Mo L-shell x rays have been measured for the bombardment of highly charged heavy Ar11+ ions in the energy range of 1 MeV − 3 MeV. The new experimental data for individual L-subshell and total L-shell x-ray production cross sections were obtained and compared with the theoretical calculations of BEA, PWBA, ECPSSR, ECUSAR, and that of BEA modified by the Coulomb repulsion (CR) and effective nuclear charge (Zeff). The effect of multiple ionization in the atomic parameters was considered. The smaller the fluorescence yield of single ionization, the greater the enhancement of x-ray radiation caused by multiple ionization. On the whole, the BEA-Zeff-CR-MI simulations adopting appropriate multiple ionization atomic parameters are found to be in good agreement with the data.
在1 MeV−3 MeV的能量范围内，测量了高电荷重Ar11+离子轰击Mo l壳层 x 射线。得到了单个l -亚壳层和总l -壳层x射线产生截面的新实验数据，并与BEA、PWBA、ECPSSR、ECUSAR以及经库仑斥力（CR）和有效核电荷（Zeff）修饰的BEA的理论计算结果进行了比较。考虑了多重电离对原子参数的影响。单次电离的荧光产额越小，多次电离对x射线辐射的增强作用越大。总的来说，采用适当的多电离原子参数的BEA-Zeff-CR-MI模拟结果与实际数据吻合较好。
{"title":"Mo L-shell x-ray production cross section by heavy Ar11+ ions near the Bohr velocity","authors":"Jing Wei , Xianming Zhou , Rui Cheng , Changhui Liang , Yanning Zhang , Xiaoan Zhang , Yongtao Zhao","doi":"10.1016/j.nimb.2025.165944","DOIUrl":"10.1016/j.nimb.2025.165944","url":null,"abstract":"<div><div>Mo L-shell x rays have been measured for the bombardment of highly charged heavy Ar<sup>11+</sup> ions in the energy range of 1 MeV − 3 MeV. The new experimental data for individual L-subshell and total L-shell x-ray production cross sections were obtained and compared with the theoretical calculations of BEA, PWBA, ECPSSR, ECUSAR, and that of BEA modified by the Coulomb repulsion (CR) and effective nuclear charge (Z<sub>eff</sub>). The effect of multiple ionization in the atomic parameters was considered. The smaller the fluorescence yield of single ionization, the greater the enhancement of x-ray radiation caused by multiple ionization. On the whole, the BEA-Z<sub>eff</sub>-CR-MI simulations adopting appropriate multiple ionization atomic parameters are found to be in good agreement with the data.</div></div>","PeriodicalId":19380,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms","volume":"570 ","pages":"Article 165944"},"PeriodicalIF":1.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01Epub Date: 2025-11-25DOI: 10.1016/j.nimb.2025.165956
Huan Tan , Yumeng Yang , Yaning Gao , Yun Li , Chengyuan Wu , Zhimei Yang , Weihao Lin , Lijun Wang , Min Gong , Mingmin Huang , Yao Ma
The effects of 2150 MeV 84Kr ion irradiation at different irradiation doses on the phenomenon of negative dielectric constant in Si-based PiN devices were studied. SRIM simulation results demonstrated that the incident ion energy was mainly dissipated in the form of electron energy loss. The electrical characterization analysis indicated that as the irradiation dose increased, the forward conduction resistance and the effective carrier concentration (ND) of device exhibited a decreasing trend. The series resistance (Rs) gradually increased from 1.05 Ω to 1.54 Ω. The ideality factor (n) showed a significant increase in irradiated samples compared to unirradiated. However, the irradiation dose changes did not have a significant impact on n. Within the frequency range of 10^3–10^5 Hz, the real part of the dielectric constant decreased with increasing irradiation dose and reached negative value. Within the frequency range of 10^6–10^7 Hz, it gradually approached to zero with the variation of the irradiation dose. The dielectric loss (imaginary part) increased in the low frequency range of 1–10 Hz. The Deep Level Transient Spectroscopy (DLTS) analysis revealed a non-monotonic relationship between defects and ion dose. These findings are of great importance in revealing the micro-mechanism of irradiation induced negative dielectric constant and in developing potential applications of silicon materials and silicon devices.
