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Bulletin of the Lebedev Physics Institute最新文献

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A New Criterion for Determining Optical Damage of Nonlinear Optical Crystals, Based on the Use of an RF Oscillator Circuit 基于使用射频振荡器电路的非线性光学晶体光损伤新判据
IF 0.6 4区 物理与天体物理
Bulletin of the Lebedev Physics Institute Pub Date : 2024-04-18 DOI: 10.3103/S1068335624600165
K. V. Zotov, N. V. Tereshchenko, A. Yu. Ostapiv, G. Yu. Ivanov, O. A. Ryabushkin
{"title":"A New Criterion for Determining Optical Damage of Nonlinear Optical Crystals, Based on the Use of an RF Oscillator Circuit","authors":"K. V. Zotov,&nbsp;N. V. Tereshchenko,&nbsp;A. Yu. Ostapiv,&nbsp;G. Yu. Ivanov,&nbsp;O. A. Ryabushkin","doi":"10.3103/S1068335624600165","DOIUrl":"10.3103/S1068335624600165","url":null,"abstract":"<p>A criterion is proposed for determining laser breakdown in nonlinear optical crystals, based on measuring the absorption coefficient of optical radiation. A possibility of using a Pierce oscillator is demonstrated to determine the optical absorption coefficient in real time. The proposed criterion is applied to find the optical damage threshold of a lithium niobate crystal, which is 500 mJ/cm<sup>2</sup>, taking into account the self-focusing effect.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140630280","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}
引用次数: 0
Optimization of the Reflective Surface Shape of a Variable Curvature Mirror 优化变曲率反射镜的反射面形状
IF 0.6 4区 物理与天体物理
Bulletin of the Lebedev Physics Institute Pub Date : 2024-04-18 DOI: 10.3103/S1068335624600189
A. S. Mokeev
{"title":"Optimization of the Reflective Surface Shape of a Variable Curvature Mirror","authors":"A. S. Mokeev","doi":"10.3103/S1068335624600189","DOIUrl":"10.3103/S1068335624600189","url":null,"abstract":"<p>We report a computational and theoretical study of the shape of a reflective surface of a variable curvature mirror (VCM) with a different thickness distribution along the mirror radius. An analytical expression is proposed for the thickness distribution and a deviation of the reflective VCM surface shape with such a distribution from the parabolic shape is assessed in comparison with the exponential and cycloid thickness profiles known in the literature. It is shown that the use of the proposed thickness distribution can significantly reduce spherical aberration and improve the quality of the shape of the reflective VCM surface in the focal length range from 50 to 500 m. It is assumed that this VCM design can be used in an optical system for laser cutting of metal structures.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140627949","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}
引用次数: 0
Fabrication and Study of Generation Characteristics of Monolithic Ceramic Microchip Nd3+:YAG/Cr4+:YAG Lasers 单片陶瓷微芯片 Nd3+:YAG/Cr4+:YAG 激光器的制作和发电特性研究
IF 0.6 4区 物理与天体物理
Bulletin of the Lebedev Physics Institute Pub Date : 2024-04-18 DOI: 10.3103/S1068335624600177
A. Yu. Kanaev, A. L. Koromyslov, K. V. Lopukhin, I. M. Tupitsyn, E. A. Cheshev
{"title":"Fabrication and Study of Generation Characteristics of Monolithic Ceramic Microchip Nd3+:YAG/Cr4+:YAG Lasers","authors":"A. Yu. Kanaev,&nbsp;A. L. Koromyslov,&nbsp;K. V. Lopukhin,&nbsp;I. M. Tupitsyn,&nbsp;E. A. Cheshev","doi":"10.3103/S1068335624600177","DOIUrl":"10.3103/S1068335624600177","url":null,"abstract":"<p>The characteristics of monolithic ceramic Nd<sup>3+</sup>:YAG/Cr<sup>4+</sup>:YAG chip lasers are investigated and their fabrication technology is presented. Only CaO/MgO (without SiO<sub>2</sub>) were used as sintering aids. The conversion of Cr<sup>3+</sup> ions to Cr<sup>4+</sup> ions was 2.19 to 2.43% in different specimens. The thickness of the transition region between Nd<sup>3+</sup>:YAG and Cr<sup>4+</sup>:YAG was up to 400 μm. Laser generation of pulses with an energy of up to 200 μJ and duration of up to 0.9 ns at a repetition rate of 7.5 kHz was produced.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140630544","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}
