Instruments and Experimental Techniques最新文献

The new generation neutrino telescope Baikal-GVD is under deployment in Lake Baikal. The telescope registers Cherenkov radiation resulting from the interaction of neutrinos with the water environment of the lake, using the spatial structure of optical modules – photodetectors. To determine the direction to the neutrino source, it is necessary to know the coordinates of each module at the time the event was recorded. The article describes the design and operating principle of the inertial positioning system, which serves to determine the spatial position of modules in the aquatic environment, and presents the first results of its operation.

A scheme of a charge-sensitive preamplifier (CSP) for measuring the energy and time of flight of detected particles is described. The CSP has two outputs. At the E-output, the signal is determined by the integral of the charge formed by a particle in a semiconductor detector. The signal amplitude at this output is proportional to the particle energy. At the T-output, the signal follows the shape of the detector current pulse and has a short rise time, which reduces the timing error. A circuit diagram of the CSP is shown, and calculations of the signal parameters at the E and T outputs are given. The results of modeling and the measured parameters of the proposed scheme are presented. The criterion of the expediency of using the time channel of the CSP depending on the radiation time of the radiator crystal or the charge collection time is obtained. The CSP is intended for use in photon spectrometers based on PWO crystals and avalanche photodiodes, but it can also be used in spectrometers with other types of semiconductor detectors.

A large array of experimental data on the extraction of large cross-section electron beams into the atmosphere using low-energy (80–300 keV) electron accelerators has been analyzed. The electron accelerators considered are based on various emission types: thermionic emission, explosive electron emission, different plasma-cathode discharges, and a high-voltage glow discharge. The “large area effect” has been retrospectively demonstrated and quantified, which consists in reducing the maximum current density of an electron beam extracted into the atmosphere with an increase in the cross-sectional area of the beam, but while maintaining stable generation conditions. Based on the data analysis, it is shown that there is a technological constraint on the average power density of large cross-section electron beams generated by low-energy electron accelerators, which is as high as 40 W/cm². This constraint is associated with the resistance of thin foils for extracting electron beams from vacuum into the atmosphere.

The Multi-Purpose Detector (MPD) is being created at the NICA collider (JINR, Dubna) to study the properties of the hot and dense nuclear matter in the interaction point of colliding heavy-ion beams. The electromagnetic calorimeter in the new experimental setup is responsible for identifying γ-quanta and electrons (positrons), measuring their energy and coordinates, and separating them from hadrons. For the stable operation of the 38 400 channels of the calorimeter, an LED monitoring system with fiber-optic light distribution was developed and studied

The article is devoted to methods of studying thermal conductivity and, in particular, to the pulse heating method. The classification of methods for studying thermal conductivity and their advantages and disadvantages are described. The article provides generalized information about the probes used in experimental setups of the pulse heating method as well as a description of the probe used in the implemented setup. Experimental thermograms with an analysis of the factors influencing the result, as well as options for assessing their contribution to the overall measurement result, are presented. The results of testing the installation and comparison of the obtained values of thermal conductivity coefficients with standard values presented in the literature are presented.

One of the possible modifications of a time-analyzing PIF-01 electron-image tube is described. It is shown how, without changing the dimensions of the device and the requirements for its electronics, it is possible to improve the time resolution of the converter. Mathematical modeling of the main technical parameters of the modified electron-image tube is performed, and the experimental results confirming the performed calculations are presented.

Screen printing stands out due to its ease of setup and versatile printing capabilities, supporting various substrates such as glass, ceramics, textiles, plastics, and metals. This technique offers precise control over critical deposition parameters, including nanoink thickness, ink viscosity, and packing density, which are essential for high-quality prints. In this study, ZnO nanoparticles dispersed in ethylene glycol were processed to achieve a moderate viscosity of 23.8 cP. This laboratory-scale setup was designed to optimize screen printing parameters for enhanced ZnO deposition quality. Key variables, such as the viscosity of ZnO nanoink, printing modes, and stroke techniques, were rigorously assessed for their impact on print consistency, with adjustments made to refine the process. During experimentation, challenges emerged, including ink blurring, uncontrolled distribution, leakage, uneven prints, lack of sharpness, clogging, and misalignment. Specific adjustments, such as optimizing snap-off and off-contact distances, using screen mesh tape, applying controlled pressure, and securing the screen with clamps and vacuum holes, were implemented to address these challenges. This study introduces an optimized screen-printing setup for reliable ZnO nanoparticle deposition on glass substrate, supporting scalable production for applications in nanotechnology. Voltage measurements on the sensor made using the printed zinc oxide electrode yielded up to 0.9 mV which is suitable for low order flow measurements.

A waveguide–microstrip junction designed to connect a WR22 rectangular waveguide with a cross section of 3.759 × 1.889 mm² to a microstrip line on an aluminum oxide substrate with a thickness of 0.127 mm is presented. The results of electromagnetic modeling of the structure and measurement of the S‑parameters of the mockup, which includes two “back-to-back” connected junctions, are presented. In the operating frequency range with an overlap of 1 : 1.5, the values of direct and return losses of the measured mockup do not exceed –2.7 and –10 dB, respectively. The device can be used as an integrated structural element of various functional units of radio engineering systems.

In this work, a Piezoelectric Drive Amplifier (PDA) was designed and constructed for the first time to calibrate Ball Pen Probe (BPP) pins of Mix Probe in order to measure plasma potential in IR-T1 tokamak. The PDA amplifies a triangular wave generated by a signal generator with ±10 V and 1 kHz frequency to ±100 V, 1 kHz frequency and a maximum current 100 mA to sweep the collector of BPP of the mix probe. Current–voltage characteristic of BPP was plotted for a 10 ms plasma duration at Last Closed Flux Surface (LCFS) while the collector was swept between ±100 V by the PDA. The Ball Pen coefficient (({{{{alpha }}}_{{{text{BPP}}}}})) was also calculated to be approximately 0.5. The time trace of plasma potential and electron temperature was additionally derived from the floating potential, which was assessed using both the BPP and Langmuir pins. The floating potential measured by the BPP is much more closely aligned with the plasma potential than the floating potential measured by the LP. Consequently, we can regard the floating potential measured by the BPP as the plasma potential.

A fiber-optic temperature sensor with a sensitive element based on a silicon Fabry–Perot microinterferometer, the temperature of which is measured by the shift of interference fringes due to the dependence of the refractive index of silicon on temperature, is described. The Fabry–Perot interferometer is a silicon plate with dimensions 500 × 500 µm² and thickness 20 µm located at the end of a single-mode fiber. The conversion coefficient of such a Fabry-Perot interferometer is approximately 1 nW/°C, which, when using modern balanced photodetectors, provides the sensitivity of the order of 5 × 10^–3°C.