Optimization of light collection from crystal scintillators for cryogenic experiments

High light collection efficiency is an important requirement in any application of scintillation detectors. The purpose of this study is to investigate the possibility for improving this parameter in cryogenic scintillation bolometers, which can be considered as a promising detectors in experiments investigating neutrinoless double beta decay and dark matter. Energy resolutions and relative pulse amplitudes of scintillation detectors using ZnWO4 scintillation crystals of different shapes (cylinder 20 mm in dimater by 20 mm and hexagonal prism with diagonal 20 mm and height 20 mm), reflector materials and shapes, optical contact and surface properties (polished and diffused) were measured at room temperature. Propagation of optical photons in these experimental conditions was simulated using Geant4 and ZEMAX codes. The results of the simulations are found to be in good agreement with each other and with direct measurements of the crystals. This could be applied to optimize the geometry of scintillation detectors used in the cryogenic experiments.Comment: 12 pages, 8 figures, 1 Tabl

Impact of geometry on light collection efficiency of scintillation detectors for cryogenic rare event searches

Simulations of photon propagation in scintillation detectors were performed with the aim to find the optimal scintillator geometry, surface treatment, and shape of external reflector in order to achieve maximum light collection efficiency for detector configurations that avoid direct optical coupling, a situation that is commonly found in cryogenic scintillating bolometers in experimental searches for double beta decay and dark matter. To evaluate the light collection efficiency of various geometrical configurations we used the ZEMAX ray-tracing software. It was found that scintillators in the shape of a triangular prism with an external mirror shaped as truncated cone gives the highest light collection efficiency. The results of the simulations were confirmed by carrying out measurements of the light collection efficiencies of CaWO4 crystal scintillators. A comparison of simulated and measured values of light output shows good agreemen

Microscopic features of buccal epithelium in smokers students indo-dravidian race: by E. Hooton

We have studied the microscopic features of buccal epithelium in smoking students of Indo-Dravidian race. In the epithelial cells of the mucous cheek surface of smoking students we revealed the scored nuclei with tongue- and broken egg-type protrusions, micronuclei, cellular dimorphism, binuclear cells, as well as a significant decrease in nuclear-cytoplasmic ratio, as compared to the control, which may indicate the presence of local inflammation resulting from the toxic effects of smoking products on the oral mucos

4f-5d transitions of Pr3+ in elpasolite lattices

The 4f5d→4f2 emission spectra of Cs2MPrCl6 (M = Na,Li) and CS2NaYCl6:Pr3+ have been recorded at temperatures down to 10 K. The spectra of Pr3+ in the cubic host Cs2NaYCl6 are the most clearly resolved, and 15 transitions to terminal crystal field levels of symmetry representations Γ5g and Γ4g have been observed and assigned, thereby inferring that the symmetry representation of the lowest 4f5d crystal field level is Γ3u. Each transition is characterized by strong progressions in two totally symmetric vibrational modes. The relative displacement of the potential energy curves for the 4f2 and 4f5d crystal field levels, along the α1g internal mode coordinate, is small, being only about 5 pm. The 10-K ultraviolet absorption spectra of CS2NaYCl6:Pr3+ are assigned to transitions from the [3H4] Γ1g electronic ground state to terminal Γ4u crystal field levels of 4f5d. Nontotally symmetric gerade vibrational modes only provide minor intensity contributions. The large energy gap between the d-f emission and f-d absorption spectra of Pr3+ in the cubic elpasolite host is rationalized. The 8-K excitation spectra of Cs2NaPrCl6 and Cs2NaYCl6:Pr3+, excited by synchrotron radiation, show that the transitions to 4f5d fall into two groups. The energy levels and wave vectors of the (independent) 4f2 and 4f5d configurations of Pr3+ have been calculated using a model which includes spin-orbit coupling and crystal field and Coulomb interactions, as well as the configuration interaction of 4f2 with 4f6p. Using the eigenvector of the predominantly high-spin, lowest excited crystal field level of 4f5d, the emission intensities are reasonably well simulated. However, the refinement of the 4f2→4f5d absorption intensities requires a more detailed knowledge of the crystal field energy level scheme of 4f5d. The configuration interaction of 4f5d with 4f6s and 4f5g is discussed.published_or_final_versio

THE ROLE OF THE DIGITAL ECONOMY IN THE DEVELOPMENT OF THE LABOR MARKET IN BELARUS

The concept of digital economy and main aspects of digitalization are revealed in the article. The state of belarusian labor market by means of digital sector development is considered.В статье раскрываются понятие цифровой экономики и основные аспекты дигитализации. Рассмотрено состояние рынка труда Беларуси посредством развития цифрового сектора

Estimation of the Immunity of a Satellite Communication System Based on Wideband Signals in Relation to Impulse and Fluctuating Interferences

Поступила: 14.04.2023. Принята в печать: 25.04.2023.Received: 14.04.2023. Accepted: 25.04.2023.В статье разработана модель системы спутниковой связи на основе широкополосных сигналов с относительным фазовым кодированием. Используется система из четырех сигналов с двоичной фазовой манипуляцией. Спектры сигналов расширены методом прямой последовательности. Моделируется работы системы в условиях действия импульсных радиопомех и в условиях действия флуктуационных помех. Получены характеристики помехоустойчивости системы к импульсным помехам с распределением Джонсона и помехам в виде белого гауссовского шума.A model of a satellite communication system based on wideband signals with relative diphase encoding is developed in the paper. A system of four signals with binary phase shift keying is used. Spectra of the signals are spread by the direct sequence technique. The developed system operation under conditions of impulse electromagnetic interference and under the influence of fluctuation interference is simulated. The dependences of bit error rate on signal-to-interference ratio are evaluated in the cases of impulse interference with Johnson distribution and white Gaussian noise affecting the signal

Detection of the Natural Alpha Decay of Tungsten

The natural alpha decay of 180W has been unambiguously detected for the first time. The alpha peak is found in a (gamma,beta and neutron)-free background spectrum. This has been achieved by the simultaneous measurement of phonon and light signals with the CRESST cryogenic detectors. A half-life of T1/2 = (1.8 +- 0.2) x 10^18 y and an energy release of Q = (2516.4 +- 1.1 (stat.) +- 1.2 (sys.)) keV have been measured. New limits are also set on the half-lives of the other naturally occurring tungsten isotopes.Comment: Submitted to Physical Review C Revised versio