Pub Date : 2024-07-04DOI: 10.3103/s0027134924700206
I. A. Kolmychek, V. B. Novikov, A. I. Maydykovskiy, T. B. Murzina
Abstract
The interaction of laser radiation with magnetic media is a rapidly developing field of research, offering broad possibilities both for observing new effects and for studying and characterizing magnetic materials at micro- and macrolevels. This is especially important in connection with the development of modern technologies, which allow the creation of structures with fundamentally new magnetic and optical properties, whose realization is impossible in natural materials. The review presents the results of research on nonlinear optical effects in ferromagnetic nano- and microstructures, as well as films of different compositions. The unique possibilities of nonlinear optical diagnostics of anisotropic, vortex, and exchange-biased magnetic structures, visualization of the micromagnetic structure of surface layers of iron–garnets are demonstrated. The exceptional effectiveness of these approaches is based both on the high sensitivity of the method of optical second harmonic generations to the magnetic state of nanostructures and interfaces, and on the properties of symmetry of tensors of high-order magnetization-induced susceptibility.
{"title":"Second Harmonic Generation in Structures with Inhomogeneous Magnetization Distribution","authors":"I. A. Kolmychek, V. B. Novikov, A. I. Maydykovskiy, T. B. Murzina","doi":"10.3103/s0027134924700206","DOIUrl":"https://doi.org/10.3103/s0027134924700206","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The interaction of laser radiation with magnetic media is a rapidly developing field of research, offering broad possibilities both for observing new effects and for studying and characterizing magnetic materials at micro- and macrolevels. This is especially important in connection with the development of modern technologies, which allow the creation of structures with fundamentally new magnetic and optical properties, whose realization is impossible in natural materials. The review presents the results of research on nonlinear optical effects in ferromagnetic nano- and microstructures, as well as films of different compositions. The unique possibilities of nonlinear optical diagnostics of anisotropic, vortex, and exchange-biased magnetic structures, visualization of the micromagnetic structure of surface layers of iron–garnets are demonstrated. The exceptional effectiveness of these approaches is based both on the high sensitivity of the method of optical second harmonic generations to the magnetic state of nanostructures and interfaces, and on the properties of symmetry of tensors of high-order magnetization-induced susceptibility.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-04DOI: 10.3103/s0027134924700310
P. V. Jolos, E. A. Kolganova
Abstract
General information on the structure and properties of the first excited (1^{-}) states of even–even nuclei is provided. The poorly studied characteristics of (1^{-}) states, which are of interest for research within the framework of the experimental program at the Compton source of monochromatic gamma quanta of NCPhM (INOK), are discussed.
{"title":"Investigation of $$mathbf{1}^{mathbf{-}}_{mathbf{1}}$$ Excited States of Even–Even Nuclei","authors":"P. V. Jolos, E. A. Kolganova","doi":"10.3103/s0027134924700310","DOIUrl":"https://doi.org/10.3103/s0027134924700310","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>General information on the structure and properties of the first excited <span>(1^{-})</span> states of even–even nuclei is provided. The poorly studied characteristics of <span>(1^{-})</span> states, which are of interest for research within the framework of the experimental program at the Compton source of monochromatic gamma quanta of NCPhM (INOK), are discussed.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-04DOI: 10.3103/s0027134924700371
Mohsen Kheradmand Saadi, S. Di Pasquale, V. Giusti
Abstract
Recently, the OECD/NEA organization developed a benchmark problem based on a specific experiment conducted during the Rostov-2 first start-up procedure. The first phase of this benchmark gives an option to participants to develop their own two-group, assembly-wise homogenized cross sections. The main objective of this research is description of different techniques and methods employed during our own PMAXS libraries generation as well as their verification. The sophisticated SERPENT-2 Monte Carlo code has been employed for neutron transport in five distinct types of fuel assemblies and their corresponding group constants generation in a burnup and branch hierarchical structure. For each assembly 7 burnup states, 3 fuel temperature points, 2 moderator temperature points, 2 boron concentrations and 2 control rod states have been considered. The output files have been converted to PMAXS format using GENPMAXS interface. The verification of generated libraries has been conducted with two independent approaches. The first one is based on the comparison in assembly multiplication factor resulted from SERPENT and GENPMAXS codes. The results showed that the maximum reactivity difference between two codes is only 29 pcm. In second approach, the generated libraries have been fed to the PARCS code and neutronics results compared with reference data. The results showed that at different burnup states, the radial relative power and burnup distributions resulted from PARCS calculations are in good agreement with corresponding reference values. The maximum relative difference was less than 4(%) and the location of ‘‘hot assembly’’ was same.