引用次数: 0
The Prototype of a Magnetic Field Compensator 磁场补偿器原型
IF 0.6 4区 物理与天体物理
Bulletin of the Lebedev Physics Institute Pub Date : 2024-04-04 DOI: 10.3103/S1068335623601541
V. I. Alekseev, V. A. Baskov, V. A. Dronov, L. A. Gorbov, A. I. L’vov, A. V. Koltsov, V. V. Polyansky, S. S. Sidorin, E. A. Khafizova
{"title":"The Prototype of a Magnetic Field Compensator","authors":"V. I. Alekseev,&nbsp;V. A. Baskov,&nbsp;V. A. Dronov,&nbsp;L. A. Gorbov,&nbsp;A. I. L’vov,&nbsp;A. V. Koltsov,&nbsp;V. V. Polyansky,&nbsp;S. S. Sidorin,&nbsp;E. A. Khafizova","doi":"10.3103/S1068335623601541","DOIUrl":"10.3103/S1068335623601541","url":null,"abstract":"<p>The paper describes the design of a prototype magnetic field compensator intended to eliminate the influence of the edge magnetic field of the S-25P Pakhra accelerator magnet, Lebedev Physical Institute, on the electron beam during its output. The results of the study showed that this design could reduce an external magnetic field of <i>B</i><sub>0</sub> ~ 0.1 T to zero values inside the prototype.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140572835","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}
引用次数: 0
Phase Portrait of a Beam of Charged Particles Reflected from a Material Medium 物质介质反射的带电粒子束的相位图
IF 0.6 4区 物理与天体物理
Bulletin of the Lebedev Physics Institute Pub Date : 2024-04-04 DOI: 10.3103/S1068335623600572
V. G. Kurakin
{"title":"Phase Portrait of a Beam of Charged Particles Reflected from a Material Medium","authors":"V. G. Kurakin","doi":"10.3103/S1068335623600572","DOIUrl":"10.3103/S1068335623600572","url":null,"abstract":"<p>We report derivation of a distribution function of charges scattered due to an oblique incidence of a needle-shaped beam of charged particles from a vacuum onto a material medium, with the scattered particles landing up on the plane separating the medium and vacuum. To this end, the distribution function is used for multiple Coulomb scattering of a beam propagating in a homogeneous and unbounded medium. The phase plane shows the distributions of scattered charges corresponding to certain fixed values of the distribution function, i.e., phase portraits of a beam.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140572829","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}
引用次数: 0
Sources of Primary Cosmic Rays at an Energy of ~100 PeV 能量约为 100 PeV 的初级宇宙射线源
IF 0.6 4区 物理与天体物理
Bulletin of the Lebedev Physics Institute Pub Date : 2024-04-04 DOI: 10.3103/S1068335623601024
S. E. Pyatovsky
{"title":"Sources of Primary Cosmic Rays at an Energy of ~100 PeV","authors":"S. E. Pyatovsky","doi":"10.3103/S1068335623601024","DOIUrl":"10.3103/S1068335623601024","url":null,"abstract":"<p>A comparative analysis of the spectra of primary cosmic rays (PCR) over <i>Е</i><sub>0</sub> and the spectra of variable stars over the periods is performed with for the purpose of determining the causes of irregularities in the PCR spectrum over <i>Е</i><sub>0</sub>. The dependence between periods of variable stars and the maximum energy <i>Е</i><sub>0</sub> of PCR nuclei generated by such star types is shown. The irregularities in the PCR spectrum by <i>Е</i><sub>0</sub> are associated with the transition of one dominant star type to another with increasing <i>Е</i><sub>0</sub>. The knee in the PCR spectrum at <i>Е</i><sub>0</sub> = 3–5 PeV is associated with a decrease in the contribution of SRB variability stars and the further increase in the contribution of stars of Myra-type variability to the PCR flux. The bump in the PCR spectrum with a maximum at <i>Е</i><sub>0</sub> = 80 PeV is formed by giant and supergiant stars of the Myra-type and SRC variabilities.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140572827","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}
