L. Giuffrida, V. Istokskaia, A. Picciotto, V. Kantarelou, M. Barozzi, R. Dell`Anna, M. Divoký, O. Denk, D. Giubertoni, F. Grepl, A. Hadjikyriacou, M. Hanus, J. Krása, M. Kucharik, T. Levato, P. Navratil, J. Pilar, F. Schillaci, S. Stanček, M. Tosca, M. Tryus, A. Velyhan, A. Lucianetti, T. Mocek, D. Margarone
An experimental platform for laser-driven ion (sub-MeV) acceleration and potential applications was commissioned at the HiLASE laser facility. The auxiliary beam of the Bivoj laser system operating at a GW level peak power (~10 J in 5–10 ns) and 1–10 Hz repetition rate enabled a stable production of high-current ion beams of multiple species (Al, Ti, Fe, Si, Cu, and Sn). The produced laser–plasma ion sources were fully characterized against the laser intensity on the target (1013–1015 W/cm2) by varying the laser energy, focal spot size, and pulse duration. The versatility and tuneability of such high-repetition-rate laser–plasma ion sources are of potential interest for user applications. Such a statistically accurate study was facilitated by the large amount of data acquired at the high repetition rate (1–10 Hz) provided by the Bivoj laser system.
{"title":"A Platform for Laser-Driven Ion Sources Generated with Nanosecond Laser Pulses in the Intensity Range of 1013–1015 W/cm2","authors":"L. Giuffrida, V. Istokskaia, A. Picciotto, V. Kantarelou, M. Barozzi, R. Dell`Anna, M. Divoký, O. Denk, D. Giubertoni, F. Grepl, A. Hadjikyriacou, M. Hanus, J. Krása, M. Kucharik, T. Levato, P. Navratil, J. Pilar, F. Schillaci, S. Stanček, M. Tosca, M. Tryus, A. Velyhan, A. Lucianetti, T. Mocek, D. Margarone","doi":"10.3390/qubs8010005","DOIUrl":"https://doi.org/10.3390/qubs8010005","url":null,"abstract":"An experimental platform for laser-driven ion (sub-MeV) acceleration and potential applications was commissioned at the HiLASE laser facility. The auxiliary beam of the Bivoj laser system operating at a GW level peak power (~10 J in 5–10 ns) and 1–10 Hz repetition rate enabled a stable production of high-current ion beams of multiple species (Al, Ti, Fe, Si, Cu, and Sn). The produced laser–plasma ion sources were fully characterized against the laser intensity on the target (1013–1015 W/cm2) by varying the laser energy, focal spot size, and pulse duration. The versatility and tuneability of such high-repetition-rate laser–plasma ion sources are of potential interest for user applications. Such a statistically accurate study was facilitated by the large amount of data acquired at the high repetition rate (1–10 Hz) provided by the Bivoj laser system.","PeriodicalId":31879,"journal":{"name":"Quantum Beam Science","volume":"53 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139441204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A sample of 18 double-relief coins from different poleis of Magna Graecia and ancient Italy has been analysed using a handheld XRF spectrometer directly inside the Museo Provinciale Campano (Capua, Italy). The data analysis shows that (i) the main elements are Ag and Cu, indicating that the coins are of high fineness (average Ag 95.7%), (ii) trace elements can help to characterise the coins, (iii) a superficial chemically altered layer (corrosion) is absent, (iv) the values of ratio Ag Kα/Lα evidence the presence of an enrichment layer on the surface of silver or subaerata in some coins. Multivariate statistical analysis and graph analysis allowed the coins to be assigned to different groups with the highest possible accuracy on the basis of the chemical data obtained and models to be constructed to classify the coins according to their historical periods.
