卷 59, 编号 5 (2016)

A review of laser devices that are currently used to perform hardness evaluation of microelectronic devices that are exposed to heavy charged particles, with respect to local radiation effects is presented. A brief classification of ionization effects in semiconductors caused by single heavy charged particles is provided. The possibility of using focused pulse-laser radiation for research on these effects is validated. A general approach to the construction of test systems that are based on picosecond lasers with sharp beam focusing systems is presented. The technical requirements for the basic modules of such systems are substantiated. The parameters of the domestic PICO-3 and PICO-4 laser test devices are compared to their foreign analogues and the means of their further improvement are given. The technical and operational characteristics of these devices that allow them to be used in various research tasks that require selective (with a submicron spatial resolution) object excitation by ultrashort laser pulses and recording of its response with exact timing of the moment of excitation, as well as for various precise technological operations, are discussed.

The properties of a convergent neutron lens in the form of an assembly of bent glass capillaries have been experimentally investigated. Each capillary is a conical tube with a length of 22.5 cm, an entrance diameter of 0.25 mm, and an exit diameter of 0.17 mm. The spectrum of thermal neutrons incident on the lens entry is formed on the beam of the IR-8 reactor by means of a diamond microcrystalline filter and investigated with a time-of-flight spectrometer. The spatial distribution of the neutron beam at the exit from the lens is measured using the position-sensitive image plate detector. The measured focal length of the lens is 75–80 mm. The possibility of focusing neutrons with an increase in the local beam density at the lens axis by a factor of 4.9 is demonstrated.

A complex of the new electromagnetic calorimeter (ECAL-2) for the VES setup is described. It is composed of 1592 “shashlik” type counters consisting of a set of lead−scintillator plates, high-voltage supplies based on cascade voltage multipliers for FEU-84 photomultiplier tubes, an LED-based monitoring system, a slow control system, and a pulse-height analysis system. The procedures of ECAL-2 calibration and online monitoring are described.

The schematic design is proposed to control the output of high voltage MOSFET switches of a push-pull high voltage pulser for mass spectrometry applications. The design provides a way to form symmetrical opening and closing gating pulses for the output MOSFET transistors. This solution enables one to avoid the case of high through current, which can damage the output transistors of the pulser. Furthermore, the output pulse width can be decreased up to 70 ns while the repetition rate can exceed 100 kHz using the suggested schematic. The performance of the suggested design is proved by experimental testing of a pulser built in our laboratory.

An experimental stand for investigating and testing lightning protection devices for aerial power lines is described. The stand is composed of an oscillation circuit modeling a power line with an industrial frequency of 50 Hz, a voltage of up to 10 kV, and a current amplitude in the circuit as high as 10 kA; a generator of short single current pulses with a voltage of up to 25 kV and a current amplitude of up to 30 kA, modeling a lightning discharge; and commutation, control, and diagnostic systems. The stand is used to investigate elements of multi-chamber arrester systems for protecting high-voltage overhead lines.

The results of an investigation of the energy-density distribution over the cross section of a pulsed ion beam formed with a passive-anode diode in the mode of magnetic insulation and a closed electron drift in the anode–cathode gap are presented. Diodes of two types are studied: with external magnetic insulation (B_r diode) on the BIPPAB-450 accelerator (400 kV, 80 ns) and self-magnetic insulation of electrons (spiral diode) on the TEMP-4M accelerator (250 kV, 120 ns). In the investigated diodes, various processes are used to form anode plasma: a breakdown over the surface of a dielectric coating on the anode and ionization of the anode surface with accelerated electrons (B_r diode), as well as explosive emission of electrons (spiral diode). To analyze the ion-beam energy density, thermal-imaging diagnostics is used with a spatial resolution of 1–2 mm. The energy-density is calculated from the one-dimensional Child–Langmuir relationship. It is shown that a continuous plasma layer is efficiently formed on the working anode surface for all the investigated diodes. The anode-plasma concentration is rather high, and the beam-energy density is limited by the space charge of ions, but not by the plasma concentration. It is found that, when the magnetic field in the Br-diode anode–cathode gap decreases or the electron current in the spiral diode increases, the energy density of the high-power ion beam rises significantly, but the beam homogeneity decreases.

The problem of determining the optical spectra at separate points of images that are recorded with an endoscopic acousto-optical spectrometer is considered. The factors that cause distortions in images and spectra are investigated. Algorithms for calibration of this type of instruments and digital data correction for the sequential elimination of distortions of various types are developed. In a model experiment, it is shown that the proposed algorithm provides a quite high quality of determining spectra at arbitrary points of the field of vision.