{"title":"PMAXS Library Generation for the Benchmark on Rostov-2 VVER-1000 Reactor","authors":"Mohsen Kheradmand Saadi, S. Di Pasquale, V. Giusti","doi":"10.3103/s0027134924700371","DOIUrl":"https://doi.org/10.3103/s0027134924700371","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Recently, the OECD/NEA organization developed a benchmark problem based on a specific experiment conducted during the Rostov-2 first start-up procedure. The first phase of this benchmark gives an option to participants to develop their own two-group, assembly-wise homogenized cross sections. The main objective of this research is description of different techniques and methods employed during our own PMAXS libraries generation as well as their verification. The sophisticated SERPENT-2 Monte Carlo code has been employed for neutron transport in five distinct types of fuel assemblies and their corresponding group constants generation in a burnup and branch hierarchical structure. For each assembly 7 burnup states, 3 fuel temperature points, 2 moderator temperature points, 2 boron concentrations and 2 control rod states have been considered. The output files have been converted to PMAXS format using GENPMAXS interface. The verification of generated libraries has been conducted with two independent approaches. The first one is based on the comparison in assembly multiplication factor resulted from SERPENT and GENPMAXS codes. The results showed that the maximum reactivity difference between two codes is only 29 pcm. In second approach, the generated libraries have been fed to the PARCS code and neutronics results compared with reference data. The results showed that at different burnup states, the radial relative power and burnup distributions resulted from PARCS calculations are in good agreement with corresponding reference values. The maximum relative difference was less than 4<span>(%)</span> and the location of ‘‘hot assembly’’ was same.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-04DOI: 10.3103/s0027134924700309
A. S. Busarov, P. Yu. Glagolev, N. L. Popov
Abstract
One of the tasks of modern optical methods is the most complete description of the objects under study and the wave fields. For example, properties of the materials under study should be characterized not only by absorption but also by refraction, and the wave fields behind the object and near the detector should be characterized not only by intensity but also by phase. The work of Gerchberg and Saxton in 1972 was the first attempt to accomplish this task without using any optical elements, relying only on a quadratic detector and a computer simulation of the propagation of electromagnetic waves. Today, similar lensless imaging methods are applied across a wide range of wavelengths—from terahertz to hard X-ray. The purpose of this paper is to provide a brief introduction to the theory of lensless methods as applied to the X-ray wavelength range. It also presents the results of recent experiments on lensless imaging of test objects conducted at the Lebedev Physical Institute using lasers.
摘要 现代光学方法的任务之一是对研究对象和波场进行最完整的描述。例如，被研究材料的特性不仅要通过吸收来描述，还要通过折射来描述；物体后面和探测器附近的波场不仅要通过强度来描述，还要通过相位来描述。格奇伯格和萨克斯顿在 1972 年的研究中首次尝试在不使用任何光学元件的情况下，仅依靠一个二次探测器和对电磁波传播的计算机模拟来完成这一任务。如今，类似的无透镜成像方法已广泛应用于从太赫兹到硬 X 射线的各种波长。本文旨在简要介绍应用于 X 射线波长范围的无透镜方法理论。本文还介绍了列别杰夫物理研究所最近使用激光对测试对象进行无透镜成像的实验结果。
{"title":"X-Ray Lensless Optics and Ptychography","authors":"A. S. Busarov, P. Yu. Glagolev, N. L. Popov","doi":"10.3103/s0027134924700309","DOIUrl":"https://doi.org/10.3103/s0027134924700309","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>One of the tasks of modern optical methods is the most complete description of the objects under study and the wave fields. For example, properties of the materials under study should be characterized not only by absorption but also by refraction, and the wave fields behind the object and near the detector should be characterized not only by intensity but also by phase. The work of Gerchberg and Saxton in 1972 was the first attempt to accomplish this task without using any optical elements, relying only on a quadratic detector and a computer simulation of the propagation of electromagnetic waves. Today, similar lensless imaging methods are applied across a wide range of wavelengths—from terahertz to hard X-ray. The purpose of this paper is to provide a brief introduction to the theory of lensless methods as applied to the X-ray wavelength range. It also presents the results of recent experiments on lensless imaging of test objects conducted at the Lebedev Physical Institute using lasers.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-04DOI: 10.3103/s0027134924700279
A. A. Bykov
Abstract
We consider the problem of evolution of the internal transition layer for two-dimensional quasilinear initial-boundary value problem for the reaction-advection-diffusion equation in an inhomogeneous medium with a small parameter for higher derivatives. It is shown that in the zero (principal) order of the asymptotic series, the position of the internal transition layer is described by the Hamilton–Jacobi equation. The potential is calculated as an integral of the source density function within the limits of the equilibrium levels. The front line of the transition layer evolves in the same way as the constant-eikonal line (or wavefront line) for the problem of wave propagation in an inhomogeneous medium in short-wave (geometro-optical) asymptotics. The sum of the zero-and first-order asymptotic series is found. The destruction time of the contrast structure is evaluated.
