The paper presents the structure and control algorithms of a modular designed high-current current source designed for precision measurement of the quality of the magnetic field in magnetic elements designed and produced in the Budker Institute of Nuclear Physics for modern accelerator facilities. The development of accelerator technologies constantly increases the requirements for the quality of the field of magnetic lenses and bend magnets of cyclic accelerators. New integral lenses with complex laws of field change are being designed. Several magnetic measurement stands are used to adjust and control the field quality of magnetic elements being developed at the Budker Institute of Nuclear Physics (Siberian Branch, Russian Academy of Sciences). One of the main elements of the stand is a precision current source, which makes it possible to obtain a field map in the tested magnetic element at different current levels with errors less than 0.002

The paper describes the magnetic injector system for the SRF “Siberian Circular Photon Source” (SKIF). The results of modeling quadrupole and solenoid lenses, as well as dipole correctors for an injector based on a linear accelerator are presented. These elements should make it possible to transport the electron beam throughout the accelerator without loss. The results of measurements of all produced magnetic elements are demonstrated. The described elements are working normally at the linear accelerator stand.

To measure the spatial distribution of the magnetic field, both single Hall sensors and arrays of Hall sensors are used. In most cases, a one-dimensional ruler is sufficient. The finished device is called a measuring carriage. The rest of the article describes the first stage of its creation. This article consists in Hall sensor rejection, during which the sensors operate under extreme operating conditions (with increased electrical and thermal loads). During this so-called accelerated aging, the changes in the residual stress values, temperature coefficients, nonlinearity, and divergence of the sensitivity coefficient were monitored. This study can serve as a methodological guide in determining the selection criteria for Hall sensors for precision measuring systems. The need for aging sensors was shown to stabilize their long-term characteristics. In addition, the process of rejecting sensors according to the parameters of interest is described.

BINP SB RAS together with RFNC-VNIITF carry out a research in the field of creating new sources of electromagnetic radiation in the THz range. Within the framework of this article, a project of the THz beam-plasma generator based on an electron beam generated by a linear induction accelerator is presented. The article provides generator scheme and describes the main elements of the electron beam formation system. In addition, the results of modeling the beam transport and its cross-section compression are presented. These calculations were performed under the current up to 1 kA and energy up to 1 MeV for the subsequent injection of the beam into the plasma section with plasma density up to 1015 –1016 cm–3. The article also contains the analysis of previous experimental studies results which are connected with the beam-plasma interaction for various beam and plasma parameters. Based on this analysis, a requirement for the ratio of the beam and plasma electron densities was formulated. This requirement should be satisfied for creation of the beam-plasma generator of EM radiation for the range of 0.1–1 THz with a pulse power of several MW.

Results of experiments on loading flat samples of plastic-bonded HMX by a shock wave are presented. Recording is carried out via an X-ray method in which X-ray is triggered by a sensor that responds to the onset of detonation in a sample. The time and place of the onset of detonation and the influence of the initial density of the sample on these parameters are determined. Experimental results are reproduced in finite element calculations. A dependence between the computational model parameters and the initial density of the sample is obtained.

Project of high-power long-pulse sub-THz to THz-band FEL is under development in collaboration between BINP (Novosibirsk) and IAP RAS (Nizhny Novgorod) driven by the linac “LIU” of the new generation forming 5-20MeV/2kA/200 ns electron beam. The aim of this project is to achieve a record sub-GW power level and pulse energy content up to 10-100J at the specified frequency ranges. In the present paper, results of electron-optical experiments on the formation of an electron beam with parameters acceptable to drive the FEL are discussed. Helical pulse undulators were elaborated for pumping operating transverse oscillations of the beam electrons. As a key component of the electrodynamic system of the FEL-oscillator, the possibility of using advanced Bragg resonators based on the coupling of propagating and quasi-cutoff waves, which are capable to provide stable narrow-band generation under conditions of substantial oversize of the interaction space, is analyzed. Results of simulations and “cold” tests of resonators of this type for operation in the sub-THz range with a diameter of more than 20 wavelengths are presented.

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 high-power long-pulse submillimeter-wave free-electron laser (FEL) is developed jointly by the Institute of Nuclear Physics and the Institute of Applied Physics on the basis of the linear induction accelerator complex, which forms electron beams with a particle energy of 5–20 MeV, a current of 2 kA, and a duration of 200 ns. The studies are aimed at achieving power levels of 0.1–1.0 GW and an energy of 10–100 J in pulses of radiation in the indicated range. We present the results of electron-optical experiments, in which electron beams with parameters acceptable for their efficient application in FELs were formed. Helical pulse undulators have been developed for the build-up of operating transverse oscillations of electrons. The possibility to use modified Bragg cavities, which are based on the coupling of propagating and quasi-critical waves and capable of ensuring stable narrow-band generation at significantly large (as compared with the wavelength) transverse dimensions of the interaction space, is analyzed as the key component of the electrodynamic system of a generator. The results of the simulating and cold testing of this type of cavities for operation in the submillimeter-wave range with a channel diameter exceeding 20 wavelengths are presented.

