Instruments and Experimental Techniques最新文献

The possibility of creating a simple and cheap spatial light modulator based on a liquid crystal matrix of a personal computer display is considered and implemented.

On the basis of a three-phase horizontal flowmeter with a nominal diameter DN 100, options for designing and creating relatively simple two-phase flowmeters without devices for measuring the average density of a mixture of low-viscosity flows, e.g., water–gas, are proposed using only conical narrowing devices (NDs) of various sizes, which are characterized by such features as the crisis of the hydraulic resistance in NDs and various quantitative characteristics that describe this crisis. A calculation and experimental method is proposed that demonstrates the principal possibility of finding the gas volume fraction β using pressure drops ∆Р at both NDs. An unusual calculation model is proposed based on the need to know a pair of measured pressure drops’ ∆P values and preliminary experimental calibration dependences ∆P(β) for both NDs at different volumetric liquid flow rates Q₁, and it is shown that the resulting errors in determining Q₁ and β are quite acceptable for practice in some cases. A universal design of a two-phase flowmeter has been proposed and created, thus allowing the operation with liquid–gas flows not only of relatively low viscosity, but also of comparatively high viscosity, as well as with two-phase liquid flows. This flowmeter is based on a combination of a pair of NDs and a tuning fork densitometer, thus providing a measurement accuracy acceptable for practice. A variant of a three-phase oil–water–gas flowmeter is also presented.

An original transmission line pulse setup has been presented. This test setup allows to measure quasi-static I–V curves of the semiconductor devices and electrostatic discharge protection and investigate the electrostatic discharge robustness of the integrated circuits. The setup allows to perform both destructive and nondestructive tests. The designed test setup allows to perform transmission line pulse test using 100 ns pulse with current peak value up to 10 A according to the IEC62615 international standard.

A radiophysical complex is considered for studying the influence of the propagation environment on orthogonally linearly polarized electromagnetic waves with horizontal and vertical polarizations. The radiophysical complex made it possible to register the quadrature components of the received orthogonally polarized signals and to calculate the amplitudes and phases of the signals and their polarization characteristics from them. Electromagnetic waves were emitted with equal amplitudes, initial phases, and wavelengths from two points spatially separated in the horizontal plane. In the framework of the two-vibrator scattering model, an analytical expression for the scattering operator is obtained, which makes it possible to estimate the differential characteristics of the propagation medium. The relationship between the model parameters and the obtained experimental estimates of the polarization characteristics of the received orthogonally linearly polarized signals on a surface path with a length of 8 km is confirmed.

The intense magnetic field surrounding the electronic system in the ITER Tokamak necessitates the use of magnetic field shielding to protect electronic devices from failure. To ensure that the components installed in these areas can withstand ITER’s magnetic environment, they must be tested beforehand for magnetic field tolerance. This paper presents a magnetic shielding design for the Radial X-ray Camera (RXC) electronic system in ITER, silicon steel sheet is used as shielding material. The design scheme was simulated and analyzed using Ansys Maxwell software, and the shield shell was designed and optimized to reduce the magnetic induction intensity from 120 mT to less than 60 mT. To determine whether the magnetic field tolerance capability of the shield and electronic system meets ITER’s requirements, tests were conducted. Based on the experimental results, it has been observed that the shield is effective in shielding the magnetic field to 50–60 mT. Furthermore, the electronic system has been tested under a magnetic field intensity of 140 mT and 180 mT, and it has been found to be functioning normally, thereby meeting the requirements of ITER.

When ultracold neutrons interact with moving surfaces, their energy can change (so-called turbine effect). In this case, both an increase and a decrease in the neutron energy are possible. In previous experiments with the capture of ultracold neutrons in a gravitational trap by rotating it, it was made to have the shape of a body of revolution, which was done specifically to avoid the turbine effect. In this paper, the authors consider an experiment with a rotating gravitational trap that does not have the shape of a body of revolution. The Monte Carlo method was used to simulate the turbine effect at different stages of the experiment. The transformation of the neutron spectrum over time is calculated as a function of the trap rotation speed. A possible systematic error in the measurement of the neutron lifetime due to the influence of the turbine effect is considered. Experimental parameters are obtained for which it is absent.

A high-temperature (up to 1600°C) installation for measuring the coefficient of linear expansion (CLE) using a relative method is described. The measuring unit is installed in a protective glove box, which allowed measurements to be performed on samples irradiated in a reactor. Changes in the length of the sample during heating were recorded with a clock-type indicator head with an accuracy of 1 μm with the measurement range of 0–10 mm. The installation was used to determine the values of swelling of irradiated samples during high-temperature annealing and to obtain the values of the CLE of promising reactor materials. The average relative measurement error is 8–11%.

The article presents the results of the development of an energy sensor designed to control the energy of an electron beam released into the atmosphere from accelerators for applied purposes. The principle of operation of the device is based on the use of Vavilov–Cherenkov radiation, which occurs when an electron beam passes through a gas.

The purpose of the article is to show the advantages of a new design of a high-voltage rectangular pulse generator. Known analogues combine modules: signal generator; high-voltage key of N identical transistors (Q_k, k = 1….N) connected in series; gate driver of leading Q_k; high-voltage power source, its electromotive force, emf (E), feeds all Q_k and load (R) of the key. In analogs, divider resistors (r_k) and snubbers balance equality of voltages U_k on all Q_k. Under nonideal balance conditions E ≈ 0.7NU_max, where U_max is the maximum operating voltage of Q_k. The new solution differs in that the high-voltage power source sets not one but N emf E_k (E_i/E_j = const (i, j); i ≠ j; i, j = 1, 2, …, N) and each E_k feeds its Q_k through the load R_k. Experiments and simulations have revealed advantages of the new design: (1) the simplicity of the circuit and key tuning, (2) the fast transition ON→OFF for all Q_k (as R_k is small, R_k ( ll ) r_k), (3) the high pulse repetition rate, and (4) the greatly improved balancing of U_k voltages allows the E_k emf to be set so that ΣU_k ≈ ΣU_{k, max} at U_i, max ≠ U_k, max. The generator with the key based on two different MOSFETs (IXTL2N450 and IXTT1N450HV, U_max = 4500 V) and with a source where the E₂ = 2E₁ were used to excite vacuum ion emission from liquid Ga-based alloys.

The possibility of using synthetic diamond crystals as a sensitive element of resistive-type thermal sensors developed to control target heating in a neutron generator is discussed. Information about the design and manufacturing technology of a mock-up sample of the temperature sensor, as well as data from an experimental study of its dynamic characteristics, are given. On the example of a neutron generator developed based on a high-current accelerating diode, a scheme for thermal control of a neutron-forming target is proposed.