{"title":"Evolution of a Two-Dimensional Moving Contrast Structure in an Inhomogeneous Medium with Advection","authors":"A. A. Bykov","doi":"10.3103/s0027134924700279","DOIUrl":"https://doi.org/10.3103/s0027134924700279","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>We consider the problem of evolution of the internal transition layer for two-dimensional quasilinear initial-boundary value problem for the reaction-advection-diffusion equation in an inhomogeneous medium with a small parameter for higher derivatives. It is shown that in the zero (principal) order of the asymptotic series, the position of the internal transition layer is described by the Hamilton–Jacobi equation. The potential is calculated as an integral of the source density function within the limits of the equilibrium levels. The front line of the transition layer evolves in the same way as the constant-eikonal line (or wavefront line) for the problem of wave propagation in an inhomogeneous medium in short-wave (geometro-optical) asymptotics. The sum of the zero-and first-order asymptotic series is found. The destruction time of the contrast structure is evaluated.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.3103/s0027134924700012
N. G. Chechenin, N. V. Novikov, A. A. Shirokova
Abstract
An analysis of the impact of high-energy cosmic radiation protons on the onboard electronics of the spacecraft was performed. It has been shown that protons can cause nuclear reactions with the atomic nuclei of electronics material. Residual nuclei formed as a result of a nuclear reaction have sufficiently high energy to cross the sensitive areas of several bits of electronics, and the high ionizing ability of nuclear fragments makes it possible to generate an excess charge of carriers that exceeds the critical charge for upsets to occur simultaneously in several bits of an electronic device.
{"title":"Multibit Upsets of Onboard Spacecraft Electronics from a Single Cosmic Radiation Particle","authors":"N. G. Chechenin, N. V. Novikov, A. A. Shirokova","doi":"10.3103/s0027134924700012","DOIUrl":"https://doi.org/10.3103/s0027134924700012","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>An analysis of the impact of high-energy cosmic radiation protons on the onboard electronics of the spacecraft was performed. It has been shown that protons can cause nuclear reactions with the atomic nuclei of electronics material. Residual nuclei formed as a result of a nuclear reaction have sufficiently high energy to cross the sensitive areas of several bits of electronics, and the high ionizing ability of nuclear fragments makes it possible to generate an excess charge of carriers that exceeds the critical charge for upsets to occur simultaneously in several bits of an electronic device.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140597806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.3103/s0027134924700024
M. P. Zarubin, A. F. Nizamieva, S. I. Alexeev, S. V. Mitrofanov, Y. E. Gorshkova, E. V. Kravchenko
Abstract
The unique protein Dsup of the tardigrade Ramazzottius varieornatus increases resistance to radiation and oxidative stress in various organisms and in human cell culture. According to simulation data, Dsup forms a complex with DNA with an intermolecular distance of ({sim}4) Å, as a result of which DNA is less damaged by reactive oxygen species generated during radiation exposure. However, the stability of the Dsup protein itself under the effect of ionizing radiation remains unclear, which is important for assessing its radioprotective potential and understanding the molecular mechanisms of action of this protein under conditions of high doses of radiation. In this work, the radiation degradation of the Dsup protein after irradiation with (gamma)-quanta using small-angle X-ray scattering (SAXS) and electrophoresis of proteins in polyacrylamide gel under denaturing conditions (SDS-PAGE) was studied for the first time. It was shown that, unlike the control protein bovine serum albumin, the spatial-structural characteristics of the Dsup protein remain almost unchanged even when exposed high doses of radiation (5 and 10 kGy), which indicates its high radiation stability.