{"title":"84Kr heavy ion irradiation dose dependent effects on negative dielectric constant of Si-based PiN","authors":"Huan Tan , Yumeng Yang , Yaning Gao , Yun Li , Chengyuan Wu , Zhimei Yang , Weihao Lin , Lijun Wang , Min Gong , Mingmin Huang , Yao Ma","doi":"10.1016/j.nimb.2025.165956","DOIUrl":"10.1016/j.nimb.2025.165956","url":null,"abstract":"<div><div>The effects of 2150 MeV <sup>84</sup>Kr ion irradiation at different irradiation doses on the phenomenon of negative dielectric constant in Si-based PiN devices were studied. SRIM simulation results demonstrated that the incident ion energy was mainly dissipated in the form of electron energy loss. The electrical characterization analysis indicated that as the irradiation dose increased, the forward conduction resistance and the effective carrier concentration (<em>N<sub>D</sub></em>) of device exhibited a decreasing trend. The series resistance (<em>R<sub>s</sub></em>) gradually increased from 1.05 Ω to 1.54 Ω. The ideality factor (n) showed a significant increase in irradiated samples compared to unirradiated. However, the irradiation dose changes did not have a significant impact on <em>n</em>. Within the frequency range of 10^3–10^5 Hz, the real part of the dielectric constant decreased with increasing irradiation dose and reached negative value. Within the frequency range of 10^6–10^7 Hz, it gradually approached to zero with the variation of the irradiation dose. The dielectric loss (imaginary part) increased in the low frequency range of 1–10 Hz. The Deep Level Transient Spectroscopy (DLTS) analysis revealed a non-monotonic relationship between defects and ion dose. These findings are of great importance in revealing the micro-mechanism of irradiation induced negative dielectric constant and in developing potential applications of silicon materials and silicon devices.</div></div>","PeriodicalId":19380,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms","volume":"570 ","pages":"Article 165956"},"PeriodicalIF":1.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145620825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01Epub Date: 2025-11-10DOI: 10.1016/j.nimb.2025.165935
Zuzana Slavkovská , Ferdos Dastgiri , L. Keith Fifield , Michaela B. Froehlich , Michael A.C. Hotchkis , Dominik Koll , Silke Merchel , Stefan Pavetich , Stephen G. Tims , Anton Wallner
Sodium iodide crystals doped with thallium NaI(Tl) can be used as detector material for direct dark matter detection by taking advantage of their particle detection properties of scintillation. In order to achieve this, it is crucial that these crystals are of ultra-high purity. Radioimpurities within the crystals may potentially mimic dark matter signals and thus must be quantified, minimised where possible and distinguished from real events. Abundances of radionuclides 129I and 210Pb, which are dominant sources of radioimpurities in NaI(Tl) crystals, were measured using accelerator mass spectrometry at the Australian National University (ANU) and the Australian Nuclear Science and Technology Organisation (ANSTO). NaI powder chemically processed to AgI, and, for the first time, unprocessed NaI powder, were shown to be suitable as AMS targets. A consistent 129I/127I ratio of (2.0 0.3) 10−13 was measured in three different commercially available NaI powders, one order of magnitude higher than the measured blank with (1.4 0.3) 10−14. Therefore, it was concluded that the choice of NaI powder has a negligible influence on the 129I contribution to low-background dark matter experiments. For 210Pb, different Pb molecular ion species were assessed with PbO being the preferred species and applied to investigate different lead oxide compounds for their suitability as Pb carriers. A 210Pb/Pb isotopic ratio of (3.6 ) 10−15 was measured in PbO powder. This met the required lower activity limit of 210Pb when adding 1 mg of stable lead into 1 kg of NaI(Tl) powder with a desired maximum 210Pb/Pb isotopic ratio of 1 10−14. These results indicate the suitability of the investigated PbO as a potential carrier for incorporation with Pb extracted from NaI used for dark matter experiments.
