants of three species, growing in the Chuyskaya Basin of Altai Mountain, and the samples of soil from their habitat using the method of X-ray fluorescence analysis, involving synchrotron radiation (SR-XRFA). The accumulation of elements depends on plant species, life form and growing conditions. The data obtained on the elemental composition of plant samples and soils can be included in databases.

An overview is given of works on two experimental installations that implement large-orbit gyrotrons (LOG) operating in the sub-terahertz frequency range at high harmonics of the electronic cyclotron frequency. At the installation of a pulsed LOG (80–100 keV/0.7–1.0 A), a radiation source with a frequency of 1 THz with a kilowatt output power level is being developed, which is planned to be used in plasma applications. A continuous subterahertz LOG (30 keV/0.7 A) is being created as a prototype of a universal multi-frequency source for spectroscopic applications. Complex electrodynamic systems are also described, designed to increase the selectivity and efficiency of excitation of high cyclotron harmonics in these devices, as well as to ensure the tuning of the generation frequency.