{"title":"Radioprotective Protein of Tardigrades Dsup (Damage Suppressor) is Resistant to High Doses of Ionizing Radiation","authors":"M. P. Zarubin, A. F. Nizamieva, S. I. Alexeev, S. V. Mitrofanov, Y. E. Gorshkova, E. V. Kravchenko","doi":"10.3103/s0027134924700024","DOIUrl":"https://doi.org/10.3103/s0027134924700024","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The unique protein Dsup of the tardigrade <i>Ramazzottius varieornatus</i> increases resistance to radiation and oxidative stress in various organisms and in human cell culture. According to simulation data, Dsup forms a complex with DNA with an intermolecular distance of <span>({sim}4)</span> Å, as a result of which DNA is less damaged by reactive oxygen species generated during radiation exposure. However, the stability of the Dsup protein itself under the effect of ionizing radiation remains unclear, which is important for assessing its radioprotective potential and understanding the molecular mechanisms of action of this protein under conditions of high doses of radiation. In this work, the radiation degradation of the Dsup protein after irradiation with <span>(gamma)</span>-quanta using small-angle X-ray scattering (SAXS) and electrophoresis of proteins in polyacrylamide gel under denaturing conditions (SDS-PAGE) was studied for the first time. It was shown that, unlike the control protein bovine serum albumin, the spatial-structural characteristics of the Dsup protein remain almost unchanged even when exposed high doses of radiation (5 and 10 kGy), which indicates its high radiation stability.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140597782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.3103/s0027134924700164
E. Yu. Zarubina, M. A. Rogozhina, I. A. Chugrov
Abstract
An indirect-drive cryogenic target is necessary for research in the field of laser thermonuclear fusion at a megajoule energy level facility. Solid fuel layer in the target must meet high requirements: a roughness of the inner cryolayer surface must be less than 1 (mu)m, deviations from the sphericity and the concentricity must be less than 1(%). This paper describes the results of the research on meeting these requirements, notably, cryolayer formation and its characterization. Due to the slow crystallization method of the deuterium layer with its simultaneous heating by IR radiation, it is possible to obtain deviations from the sphericity and the concentricity of the inner cryolayer surface within limits of 2(%), the roughness, within limits of 20 (mu)m. Theoretical thermal calculations of the target construction are compared with experiment. The program system was developed using the optical shadow method which makes it possible to measure liquid fuel when filling the shell during the performance of the experiment, to perform the characterization of the solid cryogenic layer parameters, and to evaluate characterization results robustness.
{"title":"Creation of the Indirect-Drive Cryogenic Target with the Solid Deuterium Layer","authors":"E. Yu. Zarubina, M. A. Rogozhina, I. A. Chugrov","doi":"10.3103/s0027134924700164","DOIUrl":"https://doi.org/10.3103/s0027134924700164","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>An indirect-drive cryogenic target is necessary for research in the field of laser thermonuclear fusion at a megajoule energy level facility. Solid fuel layer in the target must meet high requirements: a roughness of the inner cryolayer surface must be less than 1 <span>(mu)</span>m, deviations from the sphericity and the concentricity must be less than 1<span>(%)</span>. This paper describes the results of the research on meeting these requirements, notably, cryolayer formation and its characterization. Due to the slow crystallization method of the deuterium layer with its simultaneous heating by IR radiation, it is possible to obtain deviations from the sphericity and the concentricity of the inner cryolayer surface within limits of 2<span>(%)</span>, the roughness, within limits of 20 <span>(mu)</span>m. Theoretical thermal calculations of the target construction are compared with experiment. The program system was developed using the optical shadow method which makes it possible to measure liquid fuel when filling the shell during the performance of the experiment, to perform the characterization of the solid cryogenic layer parameters, and to evaluate characterization results robustness.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140597805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.3103/s0027134924700140
S. S. Belyshev, V. V. Varlamov, L. Z. Dzhilavyan, A. A. Kuznetsov, A. M. Lapik, A. L. Polonski, A. V. Rusakov, V. I. Shvedunov
Abstract
Proposed as initial activation experiments for photonuclear research with (gamma)-quanta at energies (E_{gamma}leq 40) MeV are those using a source of backward Compton scattered laser radiation on accelerated electrons, which is currently under development. These experiments are crucial both for refining the techniques of tuning and monitoring such (gamma)-beams, and for investigating the excitation of pygmy and giant resonances in nuclei at (E_{gamma}) near the threshold of the ((gamma,n)) reactions, as well as the multiplicity of photoneutrons during the de-excitation of E1 giant resonances at (E_{gamma}) above the threshold of the ((gamma,2n)) reactions.