引用次数: 0
Monte Carlo Simulation of Liver Dosimetry with Yttrium-90 Radionuclide Using Gate: 3D Phantom 使用门：三维模型对钇-90 放射性核素的肝脏剂量测定进行蒙特卡罗模拟
IF 0.6 4区 物理与天体物理
Bulletin of the Lebedev Physics Institute Pub Date : 2024-04-04 DOI: 10.3103/S1068335623600201
Ayşe Karadeniz-Yildirim, Suat Ozkorucuklu, Handan Tanyildizi-Kokkulunk, Mustafa Demir, Dogan Yasar
{"title":"Monte Carlo Simulation of Liver Dosimetry with Yttrium-90 Radionuclide Using Gate: 3D Phantom","authors":"Ayşe Karadeniz-Yildirim,&nbsp;Suat Ozkorucuklu,&nbsp;Handan Tanyildizi-Kokkulunk,&nbsp;Mustafa Demir,&nbsp;Dogan Yasar","doi":"10.3103/S1068335623600201","DOIUrl":"10.3103/S1068335623600201","url":null,"abstract":"<p>This study is aimed to validate <sup>90</sup>Y dosimetry with MC simulation by comparing the TLD measurements results obtained in 3D liqid phantom (LP) and its monte carlo (MC) simulation. In the first step, tumor imitation was filled with 1900 µCi (70.3 MBq) amount of <sup>99m</sup>Tc activity in LP. In addition, 24 thermoluminescence dosimetry chips (TLD-100) were placed in 8 different locations in the LP. The same measurement system was created in GEANT4 Tomography Emission Application (GATE version 8.1). DoseActor library was defined for 24 points instead of TLDs and doses were taken. In the second step, <sup>90</sup>Y with the amount of 2 mCi (74 MBq) activity and 27 DoseActor libraries were placed in tumor mimic and different locations in LP to calculate the dose distribution with GATE. GATE and TLD results for <sup>99m</sup>Tc were compared for validation. The strong correlation coefficient was calculated between the instant absorbed dose rates obtained via TLD measurements and GATE calculations as <i>R</i><sup>2</sup> = 0.994. At the <sup>90</sup>Y dosimetry, the highest, lowest and mean cumulative absorbed doses calculated by GATE for a half-life were found to be 1.166 × 10<sup>2</sup> ± 3.907 × 10<sup>–1</sup>, 5.440 × 10<sup>1</sup> ± 2.597 × 10<sup>–1</sup>, and 75.145 ± 0.303 Gy in the tumor imitation, and 1.167 × 10<sup>1</sup> ± 1.777 × 10<sup>−1</sup>, 9.929 × 10<sup>−5</sup> ± 6.905 × 10<sup>−5</sup>, 1.169 ± 0.019 Gy in the liver parenchymal tissue imitation, respectively. GATE program is considered to be a promising application in internal radionuclide dosimetry, based on linear correlation between TLD and GATE measurements in our study.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140591620","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}
引用次数: 0
Scintillation Lu2SiO5 ‒ z:Y3+:Ce3+:Ca2+ Crystal for Positron Emission Tomography 用于正电子发射断层扫描的闪烁 Lu2SiO5 - z:Y3+:Ce3+:Ca2+ 晶体
IF 0.6 4区 物理与天体物理
Bulletin of the Lebedev Physics Institute Pub Date : 2024-04-04 DOI: 10.3103/S1068335623601231
I. M. Ermochenkov, Yu. D. Zavartsev, A. I. Zagumennyi, O. V. Yurasova, I. V. Morozov, D. V. Serebryakov
{"title":"Scintillation Lu2SiO5 ‒ z:Y3+:Ce3+:Ca2+ Crystal for Positron Emission Tomography","authors":"I. M. Ermochenkov,&nbsp;Yu. D. Zavartsev,&nbsp;A. I. Zagumennyi,&nbsp;O. V. Yurasova,&nbsp;I. V. Morozov,&nbsp;D. V. Serebryakov","doi":"10.3103/S1068335623601231","DOIUrl":"10.3103/S1068335623601231","url":null,"abstract":"<p>Highly efficient scintillation Lu<sub>2</sub>SiO<sub>5 ‒</sub> <sub><i>z</i></sub>:Y<sup>3+</sup>:Ce<sup>3+</sup>:Ca<sup>2+</sup> crystals are grown from 20 to 85% of the initial melt using the Czochralski method. Crystallization of less than 50% of the melt residues in the iridium crucible leads to its deformation and short operating time. Optimized parameters of the growth process and the composition of the initial melt make it possible to grow crystalline boules with a diameter of 75‒80 mm. The scintillation properties of elements measuring 3 × 3 × 20 mm for time-of-flight positron emission tomography (TOF PET), made of the upper and lower parts of a boule weighing 5 kg, are studied.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140572836","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}