{"title":"Dark matter detector radioimpurities 129I and 210Pb measured with accelerator mass spectrometry","authors":"Zuzana Slavkovská , Ferdos Dastgiri , L. Keith Fifield , Michaela B. Froehlich , Michael A.C. Hotchkis , Dominik Koll , Silke Merchel , Stefan Pavetich , Stephen G. Tims , Anton Wallner","doi":"10.1016/j.nimb.2025.165935","DOIUrl":"10.1016/j.nimb.2025.165935","url":null,"abstract":"<div><div>Sodium iodide crystals doped with thallium NaI(Tl) can be used as detector material for direct dark matter detection by taking advantage of their particle detection properties of scintillation. In order to achieve this, it is crucial that these crystals are of ultra-high purity. Radioimpurities within the crystals may potentially mimic dark matter signals and thus must be quantified, minimised where possible and distinguished from real events. Abundances of radionuclides <sup>129</sup>I and <sup>210</sup>Pb, which are dominant sources of radioimpurities in NaI(Tl) crystals, were measured using accelerator mass spectrometry at the Australian National University (ANU) and the Australian Nuclear Science and Technology Organisation (ANSTO). NaI powder chemically processed to AgI, and, for the first time, unprocessed NaI powder, were shown to be suitable as AMS targets. A consistent <sup>129</sup>I/<sup>127</sup>I ratio of (2.0<!--> <span><math><mo>±</mo></math></span> 0.3)<!--> <span><math><mo>×</mo></math></span> <!--> <!-->10<sup>−13</sup> was measured in three different commercially available NaI powders, one order of magnitude higher than the measured blank with (1.4<!--> <span><math><mo>±</mo></math></span> 0.3)<!--> <span><math><mo>×</mo></math></span> <!--> <!-->10<sup>−14</sup>. Therefore, it was concluded that the choice of NaI powder has a negligible influence on the <sup>129</sup>I contribution to low-background dark matter experiments. For <sup>210</sup>Pb, different Pb molecular ion species were assessed with PbO<span><math><msubsup><mrow></mrow><mrow><mn>2</mn></mrow><mrow><mo>−</mo></mrow></msubsup></math></span> being the preferred species and applied to investigate different lead oxide compounds for their suitability as Pb carriers. A <sup>210</sup>Pb/Pb isotopic ratio of (3.6 <span><math><mo>±</mo></math></span> <span><math><msubsup><mrow></mrow><mrow><mn>1</mn><mo>.</mo><mn>4</mn></mrow><mrow><mn>1</mn><mo>.</mo><mn>7</mn></mrow></msubsup></math></span>)<!--> <span><math><mo>×</mo></math></span> <!--> <!-->10<sup>−15</sup> was measured in Pb<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> powder. This met the required lower activity limit of <sup>210</sup>Pb when adding 1<!--> <!-->mg of stable lead into 1<!--> <!-->kg of NaI(Tl) powder with a desired maximum <sup>210</sup>Pb/Pb isotopic ratio of 1<!--> <span><math><mo>×</mo></math></span> <!--> <!-->10<sup>−14</sup>. These results indicate the suitability of the investigated Pb<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> as a potential carrier for incorporation with Pb extracted from NaI used for dark matter experiments.</div></div>","PeriodicalId":19380,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms","volume":"570 ","pages":"Article 165935"},"PeriodicalIF":1.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01Epub Date: 2025-11-10DOI: 10.1016/j.nimb.2025.165926
A.L.F. de Barros , C. Mejia , D.V. Doreste , A. Domaracka , P. Boduch , H. Rothard , E.F. da Silveira
Ices in interstellar and planetary environments are constantly altered by cosmic radiation. Using FTIR spectroscopy, we analyse radiation-induced changes in ices containing H2O, CO, CO2, and CH3OH, molecules abundant in the Solar System and interstellar medium. Molecular degradation is quantified by apparent cross-sections that scale with the electronic stopping power (Se). Literature data reveal a power-law dependence, σd ∝ Sen, influenced by thickness, sputtering yield, and radiochemical effects. This empirical relationship serves as a benchmark for assessing molecular stability and the interplay between sputtering and radiolysis, improving models of chemical evolution in astrophysical ices.