{"title":"Double-Relief Silver Coins Minted in the Greek Colonies (444–390/340–280/270 BC) of Southern Italy Analysed by XRF","authors":"J. Brocchieri, R. Vitale, Carlo Sabbarese","doi":"10.3390/qubs8010002","DOIUrl":"https://doi.org/10.3390/qubs8010002","url":null,"abstract":"A sample of 18 double-relief coins from different poleis of Magna Graecia and ancient Italy has been analysed using a handheld XRF spectrometer directly inside the Museo Provinciale Campano (Capua, Italy). The data analysis shows that (i) the main elements are Ag and Cu, indicating that the coins are of high fineness (average Ag 95.7%), (ii) trace elements can help to characterise the coins, (iii) a superficial chemically altered layer (corrosion) is absent, (iv) the values of ratio Ag Kα/Lα evidence the presence of an enrichment layer on the surface of silver or subaerata in some coins. Multivariate statistical analysis and graph analysis allowed the coins to be assigned to different groups with the highest possible accuracy on the basis of the chemical data obtained and models to be constructed to classify the coins according to their historical periods.","PeriodicalId":31879,"journal":{"name":"Quantum Beam Science","volume":"32 4","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139157947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Probabilistic fracture mechanics (PFM) is increasingly recognized as a viable approach for evaluating the structural integrity of nuclear components, such as piping, primarily affected by stress corrosion cracking (SCC). PFM analysis requires several input parameters, among which welding residual stress is critically important due to its significant influence on SCC initiation and propagation. Recently, a novel technique involving a double-exposure method (DEM) utilizing synchrotron X-rays was introduced as an effective means for measuring welding residual stress with high spatial resolution. In this paper, we applied DEM to assess the residual stress of a plate specimen, which was extracted from a welded pipe through electrical discharge machining. Consequently, detailed stress maps under a plane stress state were generated. Additionally, the residual stress distributions in the welded pipe under a triaxial stress state were evaluated using neutron diffraction. Based on these findings, we proposed a methodology to acquire detailed stress maps of welded pipes by combining high-energy synchrotron X-rays and neutron diffraction.
人们日益认识到，概率断裂力学（PFM）是评估主要受应力腐蚀开裂（SCC）影响的管道等核部件结构完整性的一种可行方法。PFM 分析需要几个输入参数，其中焊接残余应力至关重要，因为它对 SCC 的产生和扩展有重大影响。最近，一种利用同步辐射 X 射线的双曝光法 (DEM) 的新技术被引入，成为一种以高空间分辨率测量焊接残余应力的有效手段。在本文中，我们应用 DEM 评估了通过放电加工从焊接管道中提取的板材试样的残余应力。因此，生成了平面应力状态下的详细应力图。此外，我们还利用中子衍射评估了焊接管道在三轴应力状态下的残余应力分布。基于这些发现，我们提出了一种结合高能同步辐射 X 射线和中子衍射来获取焊接管道详细应力图的方法。
{"title":"Stress Measurement of Stainless Steel Piping Welds by Complementary Use of High-Energy Synchrotron X-rays and Neutrons","authors":"Yasufumi Miura, Kenji Suzuki, Satoshi Morooka, Takahisa Shobu","doi":"10.3390/qubs8010001","DOIUrl":"https://doi.org/10.3390/qubs8010001","url":null,"abstract":"Probabilistic fracture mechanics (PFM) is increasingly recognized as a viable approach for evaluating the structural integrity of nuclear components, such as piping, primarily affected by stress corrosion cracking (SCC). PFM analysis requires several input parameters, among which welding residual stress is critically important due to its significant influence on SCC initiation and propagation. Recently, a novel technique involving a double-exposure method (DEM) utilizing synchrotron X-rays was introduced as an effective means for measuring welding residual stress with high spatial resolution. In this paper, we applied DEM to assess the residual stress of a plate specimen, which was extracted from a welded pipe through electrical discharge machining. Consequently, detailed stress maps under a plane stress state were generated. Additionally, the residual stress distributions in the welded pipe under a triaxial stress state were evaluated using neutron diffraction. Based on these findings, we proposed a methodology to acquire detailed stress maps of welded pipes by combining high-energy synchrotron X-rays and neutron diffraction.","PeriodicalId":31879,"journal":{"name":"Quantum Beam Science","volume":"44 4","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139164409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The acquisition of elemental and chemical distribution images on the surface of cultural heritage objects has provided us new insights into our past. The techniques commonly employed, such as macroscopic X-ray fluorescence imaging (MA-XRF), in general require pointwise or whisk-broom scanning of an object under constant measurement geometry for optimal results. Most scanners in this field use stacked linear motorized stages, which are a proven solution for 2D sample positioning. Instead of these serial systems, we propose the use of a parallel cable robot to position the measurement head relative to the object investigated. In this article, we illustrate the significance of the issue and present our own cable robot prototype and test its capabilities, but also discuss the current shortcomings of the concept. With this, we demonstrate the potential of cable robots as platforms for MA-XRF and similar imaging techniques.