X-ray facilities based on a linear induction accelerator are designed to study of high density objects. It requires the high-current electron beam to obtain a small spot and bright x-ray source using a conversion target. The electrons source in such facilities is injectors capable generate pulses with a duration from tens of nanoseconds to several micro-seconds and a current of several kA. The transportation and focusing of high-current beams into diameter about 1 mm is difficult due to the space charge phenomena. In the similar induction accelerators (AIRIX [1], DARHT [2], FXR, etc.), auto-emission cathodes are used to obtain high-cur-rent electron beams. The use of a thermionic cathode, in compared to auto-emission cathode, provides stable generation of several pulses with a time interval of several microseconds, but makes high requirements on the injector vacuum system: not less than 10 -7 Torr [3].

The work addresses the use of electron beam produced by the linear induction accelerator to generate terahertz radiation pulses of 100 MW power level based on a free electron laser scheme. The beam parameters required for efficient generation are given. The features of transverse beam dynamics when transporting the beam through the linac are investigated. Emphasis is put on the electron injector which geometry and operation parameters mainly determine the beam characteristics at the linac exit. Most of the possible factors contributing to the beam emittance gain in the accelerator are considered. The obtained analytical estimates are compared to the numerical simulation results. The experimental results on compressing and transporting the beam having the electron energy of 5 MeV and the current of 1 kA in the transport system of free electron laser are presented.

The issue of high-current electron-beam transport in the LIA-5 accelerator is discussed. The results of numerical simulation of beam transport in the 15-m-long LIA-5 accelerator channel are presented. The ASTRA macroparticle (PIC) code and two codes developed at the Budker Institute of Nuclear Physics (a code based on the solution of the Kapchinsky–Vladimirsky system of equations (K–V envelope code) and the UltraSAM code implementing the method of boundary integral equations) are used in this simulation. The experimental data agree closely with the simulation results. The electron-beam envelope is reconstructed based on the experimental luminophore data using the K–V envelope code with a genetic algorithm.

In recent years, silicon dioxide nanoparticles have been widely used in medicine and the pharmaceutical industry, however, their effect on the brain has hardly been studied. We assessed the effects of long-term consumption of 5-nm amorphous silicon dioxide nanoparticles (SiO 2 -NPs) by Syrian hamsters infected with the trematodes Opisthorchis felineus on the hippocampus and frontal cortex. Spectroscopic determination of brain neurometabolites, performed using a horizontal Magnetic Resonance Imaging system at 11.7 Tesla magnetic field, has shown that the ratio of the excitatory neurotransmitters (glutamate + glutamine + aspartate) to the inhibitory ones (GABA + glycine) was higher in the animals infected with O. felineus . However, pre-consumption of the SiO 2 -NPs solution prevented this imbalance. In addition, the protective effect of SiO 2 -NPs on the level of myo-inositol and glycine was found. It is concluded that the use of SiO 2 -NPs can neutralize the negative effects of infectious factors on the brain.

A diagnostic has been developed to study the focusing dynamics of a high-power electron beam on a target. The diagnostic uses a pinhole camera to observe bremsstrahlung from the converter target. A data acquisition system yields images of the beam focal spot with a frame duration of 20 ns and an almost unlimited recording duration. The focal spot dynamics of a linear induction accelerator with an energy of 1.5 MeV, a current of 1.2 kA and a pulse duration of 350 ns were studied. The focal spot was found to be disrupted within the first 100 ns of the pulse. Defocusing has a complex 3-D character. The feasibility of additional cleaning of the target using an accelerator pre-pulse was shown. Stable beam focusing for up to 200 ns was demonstrated.

The paper discusses some peculiarities of the design and development of scientific equipment, particularly mass spectrometers, which provide implementation of high standard scientific and technological analytical testing methods.

The fields of the calibration dipole magnet were corrected on the magnetic measurements bench of the INP SB RAS using active and passive corrections, as a result of which, the magnetic field uniformity was improved from 1 × 10–4 to the level of 1 × 10–5.

Проведена корректировка полей калибровочного дипольного магнита на стенде магнитных измерений ИЯФ СО РАН с помощью активной и пассивной коррекций, в результате чего однородность магнитного поля была улучшена с 1 ⋅ 10–4 до уровня 1 ⋅ 10–5.