{"title":"Evaluation of the degradation cross-cection as stopping power dependence for pure and mixture molecular samples at cryogenic temperatures","authors":"A.L.F. de Barros , C. Mejia , D.V. Doreste , A. Domaracka , P. Boduch , H. Rothard , E.F. da Silveira","doi":"10.1016/j.nimb.2025.165926","DOIUrl":"10.1016/j.nimb.2025.165926","url":null,"abstract":"<div><div>Ices in interstellar and planetary environments are constantly altered by cosmic radiation. Using FTIR spectroscopy, we analyse radiation-induced changes in ices containing H<sub>2</sub>O, CO, CO<sub>2</sub>, and CH<sub>3</sub>OH,<!--> <!-->molecules abundant in the Solar System and interstellar medium. Molecular degradation is quantified by apparent cross-sections that scale with the electronic stopping power (S<sub>e</sub>). Literature data reveal a power-law dependence, σ<sub>d</sub> ∝ S<sub>e</sub><sup>n</sup>, influenced by thickness, sputtering yield, and radiochemical effects. This empirical relationship serves as a benchmark for assessing molecular stability and the interplay between sputtering and radiolysis, improving models of chemical evolution in astrophysical ices.</div></div>","PeriodicalId":19380,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms","volume":"570 ","pages":"Article 165926"},"PeriodicalIF":1.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01Epub Date: 2025-11-21DOI: 10.1016/j.nimb.2025.165951
A.M. Abdelmonem , M. Saleh , Wageeh Ramadan
An investigation of recycled polystyrene doped with 10 % of bagasse fiber impregnated with different weight percentages of SiO2 (0, 2.5, 5, 7.5 and 10 %) compositions against total and gamma ray. 137Cs and 60Co point sources were used with NaI(Tl) detector to evaluation the capabilities of investigated composites against gamma-ray. Moreover, a theoretical calculation for linear attenuation coefficient (LAC) for these composites by Phy-X/PSD software. Reasonable agreement between the experimental and theoretical parameters was observed. Additionally specific gamma ray constant and dose rate were derived over a wide range of gamma energies (0.015–15 MeV). SP4 and SP0 have the highest and lowest experimental LAC at 1.332 MeV gamma-rays, respectively, at 0.07120 and 0.06425 cm−1. The improvement percentages of empirical TGTF for SP1, SP2, SP3 and SP4 with respected to SP0 are 0.04998, 0.07497, 0.09995 and 0.27462 % at 0.5 cm thickness. An acceptable agreements between the experimental and calculated linear attenuation coefficient (µ) for gamma-ray were observed with relative differences not excesses 7.61 %. Using PAGEX software, the RKair, exposure buildup factor (EBF), and energy absorption buildup factor (EABF) were calculated. At 1.5 MeV gamma energy, the highest values of RKair are 1.073, 1.071, 1.070, 1.068, and 1.067 for SP0, SP1, SP2, and SP4, respectively.
