No 3 (2023)

The results of calibration measurements of the proton beam Cherenkov monitor are presented. A good agreement was obtained between the monitor measurements and the readings of the ionization chamber and the plastic monitor. The Cherenkov monitor does not register photons and electrons with energies below 170 keV, which is important for low-energy background suppression.

Precision high-voltage sources have been developed for nuclear radiation detectors (semiconductor detectors, detectors based on photoelectronic multipliers, etc.). Instead of a specialized high-voltage transformer, a common network (~220 V) POL-12012 transformer was used together with a voltage multiplier. The electrical parameters of the units are as follows: range, from 0 to ±2500 V; power, ≤10 W; efficiency, up to 77%; ripples at a load of 2 MΩ (2 kV), 1 mV; conversion frequency, up to 150 kHz; manual/external control; smooth voltage rise/drop; shutdown upon an overload; temperature drift, ≤0.004%/°C; and operating temperature, –40 to +60°C. Implementation: 3U Euromechanics or an autonomous unit of 80 × 80 × 40 mm. The sources are used in a number of experiments and industrial plants, where they provide quality, reliability, a temperature range, and the required functionality.

A high-power source of ultrawideband radiation of subnanosecond duration based on a hybrid antenna with an offset reflector has been developed. At the focus of the reflector, there is an array of 2 × 2 combined antennas excited by a four-channel bipolar voltage pulse former with an amplitude of 60 kV and a duration of 0.5 ns at a repetition frequency of up to 100 Hz. Radiation modes with discrete scanning of the wave beam, as well as with linear, orthogonal, and elliptical polarizations, were implemented. Radiation pulses with a field strength of 40–120 kV/m at a distance of 4.5 m were obtained.

A new method is presented for increasing the coefficient of electron beam extraction into the atmosphere for accelerators with a non-self-sustained high-voltage glow discharge, which is characterized by high-frequency (tens of kilohertz) generation of an auxiliary discharge. An increase in the efficiency of beam extraction into the atmosphere is achieved by using a pulsed auxiliary glow discharge of the orbitron type, also called wire discharge, and by controlling the pulse duty factor of this discharge while stabilizing the average value of its current. Using the example of the accelerator under study, the possibility of increasing the output coefficient by 0.3 relative to the mode with direct current is shown.

The optical scheme and technical characteristics of terahertz planar Michelson interferometer based on surface plasmons are presented. A technique for determination of the complex index of refraction of surface plasmons (ns@=ns@+iks@) from interferograms is described. The paper presents the results of test measurements on flat surfaces with gold sputtering coated by ZnS layers 0 to 3 μm thick with application of the high-power coherent radiation from the Novosibirsk free electron laser at the wavelength λ0 = 141 μm. From the measurement results, the value of the effective permittivity of the sputtered gold surface was found, which turned out to be an order of magnitude lower than that of crystalline gold. Analysis of the energy losses in the plasmonic interferometer made it possible to estimate its dynamic range (106–108 in terms of radiation power) required for measurements on samples with different ns@. Ways to increase the signal-to-noise ratio via optimization of the elements of the optical scheme and detector have also been proposed.

An X-ray image registration system that consists of a detector that contains two microchannel plates (MCPs), an optical lens, and a digital video camera is presented. Images of the K-spectra of Ca, Ti, Mn, Fe, and Co were obtained using an X-ray fluorescence spectrometer with a curved quartz crystal and horizontal focusing by the Johann method. Measurements were performed using detectors with gain coefficients of 106 and 107 and two video cameras with different characteristics and pixel sizes. A high speed of spectrum measurements with acceptable statistics has been achieved. The spectrum measurement was duplicated on a one-dimensional position detector.

The main principles of operation and design features of a wideband receiving system developed at the Institute of Applied Astronomy, Russian Academy of Sciences, are described. This system operates on orthogonal linear polarizations in the 3–16 GHz band with an output-frequency bandwidth of 2 GHz. The results of measurements of the parameters of the receiving system and the characteristics of the RT-13 radio telescope equipped with the receiving system developed are presented.

On the Lake Baikal coastline (near the village of Goryachinsk), an installation for studying the relationships between wave hydrodynamic and electrical processes was tested. The equipment and measurement technique are considered. The results of measurements under various conditions of the wave process are presented. The physics of the phenomenon belongs to the class of hydroelectrokinetic effects. The natural filtration electric field is associated with the movement of the incoming water wave in porous sand. An electric field is formed inside the porous structure of sand when freshwater moves through it.

Within the framework of this work, a new method for tensile fatigue testing of thin microwires and wires has been developed in accordance with GOST 25.502-79. The developed method has been tested on amorphous microwires of composition Fe77.5Si7.5B15 in glass insulation. It has been established that the deformation mode in the stress range from 0 to 700 MPa corresponds to the long-term use of the studied microwires (millions of cycles). In addition, the studied microwires are capable of withstanding hundreds of thousands of tensile cycles at stresses from 700 to 1100 MPa.

One of the problems in the use of closed-cycle cryostats for applied and basic scientific research is the transmission of mechanical vibrations to the sample. This is particularly relevant for Mössbauer spectroscopy and optical research methods since vibrations lead to broadening of spectral lines. This paper presents various engineering approaches to reducing mechanical vibrations on a sample in closed-cycle cryostats, in particular for Mössbauer spectroscopy. The broadening of the spectral lines of the reference absorber, α-Fe foil, was analyzed and a comparison of the spectra of a FeBO3 single crystal of high structural quality before and after updating the cryostat was made. The obtained results can be used to develop new cryostats or improve existing ones.

ELECTRONIC AC VOLTAGE REGULATOR

Built-in microprocessor pulse recording system for a four-channel optical detector system based on 32-bit ARM controllers Milandr 1986BE92QI

IN SITU MECHANICAL TESTING SETUP IN A SCANNING ELECTRON MICROSCOPE