引用次数: 0
Influence of Adjacent Nonsuperconducting Layers on Critical Parameters of an Inhomogeneous Superconducting Layer 相邻非超导层对非均质超导层临界参数的影响
IF 0.6 4区 物理与天体物理
Bulletin of the Lebedev Physics Institute Pub Date : 2024-04-04 DOI: 10.3103/S1068335623600407
P. I. Bezotosnyi, K. A. Dmitrieva
{"title":"Influence of Adjacent Nonsuperconducting Layers on Critical Parameters of an Inhomogeneous Superconducting Layer","authors":"P. I. Bezotosnyi,&nbsp;K. A. Dmitrieva","doi":"10.3103/S1068335623600407","DOIUrl":"10.3103/S1068335623600407","url":null,"abstract":"<p>The paper describes a method for calculating critical parameters of an inhomogeneous superconducting layer surrounded by nonsuperconducting layers. The calculation is performed using Ginzburg‒Landau equations modified for a thickness-inhomogeneous superconducting layer. The effect of adjacent nonsuperconducting layers is specified using general boundary conditions to these equations. Dependences of the critical current of a superconducting layer on the external magnetic field is calculated numerically. It is shown that for a layer of inhomogeneous thickness, in the model of which the effect of adjacent layers is introduced, an estimate of the critical current yields lower values than those for a homogeneous layer without any influence of boundaries. It is found that at a certain value of the external magnetic field, the critical current is independent of the degree of the superconducting layer inhomogeneity. In this case, the influence of adjacent layers on its superconducting state does not lead to a significant change in the value of this field.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140591725","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}
引用次数: 0
The DANSS Experiment: Recent Results and Perspective DANSS 实验：最新成果与展望
IF 0.6 4区 物理与天体物理
Bulletin of the Lebedev Physics Institute Pub Date : 2024-04-04 DOI: 10.3103/S1068335623601796
I. G. Alekseev
{"title":"The DANSS Experiment: Recent Results and Perspective","authors":"I. G. Alekseev","doi":"10.3103/S1068335623601796","DOIUrl":"10.3103/S1068335623601796","url":null,"abstract":"<p>The DANSS experiment is a scintillation spectrometer of reactor antineutrinos placed at the Unit 4 reactor of the Kalinin Nuclear Power Plant about 300 km northwest of Moscow. The main fundamental aim of the experiment is search for sterile neutrinos. The experiment was commissioned in April 2016 and regular data taking has been carried out since October 2016. 7.7 million of inverse beta-decay events have been collected by March 2023. A vast exclusion area of the sterile neutrino parameters was set. In the region of the best sensitivity the limit reached <span>({text{sin}}2{{theta }^{2}} = 5 times {{10}^{{ - 3}}})</span>. The reactor power has been monitored for 6.5 years. The dispersion that is not related to single measurement statistics is below 0.5%, which gives an upper estimate of the precision of the standard NPP power measurements at the level of at least 0.5%. New scintillator detectors designed to upgrade the DANSS facility were tested at an accelerator beam. Light yield better than 140 ph.e./MeV was obtained. This paper describes the results obtained during the last year and the facility upgrade plans.</p>","PeriodicalId":503,"journal":{"name":"Bulletin of the Lebedev Physics Institute","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140591724","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}
引用次数: 0
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