获取文物表面的元素和化学分布图像为我们了解历史提供了新的视角。常用的技术，如宏观 X 射线荧光成像（MA-XRF），一般需要在恒定的测量几何条件下对物体进行点扫描或拂扫式扫描，以获得最佳结果。该领域的大多数扫描仪都使用堆叠式线性电动平台，这是一种行之有效的二维样品定位解决方案。与这些串行系统相比，我们建议使用平行电缆机器人来定位与被测物体相对应的测量头。在这篇文章中，我们阐述了这一问题的重要性，并展示了我们自己的电缆机器人原型，测试了它的能力，同时也讨论了这一概念目前存在的不足。由此，我们证明了缆索机器人作为 MA-XRF 和类似成像技术平台的潜力。
{"title":"Cable Robots as Conventional Linear Stage Alternatives for the Investigation of Complex-Shaped Objects via Macroscopic X-ray Fluorescence Imaging","authors":"Matthias Alfeld, Philipp Tempel, V. van der Wijk","doi":"10.3390/qubs7040037","DOIUrl":"https://doi.org/10.3390/qubs7040037","url":null,"abstract":"The acquisition of elemental and chemical distribution images on the surface of cultural heritage objects has provided us new insights into our past. The techniques commonly employed, such as macroscopic X-ray fluorescence imaging (MA-XRF), in general require pointwise or whisk-broom scanning of an object under constant measurement geometry for optimal results. Most scanners in this field use stacked linear motorized stages, which are a proven solution for 2D sample positioning. Instead of these serial systems, we propose the use of a parallel cable robot to position the measurement head relative to the object investigated. In this article, we illustrate the significance of the issue and present our own cable robot prototype and test its capabilities, but also discuss the current shortcomings of the concept. With this, we demonstrate the potential of cable robots as platforms for MA-XRF and similar imaging techniques.","PeriodicalId":31879,"journal":{"name":"Quantum Beam Science","volume":"73 3","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139253713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Almaz Nazarov, Alexey Maslov, Elena A. Korznikova, Kamil Ramazanov
This article explores the utilization of cathodic-arc deposition Cr-Al overlay coatings as oxidation protection for Ti-Al-Nb intermetallic alloys. The primary objective is to investigate PVD Al-Cr coatings deposited via cathodic-arc deposition without subsequent vacuum annealing. The microstructure, phase, and chemical composition of the coatings were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction analysis. Isothermal exposure of samples in a laboratory air furnace was conducted, revealing the efficacy of Cr-Al coatings in protecting the Ti49-11Al-40Nb-1.5Zr-0.75V-0.75Mo-0.2Si (mass%) intermetallic alloy VTI-4 against oxidation. The findings highlight that the as-deposited coatings possess a layered structure and contain Al-Cr intermetallics. Post-exposure to the furnace without prior vacuum annealing results in coatings exhibiting a porous microstructure, raising concerns regarding oxidation protection. This investigation of Cr-Al coatings on a VTI-4 alloy substrate yields valuable insights into their nanolaminate structure and challenges associated with aluminum droplet fractions. The proposed additional vacuum heat treatment at 650 °C for 500 h effectively homogenizes the coating, leading to predominant Cr2Al and Ti-Al phases. Additionally, the formation of diffusion layers at the “coating–substrate” interface and the presence of oxide barriers contribute to the coatings’ heat resistance. Our research introduces possibilities for tailoring coating properties for specific high-temperature applications in aerospace, energy, or industrial contexts. Further refinement of the heat treatment process offers the potential for developing advanced coatings with enhanced performance characteristics.
