Vol 60, No 4 (2017)

The aim of this review is to provide, whenever possible, a complete picture of the evolution of methods and systems for data readout, acquisition, and transfer at experimental nuclear physics setups over recent years for specialists who use electronics in experiments or measurements in applied research. In view of the large body of information this review is divided into two parts; small and geographically distributed systems are mainly considered in the first part. Both parts have a common classification table and common numbering of cited papers and figures.

Experiments on the detection of γ rays generated in the ¹³C(p, γ)¹⁴N reaction at the Novosibirsk vacuum-insulated tandem accelerator were carried out. Owing to the updated detection system, it was possible to measure the energy spread of beam protons and develop a method for long-term stabilization of the slow drift of the beam energy. The measured energy spread was 1.20 ± 0.15 keV, which was only 0.07% of the total beam energy. This makes the tandem accelerator developed by the vacuum-insulated Budker Institute of Nuclear Physics an attractive tool for solving various research and applied problems.

The light yield in samples of a Nd-loaded scintillator was measured. The scintillator composition differed in the solvent (pseudocumene (PC) and a mixture of PC with linear alkyl benzene), the scintillating dye type (РРО or ВРО), and the Nd concentration. The light yield in the PC (PPO, 1.5 g/L), which was approximately 11500 photons/MeV, was assumed to be the standard. The ionizing-radiation sources were ¹³⁷Cs, ²⁴¹Am, and ¹⁰⁹Cd radionuclides. It was shown that the light yield in the scintillator with a Nd concentration as high 30 g/L (~3%) in PC made it possible to attain energy resolution at a level of 3% at an energy of 3 MeV (neutrinoless 2β decay of ¹⁵⁰Nd).

A generator of single square-wave voltage pulses (SSPs) of 5-kV amplitude and the length from 100 ns to 10 μs is described. This generator is intended for testing pulse electrical strength of devices and electronic components of various purposes. SSP is apllied across an investigated object using five forming lines with an impedance of 50 Ω and three switches: a mercury reed relay, IGBT transistors, and an atmospheric-air-filled spark gap. The SSP rise time is less than 5% of the pulse length. The SSP amplitude depends on the generator load and is equal to 50% of the charging voltage in the matched mode, which can be set with an accuracy of 0.01–10 V (depending on the range) within the range of ±10 V to ±10 kV.

The operation of a thyristor switch triggered in the impact-ionization wave mode was investigated. The switch contained two series-connected Т253-800-24 thyristors of the tablet design with a semiconductor- structure diameter of 56 mm. When a triggering pulse is applied to the switch at a voltage rise rate dU/dt of more than 1 kV/ns, the transition time of the thyristors to the conducting state was shorter than 1 ns. It was shown that the maximum amplitude of the no-failure current increases with an increase in dU/dt at the triggering stage. The possible mechanism of the influence of the dU/dt value on the thyristor breakdown current is discussed. In the safe operating mode at dU/dt = 6 kV/ns (3 kV/ns per single thyristor), the switch discharged a storage capacitor with a capacitance of 1 mF, which was charged to a voltage of 5 kV, through a resistive load of 18 mΩ. The following results were obtained: the discharge-current amplitude was 200 kA, the initial current rise rate was 58 kA/μs, the pulse duration (FWHM) was 25 μs, and the switching efficiency of 0.97.

Experiments on the irradiation of a carbon target with СО₂-laser pulses in the free-running mode at a radiation-flux density of 1.3 × 10¹¹ W/cm² and the time-of-flight technique for measuring the characteristics of the plasma ion component are described. The characteristics of the ion component of plasma that expands along the normal to the target and the statistical spread of the mean values were obtained. As a result of the measurements, the energy spectra of the plasma expansion and the partial ion currents at a chosen distance of the plasma drift from the target were reconstructed. The high time resolution of this technique made it possible to reconstruct the escape times of individual groups of ions from a heated region on the scale of the duration of the heating laser pulse.

The results of theoretical and experimental investigations of a large-area accelerator with a new type of output window are presented. With this window, it is possible to increase the current density of the extracted electron beam, reduce the operating temperature of the foil, and extend its service life. A two-level support structure with cooling of each level is used for this purpose. The heat load of the foil mounted on the second level of the support structure that carries the main mechanical load is reduced by partial interception of the thermal power due to direct loss of the electron beam, which is released on the first level experiencing no mechanical load. The current loss at the structural elements of the output window is estimated, and the hydraulic characteristics and foil temperature in the output device are calculated. A higher current density of the beam extracted over the foil is attained in comparison with the conventional design of the support structure.

Quantitative analysis of materials is significant for its potential usage in different areas. In the present study, quantitative analysis for Fe–Cr binary ferroalloys was evaluated by using Energy Dispersive X-Ray Fluorescence (EDXRF) system and the classical α-coefficient equation. The ferroalloys were prepared from powder form of Fe and Cr elements. The ferroalloys were excited by 59.54 keV γ-rays from ²⁴¹Am annular radioactive source in EDXRF and K_α X-ray fluorescence spectra of Fe were analyzed in the binary matrices for determining analyte element Fe. Also, Wavelength Dispersive X-Ray Fluorescence (WDXRF) system was used to compare the concentrations of the analyte. The agreement was found to be quite satisfactory between the EDXRF and WDXRF (≤1.76 relative difference (%) between concentrations), and it should be noted that the classical α-coefficient equation is highly reliable approach for quantitative analysis of ferroalloys. In addition, effective atomic numbers (Z_eff) of alloys were calculated using scattering ratio (R/C) method and fitted to concentrations obtained of alloys for fit equation.

The design of a rocket Langmuir sonde is described. The electrical circuits of the EU are presented and their specific features are considered. Laboratory investigations of the EU were performed. The nonlinearity of each of six channels of amplifiers–converters does not exceed 1%. The range of the sonde-recorded signals is 30 pA–5 μA; the nonlinearity (as a function of time) of the generator-formed potential at the measuring electrode is 1% or less. Bench tests were performed that confirmed the serviceability of the sonde under the conditions of mechanical and thermal loads that occur during a rocket flight. The technical possibilities of the sonde make it possible to monitor the charged component in the lower ionosphere (100–300 km) from a meteorological rocket; in this case, the density variations of the flows of free electrons and positive ions to the measuring electrode relative to their average value may amount to 2 orders of magnitude. In comparison to its analogues, the sonde provides a higher sensitivity of measurements and a higher time resolution and distorts the electric field in the vicinity of the measuring electrode to a lower degree. The electron-energy distribution function can be reconstructed from the current–voltage characteristic up to the energies of epithermal electrons.

Technical solutions for the construction of inertial-type pressure-gradient receivers were developed. The manufactured laboratory prototypes with dimensions of 110 × ∅32 mm and 112 × ∅80 mm have acoustic-pressure sensitivities of 70–80 and 500 μV/Pa, respectively, in a plane wave at a frequency of 100 Hz. The performance characteristics of the hydroacoustic pressure-gradient receivers, which are used in oceanological investigations at frequencies that are substantially lower than 1 kHz, were improved.

The production technology of silicon semiconductor position-sensitive detectors of nuclear radiation with a sensitive area of 24 × 24 × 1.5 mm and eighth current-collecting strips is described. Their current− voltage characteristics are investigated.