{"title":"Assessment of sugarcane bagasse-recycled expanded polystyrene reinforced with nano-silica for gamma-rays shielding","authors":"A.M. Abdelmonem , M. Saleh , Wageeh Ramadan","doi":"10.1016/j.nimb.2025.165951","DOIUrl":"10.1016/j.nimb.2025.165951","url":null,"abstract":"<div><div>An investigation of recycled polystyrene doped with 10 % of bagasse fiber impregnated with different weight percentages of SiO<sub>2</sub> (0, 2.5, 5, 7.5 and 10 %) compositions against total and gamma ray. <sup>137</sup>Cs and <sup>60</sup>Co point sources were used with NaI(Tl) detector to evaluation the capabilities of investigated composites against gamma-ray. Moreover, a theoretical calculation for linear attenuation coefficient (LAC) for these composites by Phy-X/PSD software. Reasonable agreement between the experimental and theoretical parameters was observed. Additionally specific gamma ray constant and dose rate were derived over a wide range of gamma energies (0.015–15 MeV). SP4 and SP0 have the highest and lowest experimental LAC at 1.332 MeV gamma-rays, respectively, at 0.07120 and 0.06425 cm<sup>−1</sup>. The improvement percentages of empirical TGTF for SP1, SP2, SP3 and SP4 with respected to SP0 are 0.04998, 0.07497, 0.09995 and 0.27462 % at 0.5 cm thickness. An acceptable agreements between the experimental and calculated linear attenuation coefficient (µ) for gamma-ray were observed with relative differences not excesses 7.61 %. Using PAGEX software, the RK<sub>air</sub>, exposure buildup factor (EBF), and energy absorption buildup factor (EABF) were calculated. At 1.5 MeV gamma energy, the highest values of RK<sub>air</sub> are 1.073, 1.071, 1.070, 1.068, and 1.067 for SP0, SP1, SP2, and SP4, respectively.</div></div>","PeriodicalId":19380,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms","volume":"570 ","pages":"Article 165951"},"PeriodicalIF":1.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01Epub Date: 2025-11-01DOI: 10.1016/j.nimb.2025.165917
Brooke L. Cochran, Adib J. Samin
Mixed halide perovskites are candidates for solar cell applications in space environments. The non-perovskite δ-structure is known to coexist with the perovskite γ-structure and the kinetic barriers for the γ to δ transition are quite small. So, it is important to study this structure. In this work, we performed density functional theory (DFT)-based calculations on δ-CsPbI3 and δ-CsPb(I0.5Br0.5)3. First, no thermodynamic tendency for segregation was observed in the δ-CsPb(I0.5Br0.5)3 structure. The presence of Br in the vicinity lowered the iodine threshold displacement energy. Iodine vacancies were more stable than the Br vacancies. A strong dependence of the halide vacancies on the metallic atom coordination was observed. Finally, the highest migration energy barriers for the halide vacancies were observed for the cases where the hops were occurring between sites with the highest Pb-coordination. The results of this study may help apprise future efforts for realizing radiation-resistant perovskites for space.
{"title":"A study on the halide distribution, halide vacancies, and their diffusion in the δ-CsPb(I0.5Br0.5)3 mixed halide structure","authors":"Brooke L. Cochran, Adib J. Samin","doi":"10.1016/j.nimb.2025.165917","DOIUrl":"10.1016/j.nimb.2025.165917","url":null,"abstract":"<div><div>Mixed halide perovskites are candidates for solar cell applications in space environments. The non-perovskite δ-structure is known to coexist with the perovskite γ-structure and the kinetic barriers for the γ to δ transition are quite small. So, it is important to study this structure. In this work, we performed density functional theory (DFT)-based calculations on δ-CsPbI<sub>3</sub> and δ-CsPb(I<sub>0.5</sub>Br<sub>0.5</sub>)<sub>3</sub>. First, no thermodynamic tendency for segregation was observed in the δ-CsPb(I<sub>0.5</sub>Br<sub>0.5</sub>)<sub>3</sub> structure. The presence of Br in the vicinity lowered the iodine threshold displacement energy. Iodine vacancies were more stable than the Br vacancies. A strong dependence of the halide vacancies on the metallic atom coordination was observed. Finally, the highest migration energy barriers for the halide vacancies were observed for the cases where the hops were occurring between sites with the highest Pb-coordination. The results of this study may help apprise future efforts for realizing radiation-resistant perovskites for space.</div></div>","PeriodicalId":19380,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms","volume":"570 ","pages":"Article 165917"},"PeriodicalIF":1.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01Epub Date: 2025-10-31DOI: 10.1016/j.nimb.2025.165910