本文探讨了如何利用阴极电弧沉积铬-铝覆盖层作为钛-铝-铌金属间合金的氧化保护。主要目的是研究通过阴极电弧沉积沉积的 PVD 铝-铬涂层，而无需随后进行真空退火。使用扫描电子显微镜、能量色散 X 射线光谱和 X 射线衍射分析对涂层的微观结构、相和化学成分进行了表征。在实验室空气炉中对样品进行了等温暴露，发现铬-铝涂层在保护 Ti49-11Al-40Nb-1.5Zr-0.75V-0.75Mo-0.2Si（质量百分比）金属间合金 VTI-4 免受氧化方面的功效。研究结果表明，沉积涂层具有层状结构，并含有铝铬金属间化合物。在未进行真空退火的情况下将镀层暴露于炉中，会导致镀层呈现多孔微观结构，从而引发对氧化保护的担忧。通过对 VTI-4 合金基材上的铬-铝涂层的研究，可以深入了解其纳米层状结构以及与铝液滴分数相关的挑战。建议在 650 °C 下进行 500 小时的额外真空热处理可有效均匀镀层，从而形成主要的 Cr2Al 和 Ti-Al 相。此外，"涂层-基底 "界面扩散层的形成和氧化物屏障的存在也有助于提高涂层的耐热性。我们的研究为航空航天、能源或工业领域的特定高温应用提供了定制涂层特性的可能性。热处理工艺的进一步完善为开发具有更高性能特征的先进涂层提供了可能。
{"title":"Chromium–Aluminum Coatings for Oxidation Protection of Titanium–Aluminum Intermetallic Alloys","authors":"Almaz Nazarov, Alexey Maslov, Elena A. Korznikova, Kamil Ramazanov","doi":"10.3390/qubs7040036","DOIUrl":"https://doi.org/10.3390/qubs7040036","url":null,"abstract":"This article explores the utilization of cathodic-arc deposition Cr-Al overlay coatings as oxidation protection for Ti-Al-Nb intermetallic alloys. The primary objective is to investigate PVD Al-Cr coatings deposited via cathodic-arc deposition without subsequent vacuum annealing. The microstructure, phase, and chemical composition of the coatings were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction analysis. Isothermal exposure of samples in a laboratory air furnace was conducted, revealing the efficacy of Cr-Al coatings in protecting the Ti49-11Al-40Nb-1.5Zr-0.75V-0.75Mo-0.2Si (mass%) intermetallic alloy VTI-4 against oxidation. The findings highlight that the as-deposited coatings possess a layered structure and contain Al-Cr intermetallics. Post-exposure to the furnace without prior vacuum annealing results in coatings exhibiting a porous microstructure, raising concerns regarding oxidation protection. This investigation of Cr-Al coatings on a VTI-4 alloy substrate yields valuable insights into their nanolaminate structure and challenges associated with aluminum droplet fractions. The proposed additional vacuum heat treatment at 650 °C for 500 h effectively homogenizes the coating, leading to predominant Cr2Al and Ti-Al phases. Additionally, the formation of diffusion layers at the “coating–substrate” interface and the presence of oxide barriers contribute to the coatings’ heat resistance. Our research introduces possibilities for tailoring coating properties for specific high-temperature applications in aerospace, energy, or industrial contexts. Further refinement of the heat treatment process offers the potential for developing advanced coatings with enhanced performance characteristics.","PeriodicalId":31879,"journal":{"name":"Quantum Beam Science","volume":"16 3","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139257887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andrew G. Manning, Shinichiro Yano, Sojeong Kim, Won Bo Lee, Soo-Hyung Choi, Nicolas R. de Souza
Polarisation analysis for neutron scattering experiments is a powerful tool suitable for a wide variety of studies, including soft-matter samples which have no bulk magnetic behaviour and/or a significant hydrogen content. Here, we describe a method to leverage the versatility and spin-polarisation capabilities of a cold triple-axis spectrometer to perform a measurement to separate coherent and incoherent neutron scattering for a non-magnetic sample in the quasielastic neutron scattering (QENS) regime. Such measurements are complementary to unpolarised QENS measurements, which may typically be performed on a backscattering or time-of-flight spectrometer instrument where polarisation analysis can be significantly more difficult to achieve, and utilise the strengths of each type of instrument.