{"title":"On Activation Studies of Photonuclear Reactions on $${gamma}$$ -Beams from Backward Compton Scattering at $$boldsymbol{E}_{{gamma}}boldsymbol{leq 40}$$ MeV","authors":"S. S. Belyshev, V. V. Varlamov, L. Z. Dzhilavyan, A. A. Kuznetsov, A. M. Lapik, A. L. Polonski, A. V. Rusakov, V. I. Shvedunov","doi":"10.3103/s0027134924700140","DOIUrl":"https://doi.org/10.3103/s0027134924700140","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Proposed as initial activation experiments for photonuclear research with <span>(gamma)</span>-quanta at energies <span>(E_{gamma}leq 40)</span> MeV are those using a source of backward Compton scattered laser radiation on accelerated electrons, which is currently under development. These experiments are crucial both for refining the techniques of tuning and monitoring such <span>(gamma)</span>-beams, and for investigating the excitation of pygmy and giant resonances in nuclei at <span>(E_{gamma})</span> near the threshold of the (<span>(gamma,n)</span>) reactions, as well as the multiplicity of photoneutrons during the de-excitation of E1 giant resonances at <span>(E_{gamma})</span> above the threshold of the (<span>(gamma,2n)</span>) reactions.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140597690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.3103/s0027134924700097
S. G. Zheltoukhov, A. M. Tatarnikov, A. A. Belyakova, E. A. Koksharova
Abstract
This paper presents a prototype of an infrared photometer, created at the Sternberg Astronomical Institute, Lomonosov Moscow State University (SAI MSU), based on the commercial infrared module Gavin-615A. The operating spectral range of the photometer is 3–5 (mu)m. Investigations of the photometer’s detector have shown that its parameters coincide with those stated by the manufacturer. The nonlinearity of the detector does not exceed ({sim}5%) across the entire signal range, and coefficients for correction functions were determined. Additionally, we determined the readout noise (textrm{RN}=1200pm 210e^{-}), the conversion coefficient (textrm{GAIN}=520pm 9e^{-}/)ADU, the signal magnitude of the bias frame (textrm{BIAS}=960.5pm 2.2) ADU, and the dark current ({approx}(9.3pm 1.1)times 10^{6}e^{-})/s, which is the sum of the detector’s dark current and the radiation from the entrance window of the detector module. The value of dark current was measured at a window temperature of (6^{circ})C. Observations commenced with the photometer at the 2.5-m telescope of the Caucasian Mountain Observatory of MSU, with the first results presented in this paper. The unvignetted field of view was (30^{primeprime}). In the (M) band under good atmospheric conditions, an image quality close to the diffraction limit was achieved. Images of a star with brightness (L=7.96) and (M=6.78) were obtained over the 20-s exposure time and a (textrm{SNR}sim 10) ratio. It is shown that at high image quality with (textrm{SNR}=3) and exposure of 20 s it is possible to observe stars up to (Lsim) 9({}^{m}) and (Msim 8^{m}). The main module of the photometer was also used in measurements of the sky background brightness.
{"title":"New Infrared Camera of the Caucasian Mountain Observatory of the SAI MSU: Design, Main Parameters, and First Light","authors":"S. G. Zheltoukhov, A. M. Tatarnikov, A. A. Belyakova, E. A. Koksharova","doi":"10.3103/s0027134924700097","DOIUrl":"https://doi.org/10.3103/s0027134924700097","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>This paper presents a prototype of an infrared photometer, created at the Sternberg Astronomical Institute, Lomonosov Moscow State University (SAI MSU), based on the commercial infrared module Gavin-615A. The operating spectral range of the photometer is 3–5 <span>(mu)</span>m. Investigations of the photometer’s detector have shown that its parameters coincide with those stated by the manufacturer. The nonlinearity of the detector does not exceed <span>({sim}5%)</span> across the entire signal range, and coefficients for correction functions were determined. Additionally, we determined the readout noise <span>(textrm{RN}=1200pm 210e^{-})</span>, the conversion coefficient <span>(textrm{GAIN}=520pm 9e^{-}/)</span>ADU, the signal magnitude of the bias frame <span>(textrm{BIAS}=960.5pm 2.2)</span> ADU, and the dark current <span>({approx}(9.3pm 1.1)times 10^{6}e^{-})</span>/s, which is the sum of the detector’s dark current and the radiation from the entrance window of the detector module. The value of dark current was measured at a window temperature of <span>(6^{circ})</span>C. Observations commenced with the photometer at the 2.5-m telescope of the Caucasian Mountain Observatory of MSU, with the first results presented in this paper. The unvignetted field of view was <span>(30^{primeprime})</span>. In the <span>(M)</span> band under good atmospheric conditions, an image quality close to the diffraction limit was achieved. Images of a star with brightness <span>(L=7.96)</span> and <span>(M=6.78)</span> were obtained over the 20-s exposure time and a <span>(textrm{SNR}sim 10)</span> ratio. It is shown that at high image quality with <span>(textrm{SNR}=3)</span> and exposure of 20 s it is possible to observe stars up to <span>(Lsim)</span> 9<span>({}^{m})</span> and <span>(Msim 8^{m})</span>. The main module of the photometer was also used in measurements of the sky background brightness.</p>","PeriodicalId":711,"journal":{"name":"Moscow University Physics Bulletin","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140597784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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