Fei Zhu , Junjie Tao , Yaowu Pei , Ziyi Wu , Tengyue Xiao , Ligang Song , Dong Wang , Xianfeng Ma
Molecular dynamics simulations were used to explore the impact of the direction of primary knock-on atom (200 keV) on the primary radiation damage in tungsten at various temperatures. The 〈110〉 PKA direction induces lower radiation damage, evident from the lower number of surviving Frenkel pairs, reduced interstitial/vacancy clustering fractions, lesser defects in large-sized clusters, and shorter dislocation lengths. The reduced damage in the 〈110〉 direction is attributed to its elevated probability of sub-cascades formation. The formation processes and mechanisms of different types of dislocations have been discussed. Mixed interstitial loops exhibit two distinct 〈100〉 fragment formation pathways. This study reveals three formation mechanisms for 〈100〉 interstitial loops: migrating 1/2〈111〉 loop interactions (primary), punch-out mechanism (secondary), and 1/2〈111〉→〈100〉 transformation through shear loop nucleation/propagation (tertiary). The 〈100〉 vacancy dislocations arise from the collapse of vacancy cluster. These findings provide critical insights into anisotropic radiation damage behavior and defect evolution mechanisms in tungsten.
{"title":"PKA direction on the primary radiation damage of tungsten by molecular dynamics simulations","authors":"Fei Zhu , Junjie Tao , Yaowu Pei , Ziyi Wu , Tengyue Xiao , Ligang Song , Dong Wang , Xianfeng Ma","doi":"10.1016/j.nimb.2025.165910","DOIUrl":"10.1016/j.nimb.2025.165910","url":null,"abstract":"<div><div>Molecular dynamics simulations were used to explore the impact of the direction of primary knock-on atom (200 keV) on the primary radiation damage in tungsten at various temperatures. The 〈110〉 PKA direction induces lower radiation damage, evident from the lower number of surviving Frenkel pairs, reduced interstitial/vacancy clustering fractions, lesser defects in large-sized clusters, and shorter dislocation lengths. The reduced damage in the 〈110〉 direction is attributed to its elevated probability of sub-cascades formation. The formation processes and mechanisms of different types of dislocations have been discussed. Mixed interstitial loops exhibit two distinct 〈100〉 fragment formation pathways. This study reveals three formation mechanisms for 〈100〉 interstitial loops: migrating 1/2〈111〉 loop interactions (primary), punch-out mechanism (secondary), and 1/2〈111〉→〈100〉 transformation through shear loop nucleation/propagation (tertiary). The 〈100〉 vacancy dislocations arise from the collapse of vacancy cluster. These findings provide critical insights into anisotropic radiation damage behavior and defect evolution mechanisms in tungsten.</div></div>","PeriodicalId":19380,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms","volume":"570 ","pages":"Article 165910"},"PeriodicalIF":1.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01Epub Date: 2025-11-23DOI: 10.1016/j.nimb.2025.165955
Yun Li , Shunchang Cheng , Wuxian Zeng , Yao Ma , Mingmin Huang , Min Gong , Zhimei Yang
The impact of 1.7 MeV electron irradiation on the silicon-based reach-through APD (Si-RAPD) was investigated using deep level transient spectroscopy (DLTS), capacitance-voltage (C-V) and current-voltage (I-V) measurements. DLTS results demonstrate that electron irradiation introduces stable V2 (0/-) defects, which act as recombination centers within the device. As the irradiation dose increases, both doping concentration (ND) and carrier mobility (μ) decrease, while the concentration of V2 (0/-) defects, the higher forward voltage (VF) and resistance (R) exhibit obviously positive correlations with electron irradiation dose. Prolonged irradiation raises the internal temperature of the Si-RAPD, potentially causing partial in-situ annealing of extended defects during the irradiation process. Following annealing at 200 °C for 10 min, the intensity of the P1 peak decreases and its asymmetry becomes more pronounced, indicating that the irradiation-induced defects may undergo transformation, potentially forming new defect states that further influence the electrical properties of the Si-RAPD. Ultimately, electron irradiation leads to a substantial increase in the dark current of Si-RAPDs, indicating a degradation in device performance. Consequently, these results provide valuable insights into the degradation mechanism of Si-RAPD under electron irradiation.