{"title":"Identifying the Spin-Incoherent Contribution to Quasielastic Neutron Scattering with a Cold Triple-Axis Spectrometer","authors":"Andrew G. Manning, Shinichiro Yano, Sojeong Kim, Won Bo Lee, Soo-Hyung Choi, Nicolas R. de Souza","doi":"10.3390/qubs7040035","DOIUrl":"https://doi.org/10.3390/qubs7040035","url":null,"abstract":"Polarisation analysis for neutron scattering experiments is a powerful tool suitable for a wide variety of studies, including soft-matter samples which have no bulk magnetic behaviour and/or a significant hydrogen content. Here, we describe a method to leverage the versatility and spin-polarisation capabilities of a cold triple-axis spectrometer to perform a measurement to separate coherent and incoherent neutron scattering for a non-magnetic sample in the quasielastic neutron scattering (QENS) regime. Such measurements are complementary to unpolarised QENS measurements, which may typically be performed on a backscattering or time-of-flight spectrometer instrument where polarisation analysis can be significantly more difficult to achieve, and utilise the strengths of each type of instrument.","PeriodicalId":31879,"journal":{"name":"Quantum Beam Science","volume":"65 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136283477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MgB2 represents a hexagonal superconductive material renowned for its straightforward composition, which has facilitated the development of cost-effective practical wires. Its capacity to function at temperatures as low as liquid hydrogen (LH2) has made it a prominent candidate as wire material for the coils of next-generation fusion reactors. Much like other superconducting wires, a prevalent issue arises when these wires are employed in coils, wherein electromagnetic forces induce tensile stress and strain within the wire. This, in turn, diminishes the critical current, which is the maximum current capable of flowing within the generated magnetic field and strain. The techniques and methods for accurately measuring the actual strain on the filaments are of paramount importance. While strain measurements have been conducted with synchrotron radiation and neutrons for other practical wires in the past, no such measurements have been undertaken for MgB2. Presumably, this lack of measurement is attributed to its relatively greater thickness, making it less suitable for synchrotron radiation measurements. Additionally, the high absorption cross-section of the included boron-10 poses challenges in obtaining elastic scattering data for neutron measurements. In response, we fabricated a wire enriched with boron-11, an isotope with a smaller neutron absorption cross-section. We then embarked on the endeavor to measure its strain under tensile loading using pulsed neutrons. Consequently, we succeeded in obtaining changes in the lattice constant under tensile loading through Rietveld analysis. This marks the inaugural instance of strain measurement on an MgB2 filament, signifying a significant milestone in superconductivity research.
