Vol 62, No 3 (2019)

The first results of neutron-flux measurements at the LSM underground laboratory (Modane, France) using a new sensitive method are presented. Neutrons are detected by counting delayed γγ coincidences in the ¹²⁷I(n, γ)¹²⁸I reaction. It is shown that this approach makes it possible to measure thermal-neutron fluxes at a level of 10^–6 neutron cm^–2 s^–1.

The description and main performance characteristics of a fast-acting gated 48-channel charge-to-digital converter module of the EuroMISS readout electronics are presented. This module is designed to construct electronic systems for data readout from multichannel detectors in high-energy physics. The maximum measurable charge is 1000 or 330 pC, the dynamic range is 12 bits, the conversion time is 1.3 μs, and the integral nonlinearity of conversion is 0.05%.

The possibility of using induction sensors for fixing hypersonic particles in time in the simulation of collisions of high-velocity metal particles with targets is considered. A design of the induction sensor for starting the recording equipment in the air atmosphere is presented. Experimental results on the interaction of particles with air were obtained.

The features of the radio-frequency (RF) paths of waveguide CO₂ lasers with a transverse capacitive discharge are considered with the aim of increasing the energy-transfer efficiency and reducing the discharge-ignition instability. The theoretical model of the laser RF path takes the properties of the optical waveguide as a long line into account, as well as the influence of the laser-head housing material and the matching circuit on the parameters of the RF path. The dependence of the laser-pulse energy stability on the Q-factor of the laser internal circuit is shown. The simulation results in the absence of discharge plasma are compared with the experimental data. The RF path was theoretically simulated under the conditions of the presence of discharge plasma, and the dependences of the efficiency of introducing the power into the discharge on the elements of the matching circuit are plotted.

The design of a diamond neutral-particle spectrometer (DNPS) is presented. The DNPS is a part of the neutral particle analyzer (NPA) at the International Thermonuclear Experimental Reactor (ITER). The operating modes of the DNPS in the NPA complex, the advantages of the DNPS, and its limitations are described. The DNPS system includes two diamond detectors that differ in sensitivity by a factor of 9. The energy losses in detector contacts are numerically estimated. The test results for the diamond detector are presented.

A compact neutral particle analyzer that has been modified for studying thermal and suprathermal ions in neutral-beam heated plasma is described. Results of the analyzer calibration performed using an atomic beam are presented. The possibility of adjusting the analyzer channel energies by varying the voltage applied to the acceleration module of the analyzer is tested. The measured ion temperatures and suprathermal-ion spectra are presented for discharges with the neutral beam injection at the TUMAN-3M tokamak.

Deflectors that are based on the Bragg nonaxial anisotropic diffraction in a paratellurite crystal are considered. Practically significant relationships were obtained and factors that limit the diffraction efficiency and the angular scanning range were determined. A review of several new methods for increasing the main functional parameters of deflectors, which were realized in devices, is presented. In particular, a double-crystal deflector scheme is considered, which makes it possible to significantly increase the diffraction efficiency, extend the scanning range, and create a polarization-insensitive deflector. It is shown that the diffraction mode in the second Bragg maximum (with respect of the acoustic amplitude) can be used for bandwidth broadening. It is proposed to use a two-element optimally phased piezoelectric transducer for extending the frequency scanning range.

The onboard data-acquisition system for the new-generation Yak-42D Roshydromet research aircraft is described. The research aircraft is intended for investigating the atmosphere and the underlying surface. The large quantity of scientific equipment installed onboard requires that the tasks of acquisition, synchronization, transmission, and storage of aircraft observation data be performed. The onboard measuring and computing system developed for the research aircraft and the local computer network are described. The solution to the problem of synchronizing the data of high-frequency measurements is presented. The possibilities of using the local network for integrating the measurement systems on board the research aircraft are shown. The principles of organization of a unified data-acquisition system can be used to build measuring systems for any class of mobile laboratory.

A hydroacoustic autonomous receiving system that uses a combined receiver has been developed for carrying out investigations of the vector−scalar structure of acoustic fields under shallow water conditions with a submersion depth as large as 100 m. The acoustic fields are investigated by measuring the acoustic pressure and three orthogonal components of oscillatory acceleration using sensors with a sensitivity of 150−180 μV/Pa. In addition, data on the spatial position of the system from the orientation and depth sensors are synchronously recorded and, together with the data from acoustic channels, are saved to an SD card.

The design and characteristics of the displacement sensor based on a hysteresis- and friction-free Hall-effect transducer are described. The conversion factor is 40 mV/mm at a supply current of 90 mA. The displacement ranges are within the margins of ±1 mm and ±0.4 mm with a deviation from the linearity of less than 1%. The stiffness is 10 g-force/mm and the achieved resolution is 1.25 nm.

A source of low-temperature nonequilibrium argon plasma has been developed on the basis of a special form of the diffusion discharge, that is, a glow discharge on which low-current spark discharges are superimposed. The discharge is created in an argon flow in the form of atmospheric pressure jets. The nature of the current flow in the discharge gap is a steady-state condition of periodic current pulses. The PortPlaSter portable plasma sterilizer has been created based on the plasma source.

An instrument has been developed and manufactured to measure the uniformity of the layer thickness deposited inside ceramic vacuum chambers of electron-beam injection devices (kickers). Using this instrument, it is possible to measure this parameter at an aperture size starting with 1 cm and at different aperture geometries. The measurement range is 0.1−100 µm. The necessity of such measurements is substantiated, various types of sensors are described, and results for some vacuum chambers of the injection kickers in the MAX-IV synchrotron radiation facility (Sweden) are presented.

On the basis of Hall transducers, a three-dimensional scanning microscope with a sensitivity of ~2.5 × 10^–3 G/Hz^1/2 was designed. The dynamic range of the microscope with respect to the magnetic field ranges from 10^–3 to ±3 × 10³ G. The stability of a given magnetic field is better than 10^–5 G. The minimum value of steps when the magnetic field varies stepwise is 10^–3 G. The maximum survey area of the objects under study is 5 × 5 mm². The minimum scanning step sizes are 10 and 1 μm along the Х and Y axes, respectively, for rough and fine displacements of the tables. The maximum scanning size along the Z axis is 25 mm with minimum scanning steps of 10 and 1 μm, respectively, for rough and fine displacements. The microscope allows one to create an instrument function of an arbitrary shape due to a combination of the specified temperature, transport current, a dc magnetic field, and a time-oscillating ac magnetic field. Examples of applying the microscope to investigations of high-temperature BSCCO and YBCO superconductors are presented.