{"title":"The degradation mechanism of the reach-through silicon avalanche photodiode by 1.7 MeV electron irradiation","authors":"Yun Li , Shunchang Cheng , Wuxian Zeng , Yao Ma , Mingmin Huang , Min Gong , Zhimei Yang","doi":"10.1016/j.nimb.2025.165955","DOIUrl":"10.1016/j.nimb.2025.165955","url":null,"abstract":"<div><div>The impact of 1.7 MeV electron irradiation on the silicon-based reach-through APD (Si-RAPD) was investigated using deep level transient spectroscopy (DLTS), capacitance-voltage (C-V) and current-voltage (I-V) measurements. DLTS results demonstrate that electron irradiation introduces stable <em>V<sub>2</sub> (0/-)</em> defects, which act as recombination centers within the device. As the irradiation dose increases, both doping concentration (<em>N<sub>D</sub></em>) and carrier mobility (<em>μ</em>) decrease, while the concentration of <em>V<sub>2</sub> (0/-)</em> defects, the higher forward voltage <em>(V<sub>F</sub>)</em> and resistance (<em>R</em>) exhibit obviously positive correlations with electron irradiation dose. Prolonged irradiation raises the internal temperature of the Si-RAPD, potentially causing partial in-situ annealing of extended defects during the irradiation process. Following annealing at 200 °C for 10 min, the intensity of the P1 peak decreases and its asymmetry becomes more pronounced, indicating that the irradiation-induced defects may undergo transformation, potentially forming new defect states that further influence the electrical properties of the Si-RAPD. Ultimately, electron irradiation leads to a substantial increase in the dark current of Si-RAPDs, indicating a degradation in device performance. Consequently, these results provide valuable insights into the degradation mechanism of Si-RAPD under electron irradiation.</div></div>","PeriodicalId":19380,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms","volume":"570 ","pages":"Article 165955"},"PeriodicalIF":1.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145620824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-01-01Epub Date: 2025-11-25DOI: 10.1016/j.nimb.2025.165952
S. Shanmuga Sundari , S. Karthika , A. Durairajan , K. Asokan , R.C. Meena
Barium stannate ceramics (BaSnO3) was synthesized using high-temperature mixed-oxide technique. The precursors barium carbonate (BaCO3) and tin oxide (SnO2) were calcinated at 500°C for 6 h and sintered at 1400°C for 4 h and made into pellets. They were irradiated with Lithium (Li+) and Tungsten (W+) ion of 100 MeV energy at a fluence of 1 × 1013 ions/cm2. XRD reveals crystalline nature and cubic structure of the prepared and irradiated BaSnO3 ceramics. The morphology of both as prepared and irradiated ceramics were analysed using SEM images and the ceramics possess hexagonal cubic structure. To analyze the electrical properties, dielectric spectroscopy for the prepared BaSnO3 ceramics and ion irradiated BaSnO3 ceramics were recorded from room temperature to 400 °C in a frequency range of 1 kHz to 2 MHz for every 5 degrees. A. C. conduction mechanism of the ceramics was recorded and the activation energy of the sample before and after ion irradiation was calculated using Arrhenius plot. The activation energy was found to decrease as frequency increases for pristine and irradiated ceramics.