{"title":"Measurement of Mechanical Behavior of 11B-Enriched MgB2 Wire Using a Pulsed Neutron Source","authors":"Shutaro Machiya, Kozo Osamura, Yoshimitsu Hishinuma, Hiroyasu Taniguchi, Stefanus Harjo, Takuro Kawasaki","doi":"10.3390/qubs7040034","DOIUrl":"https://doi.org/10.3390/qubs7040034","url":null,"abstract":"MgB2 represents a hexagonal superconductive material renowned for its straightforward composition, which has facilitated the development of cost-effective practical wires. Its capacity to function at temperatures as low as liquid hydrogen (LH2) has made it a prominent candidate as wire material for the coils of next-generation fusion reactors. Much like other superconducting wires, a prevalent issue arises when these wires are employed in coils, wherein electromagnetic forces induce tensile stress and strain within the wire. This, in turn, diminishes the critical current, which is the maximum current capable of flowing within the generated magnetic field and strain. The techniques and methods for accurately measuring the actual strain on the filaments are of paramount importance. While strain measurements have been conducted with synchrotron radiation and neutrons for other practical wires in the past, no such measurements have been undertaken for MgB2. Presumably, this lack of measurement is attributed to its relatively greater thickness, making it less suitable for synchrotron radiation measurements. Additionally, the high absorption cross-section of the included boron-10 poses challenges in obtaining elastic scattering data for neutron measurements. In response, we fabricated a wire enriched with boron-11, an isotope with a smaller neutron absorption cross-section. We then embarked on the endeavor to measure its strain under tensile loading using pulsed neutrons. Consequently, we succeeded in obtaining changes in the lattice constant under tensile loading through Rietveld analysis. This marks the inaugural instance of strain measurement on an MgB2 filament, signifying a significant milestone in superconductivity research.","PeriodicalId":31879,"journal":{"name":"Quantum Beam Science","volume":"97 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135872626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The collective acceleration of helium ions from its residual atmosphere in the Luce diode was studied at helium pressures from 0.13 to 0.23 Pa. The energy of accelerated ions was determined from the drift velocity of the virtual cathode accelerating the ions. The number of 4He was determined by radioactivities of 13N and 30P induced in h-BN and Al targets via the nuclear reactions 10B(α,n)13N and 27Al(α,n)30P. The efficiency of capturing 4He ions in collective acceleration from the residual helium atmosphere was estimated as 0.25%. With increasing helium pressure above 0.15 Pa, the energy of the main ion group noticeably decreased to 0.46 MeV/amu compared to the acceleration from a usual residual atmosphere (~0.6 MeV/amu); however, the probability of ion acceleration to a specific energy of up to 1.57 MeV/amu increased significantly. Such increases in the ion energy were accompanied by the appearance of the signal of the second virtual cathode 7–9 ns after the appearance of the first virtual cathode.
{"title":"Collective Acceleration of Helium Ions from Its Residual Atmosphere in a Luce Diode","authors":"Vladislav Ryzhkov, Mikhail Zhuravlev, Gennady Remnev","doi":"10.3390/qubs7040033","DOIUrl":"https://doi.org/10.3390/qubs7040033","url":null,"abstract":"The collective acceleration of helium ions from its residual atmosphere in the Luce diode was studied at helium pressures from 0.13 to 0.23 Pa. The energy of accelerated ions was determined from the drift velocity of the virtual cathode accelerating the ions. The number of 4He was determined by radioactivities of 13N and 30P induced in h-BN and Al targets via the nuclear reactions 10B(α,n)13N and 27Al(α,n)30P. The efficiency of capturing 4He ions in collective acceleration from the residual helium atmosphere was estimated as 0.25%. With increasing helium pressure above 0.15 Pa, the energy of the main ion group noticeably decreased to 0.46 MeV/amu compared to the acceleration from a usual residual atmosphere (~0.6 MeV/amu); however, the probability of ion acceleration to a specific energy of up to 1.57 MeV/amu increased significantly. Such increases in the ion energy were accompanied by the appearance of the signal of the second virtual cathode 7–9 ns after the appearance of the first virtual cathode.","PeriodicalId":31879,"journal":{"name":"Quantum Beam Science","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135266047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tensile deformation in situ neutron diffraction of an extruded AZ31 alloy was performed to validate conventional procedures and to develop new procedures for stress evaluation from lattice strains by diffraction measurements of HCP-structured magnesium alloys. Increases in the lattice strains with respect to the applied true stress after yielding largely vary among [hk.l] grains. Some [hk.l] grains have little or no increase in lattice strain, making it difficult to use the conventional procedures to determine the average phase strain by using lattice constants or by averaging several lattice strains. The newly proposed procedure of stress evaluation from the lattice strains shows very high accuracy and reliability by weighting the volume fraction of [hk.l] grains and evaluating them in many [hk.l] orientations in addition to multiplication by the diffraction elastic constant. When multiple hk.l peaks cannot be obtained simultaneously, we recommend to use the 12.1 peak for stress evaluation. The lattice strain value evaluated from the 12.1 peak shows a good linear relationship with the applied true stress for the whole deformation region.