Results of the studies of the sensitivity change in the course of the mean-time-between-failures tests of streak tubes produced by the Dukhov All-Russia Research Institute of Automatics, are presented. It is shown that for the correct determination of the lifetime of these streak tubes during accelerated tests, one should take into account the correction function attributable to processes of reversible changes in the sensitivity of the streak tube photocathode. The designed procedure for accelerated tests of streak tubes is described the basic distinction of which from the existing procedures consists in using this correction function.

Four quadrupole lenses based on permanent magnets of the NdFeB material (PMQ) were developed for the imaging section for forming images of the ion-optical system of the PRIOR proton microscope prototype: the effective length of two of them is 144 mm, and the other two are 288 mm long. The field induction at the radius of the lens aperture is 1.77 Т, and the aperture is 30 mm in size. The modular design of the PMQ makes it possible to vary the length of the lenses, compensate for the offset of the magnetic axis from the ion optical axis of the microscope channel, and decrease the variation of the angular position of the magnetic medians. The PMQ magnetic field was adjusted, scanned, and its main characteristics were determined. The 3D mathematical models of the magnetic-field distribution that are obtained as a result of PMQ measurements are intended for the use in calculations of the beam dynamics during adjustment of the ion-optical system of the proton microscope and for attaining the highest spatial resolution. The developed lenses were used in the first experiments on the PRIOR facility.

A hysteresis-free electrically controlled X-ray optical element based on a monolithic bi-domain bimorphic piezoelectric actuator that is made of lithium niobate crystal was proposed and successfully tested in practice. This element is used for electronically controlled adjustment of the angular position of an X-ray optical monochromator in a range of up to 200″ and is characterized by a high relative linearity (up to 98%), repeatability (the repeatability error is no more than 2%), and low control voltages (up to 100 V). The hysteresis- free behavior of the dependence of the angular position of the element on the control element, which demonstrates the high efficiency of the hysteresis-free monolithic bimorphic piezoactuators as controlled elements of X-ray optics, is shown.

A study has been conducted with the goal of comparing the characteristics of TLD-K detectors based on sodium silicate ceramics to the characteristics of monocrystalline lithium fluoride detectors that contain traces of titanium and magnesium (TLD-100), as well as anion-defected aluminum oxide (TLD-500), which are widely used in thermoluminescent dosimetry. Because they are soil-equivalent, SiO₂ detectors are well suited for measuring the absorbed radiation dose in soils. The results of the comparison indicate that TLD-K detectors are preferable to LiF detectors in environmental applications due to the better uniformity of the detector sensitivity in a batch, the wider range of measurable doses, and the lower threshold in determining small doses.

A method for measuring the resonant frequency of a photoacoustic detector (PAD) in the realtime mode in a wide temperature and gas-mixture-composition range is proposed. The method is based on measurements of natural frequencies of the resonance PADs, which are excited using an auxiliary acoustic emitter built into the PAD. The measurement procedure takes ≤0.1 s. When the PAD is filled with air or nitrogen, the high accuracy and reproducibility of the measurement results is experimentally shown. The relative measurement error of the PAD resonant frequency (~1700 Hz) is approximately 6 × 10^–5.

In-situ testing methods are used to investigate the real-time changing process of materials under different mechanical tests. This paper describes a miniature in-situ three-point bending device, which is compatible with the laser scanning confocal microscope. This device integrates a servo motor, a two-stage worm gears reducer with large reduction ratio and two small lead ball screws. It can realize quasi-static loading mode with a wide rate range from 0.1 µm/s to 0.1 mm/s. The microstructure of the specimen can be observed dynamically during the three-point bending test combined with the force-deflection curve. A calibration method was introduced to calibrate the flexibility of the developed device. The bending experiments were carried out for several different materials with known elastic modulus to verify the feasibility of the calibration method. Finally, the in-situ three-point bending test of red copper was performed to verify the function of the device.

An upgraded high-vacuum installation and procedure for studying diffusion of hydrogen in a BT1-0 titanium alloy membrane during irradiation of a sample by an electron beam with an energy of 10-120 keV in the scanning and stationary modes and with simultaneous electrolytic saturation are described. For this purpose, deflecting electrodes intended for scanning the beam are additionally integrated into the installation. The mass spectrum of the residual gases was recorded by the partial pressure sensors with a sensitivity as high as 10^-13 Pa. The diffusion coefficient of hydrogen measured under the scanning action of the electron beam on the titanium membrane is given.