{"title":"Li+ and W+ ion irradiation induced changes on the electrical properties of BaSnO3 ceramics","authors":"S. Shanmuga Sundari , S. Karthika , A. Durairajan , K. Asokan , R.C. Meena","doi":"10.1016/j.nimb.2025.165952","DOIUrl":"10.1016/j.nimb.2025.165952","url":null,"abstract":"<div><div>Barium stannate ceramics (BaSnO<sub>3</sub>) was synthesized using high-temperature mixed-oxide technique. The precursors barium carbonate (BaCO<sub>3</sub>) and tin oxide (SnO<sub>2</sub>) were calcinated at 500°C for 6 h and sintered at 1400°C for 4 h and made into pellets. They were irradiated with Lithium (Li<sup>+</sup>) and Tungsten (W<sup>+</sup>) ion of 100 MeV energy at a fluence of 1 × 10<sup>13</sup> ions/cm<sup>2</sup>. XRD reveals crystalline nature and cubic structure of the prepared and irradiated BaSnO<sub>3</sub> ceramics. The morphology of both as prepared and irradiated ceramics were analysed using SEM images and the ceramics possess hexagonal cubic structure. To analyze the electrical properties, dielectric spectroscopy for the prepared BaSnO<sub>3</sub> ceramics and ion irradiated BaSnO<sub>3</sub> ceramics were recorded from room temperature to 400<!--> <!-->°C in a frequency range of 1 kHz to 2 MHz for every 5 degrees. A. C. conduction mechanism of the ceramics was recorded and the activation energy of the sample before and after ion irradiation was calculated using Arrhenius plot. The activation energy was found to decrease as frequency increases for pristine and irradiated ceramics.</div></div>","PeriodicalId":19380,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms","volume":"570 ","pages":"Article 165952"},"PeriodicalIF":1.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145620828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
A transmission-type brightness-enhancement system with a simple and compact design has been developed for the slow positron beamline at Kyoto University Research Reactor (KUR). This system allows for rapid switching between primary and brightness-enhanced beams. The continuity of guiding magnetic fields along the beamline is crucial, as it affects longitudinal velocity spreads and beam sizes. A magnetic lens has been designed for the brightness-enhancement system to maintain continuous magnetic fields while enabling the transportation of the primary beam without brightness enhancement. A crystalline 150-nm-thick Ni film was utilized as the re-moderator material. The newly developed brightness-enhancement system demonstrated brightness improvements approaching 10 times, depending on the acceleration voltages within the range of 5.0–6.5 kV. In addition, the energy spread of the beam was reduced to approximately one-tenth of its initial value. The primary beam was successfully transported without brightness enhancement, and positron annihilation lifetime spectroscopy measurements were conducted using the brightness-enhanced beams.
{"title":"Transmission-type brightness-enhancement system for reactor-based slow positron beamline","authors":"Yoshihiro Kuzuya , Nagayasu Oshima , Atsushi Yabuuchi , Atsushi Kinomura","doi":"10.1016/j.nimb.2025.165946","DOIUrl":"10.1016/j.nimb.2025.165946","url":null,"abstract":"<div><div>A transmission-type brightness-enhancement system with a simple and compact design has been developed for the slow positron beamline at Kyoto University Research Reactor (KUR). This system allows for rapid switching between primary and brightness-enhanced beams. The continuity of guiding magnetic fields along the beamline is crucial, as it affects longitudinal velocity spreads and beam sizes. A magnetic lens has been designed for the brightness-enhancement system to maintain continuous magnetic fields while enabling the transportation of the primary beam without brightness enhancement. A crystalline 150-nm-thick Ni film was utilized as the re-moderator material. The newly developed brightness-enhancement system demonstrated brightness improvements approaching 10 times, depending on the acceleration voltages within the range of 5.0–6.5 kV. In addition, the energy spread of the beam was reduced to approximately one-tenth of its initial value. The primary beam was successfully transported without brightness enhancement, and positron annihilation lifetime spectroscopy measurements were conducted using the brightness-enhanced beams.</div></div>","PeriodicalId":19380,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms","volume":"570 ","pages":"Article 165946"},"PeriodicalIF":1.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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