{"title":"Stress Evaluation Method by Neutron Diffraction for HCP-Structured Magnesium Alloy","authors":"Stefanus Harjo, Wu Gong, Takuro Kawasaki","doi":"10.3390/qubs7040032","DOIUrl":"https://doi.org/10.3390/qubs7040032","url":null,"abstract":"Tensile deformation in situ neutron diffraction of an extruded AZ31 alloy was performed to validate conventional procedures and to develop new procedures for stress evaluation from lattice strains by diffraction measurements of HCP-structured magnesium alloys. Increases in the lattice strains with respect to the applied true stress after yielding largely vary among [hk.l] grains. Some [hk.l] grains have little or no increase in lattice strain, making it difficult to use the conventional procedures to determine the average phase strain by using lattice constants or by averaging several lattice strains. The newly proposed procedure of stress evaluation from the lattice strains shows very high accuracy and reliability by weighting the volume fraction of [hk.l] grains and evaluating them in many [hk.l] orientations in addition to multiplication by the diffraction elastic constant. When multiple hk.l peaks cannot be obtained simultaneously, we recommend to use the 12.1 peak for stress evaluation. The lattice strain value evaluated from the 12.1 peak shows a good linear relationship with the applied true stress for the whole deformation region.","PeriodicalId":31879,"journal":{"name":"Quantum Beam Science","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135858396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Silicon carbide junction field-effect transistors (SiC JFETs) are promising candidates as devices applicable to radiation conditions, such as the decommissioning of nuclear facilities or the space environment. We investigate the origin of the threshold volage (Vth) shift and hysteresis of differently structured SiC JFETs. A large positive Vth shift and hysteresis are observed for a depletion-type JFET with a larger depletion layer width. With changing the sweep range of the gate voltage and depletion width, the Vth shift was positively proportional to the difference between the channel depth and depletion width (channel depth–gate depletion width). By illuminating the sub-band gap light, the Vth of the irradiated depletion JFETs recovers close to nonirradiated ones, while a smaller shift and hysteresis are observed for the enhancement type with a narrower width. It can be interpreted that positive charges generated in a gate depletion layer cause a positive Vth shift. When they are swept out from the depletion layer and trapped in the channel, this gives rise to a further Vth shift and hysteresis in gamma-irradiated SiC JFETs.
{"title":"Influence of Gate Depletion Layer Width on Radiation Resistance of Silicon Carbide Junction Field-Effect Transistors","authors":"Akinori Takeyama, Takahiro Makino, Yasunori Tanaka, Shin-Ichiro Kuroki, Takeshi Ohshima","doi":"10.3390/qubs7040031","DOIUrl":"https://doi.org/10.3390/qubs7040031","url":null,"abstract":"Silicon carbide junction field-effect transistors (SiC JFETs) are promising candidates as devices applicable to radiation conditions, such as the decommissioning of nuclear facilities or the space environment. We investigate the origin of the threshold volage (Vth) shift and hysteresis of differently structured SiC JFETs. A large positive Vth shift and hysteresis are observed for a depletion-type JFET with a larger depletion layer width. With changing the sweep range of the gate voltage and depletion width, the Vth shift was positively proportional to the difference between the channel depth and depletion width (channel depth–gate depletion width). By illuminating the sub-band gap light, the Vth of the irradiated depletion JFETs recovers close to nonirradiated ones, while a smaller shift and hysteresis are observed for the enhancement type with a narrower width. It can be interpreted that positive charges generated in a gate depletion layer cause a positive Vth shift. When they are swept out from the depletion layer and trapped in the channel, this gives rise to a further Vth shift and hysteresis in gamma-irradiated SiC JFETs.","PeriodicalId":31879,"journal":{"name":"Quantum Beam Science","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136211391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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