Vol 60, No 6 (2017)

A neutron detector is described, whose operating principle is based on detecting charge-transfer effects of secondary recoil protons produced in hydrogen-containing materials under exposure to primary neutrons. The physical mechanism of the operation of this detector is presented and its sensitivity is determined as a function of the neutron energy. The design of a detector that is insensitive to attendant γ rays is proposed. The serviceability of the detector has been confirmed experimentally. The detector may find application to tests in mixed fields of γ rays and neutrons.

A procedure for spark-discharge purification of a liquid xenon sample with a mass of 55 kg is described. The average lifetime of ionization electrons before capture by electronegative impurities in liquid xenon increased from ≤ 0.1 μs to ≥ 50 μs for an electric field of 50–500 V/cm as a result of the procedure. The xenon purified with this method is intended for use in the RED-100 detector for observation of the process of coherent elastic neutrino scattering off xenon nuclei.

Campbell Mode is a method widely used in nuclear signal processing. In this article, we introduce the design of the new system based on the Campbell integration measurement applied in NFM (neutron flux measurement) systems for ITER plasma diagnose. In this article, we introduce a digital particle flux measurement system based on Campbell integration theory. A subsequent series of experiment are conducted to test the digital Campbell system performance, which proves that the Campbell integration system is competent for the plasma diagnose in ITER.

A multichannel integrated circuit intended for readout and analog preprocessing of signals from multielement photodetectors has been designed and evaluated. It is optimized for use with silicon photomultiplier arrays. The chip includes current-signal and voltage-signal processing channels. Except for the front end, all of the channels are identical. Each of them contains a code-controlled current amplifier, an integrator, two digitally controlled variable gain amplifiers, a filter, a peak detector, an output buffer with a level shifter, an amplitude discriminator, two timers, and a control unit. The device is configured and tuned by uploading data via a serial interface. The chip is part of a chipset that also includes a multichannel analog-todigital converter with a buffer memory and voltage reference. This chipset makes it possible to build a fullfeatured multielement photodetector signal-processing system, as well as signal processing systems for multichannel detectors of other types. The integrated circuit is implemented in the 0.35 μm CMOS process. This paper also describes the features of the circuits of the device, analyzes the parameters of several of its basic units, and discusses the test results.

Designs of grid units with slotted and multiple-aperture configurations of holes that allow an increase in the stability of the current-cutoff process and a reduction in the time to turn the device off in a high-voltage pulse generator with an inductive energy storage were created. Compared to a TGI2-500/20 thyratron, these designs made it possible to reduce the time instability of the instant of the current interruption by factors of 2 and 5 for switches with the multiple-aperture and slotted configurations of the grids, respectively. These constructions allowed the minimum time for disabling a device to be reduced by 25%.

High-voltage high-current inductors are important components of power-supply systems that are based on capacitor banks with a high energy capacity. The main aspects of designing high-current inductors that were obtained via numerical simulation are presented. A harmonic analysis was performed to take the influence of eddy currents on the inductance value and mechanical stresses into account. It was shown that the choice of materials significantly influences the parameters of the inductor. Calculations of the stray magnetic field in a quasi-toroidal assembly of inductors were performed. It is shown that the leakage magnetic field in the far-field zone is two orders of magnitude lower for an assembly of four inductors than for one inductor.

An experimental test setup for investigating arc and erosion processes in gas-filled high-voltage high-current switches is described and some results that were obtained on it are presented. The setup includes a discharge chamber that allows simulation of the process of disconnecting the ring and pin contacts, a capacitive energy storage with a capacitance of 0.11 F and a charging voltage of up to 10 kV, and a remotely controlled gas-supply system. The diagnostic complex includes systems for measuring the discharge current, the voltage across the arc, and the pulse pressure in the chamber, as well as high-speed filming and optical spectroscopy. Experiments with a current amplitude of 30–300 kA can be performed on the test bench. During the first current half-period of 1.0–3.0 ms, the contacts move apart to a distance of 3–4 cm. The arc is cooled via transverse gas blowing at a pressure in the chamber of 0.5–1.5 MPa. A movable contact is displaced due to the pressure of the gas that is pumped into the chamber.

A subnanosecond electron accelerator prototype based on the ARSA small-size accelerator with a gas-filled former (nitrogen ~4 MPa) has been developed and studied. The operation principle of the former involves charging of a short storage line and its discharge to a stepped line with an accelerating tube that generates electrons. The recorded electron-beam current pulse length was t_0.5 = 0.3 ns, the current amplitude was at least 1.5 kA, and the maximum electron energy was ~850 keV.

A device designed for making microholes in ice packs by steaming along with in-situ determination of the physical properties of ice and collection of liquid samples is described. The total intensity of the light that is scattered in the bulk of the ice mass is reflected from the microhole wall surface, as well as resistivity variations of the liquid formed at the bottom of the microhole during the steaming, are measured in the process of deepening the hole.

The design details and parameters of an induction sensor for a linear accelerator that is used to measure the velocity and charge of accelerated particles are described. A theoretical calculation of the voltage picked up from the Faraday cup of the induction sensor versus the particle parameters is presented. The essential feature of this calculation is the fact that the induction-sensor voltage is considered not only as a function of the velocity and charge of a detected charged particle, but also as a function of the coordinate of this particle. The experimental data that characterize the performance of the induction sensor are presented.

Algorithms for processing results of high-speed video recording of the processes of interaction between test objects and barriers are presented. The algorithms make it possible to determine the position of the test object relative to a barrier, as well as the kinematic parameters (the velocity and acceleration) of the points of the test object before, during, and after interaction with the barrier at initial test object collision velocities of up to 120 m/s. The efficiency of the developed algorithms is confirmed by the good coincidence of the results of videogram processing with the results of acceleration measurements by piezoelectric accelerometers.

A plasma-chemical reactor with the coupling of gas-discharge processes has been developed. These processes combine arc evaporation of titanium in a nitrogen-containing plasma and ion-plasma sputtering of copper with the formation of copper vapor. Experiments were carried out on the deposition of superhard nanostructured TiN−Cu composite layers.