Pub Date : 2026-01-14DOI: 10.1016/j.nima.2026.171296
Huaiyong Bai, Hang Li, Lisheng Yang, Hengrui Zhang, Ji Wen, Chengguo Pang, Binyuan Xia, Ming Su, Fan Gao, Chenguang Li, Xiaodong Wang
Fast neutron imaging is a powerful measurement technique, particularly suitable for large-sized samples containing both light and heavy materials. However, it is severely affected by background events, leading to compromised image quality. To achieve substantially improved results, a novel fast neutron imaging detector is proposed, which mainly consists of crisscrossed wavelength-shifting fibers, the composite mixture of YAP(Ce) scintillation powder and polypropylene powder, and SiPM arrays. The detector offers several advantages including excellent spatial resolution, a large sensitive area, and high detection efficiency. Furthermore, another key merit lies in its temporal response, which is expected to be no more than 1 ns. This enables the application of time-of-flight technology for identifying directly transmitted neutron events, thereby effectively suppressing the corresponding background events.
{"title":"Design of a novel fast neutron imaging detector with excellent spatial resolution, fast temporal response, large sensitive area, and high detection efficiency","authors":"Huaiyong Bai, Hang Li, Lisheng Yang, Hengrui Zhang, Ji Wen, Chengguo Pang, Binyuan Xia, Ming Su, Fan Gao, Chenguang Li, Xiaodong Wang","doi":"10.1016/j.nima.2026.171296","DOIUrl":"10.1016/j.nima.2026.171296","url":null,"abstract":"<div><div>Fast neutron imaging is a powerful measurement technique, particularly suitable for large-sized samples containing both light and heavy materials. However, it is severely affected by background events, leading to compromised image quality. To achieve substantially improved results, a novel fast neutron imaging detector is proposed, which mainly consists of crisscrossed wavelength-shifting fibers, the composite mixture of YAP(Ce) scintillation powder and polypropylene powder, and SiPM arrays. The detector offers several advantages including excellent spatial resolution, a large sensitive area, and high detection efficiency. Furthermore, another key merit lies in its temporal response, which is expected to be no more than 1 ns. This enables the application of time-of-flight technology for identifying directly transmitted neutron events, thereby effectively suppressing the corresponding background events.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171296"},"PeriodicalIF":1.4,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024230","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 : 2026-01-14DOI: 10.1016/j.nima.2026.171277
Shimin Jiang , Shengjin Liu , Zhijun Lu , Xingguang Liu , Xiao Li , Renjun Yang
This paper addresses the issue in C-band photocathode radio frequency (RF) guns where the presence of significant multipole field components in the accelerating field, restricts the improvement of beam quality. A strategy of optimizing the multipole field components in the RF structure is adopted to alleviate this problem, and a detailed analysis is conducted on the matching performance of the multipole field components generated by the pick-ups and coaxial waveguide couplers respectively. Simulation results show that after rotating the two pick-ups by 30°, the influences of the multipole field components generated by the pick-ups and couplers at the beam position can cancel each other out, thereby minimizing the impact of the multipole field components on the beam at the target position. This optimized scheme has been applied to the final gun design. After analyzing the effects of the solenoid and correction coils on the beam, the transverse emittance difference caused by the multipole field components at the target position is reduced to below 0.01 mm mrad. These research results provide a new method for the optimization of multipole field components in RF guns.
本文研究了c波段光电阴极射频炮中加速场中存在显著的多极场分量，制约了束流质量提高的问题。采用优化射频结构中多极场分量的策略来缓解这一问题，并分别对拾音器和同轴波导耦合器产生的多极场分量的匹配性能进行了详细分析。仿真结果表明，将两个拾取器旋转30°后，拾取器和耦合器在光束位置产生的多极场分量的影响可以相互抵消，从而使目标位置的多极场分量对光束的影响最小化。该优化方案已应用于火炮的最终设计。通过分析电磁线圈和校正线圈对波束的影响，将目标位置多极场分量引起的横向发射度差减小到0.01 mm mrad以下。这些研究结果为射频炮中多极场元件的优化设计提供了一种新的方法。
{"title":"Analysis of multipole field reduction in C-band photocathode RF gun","authors":"Shimin Jiang , Shengjin Liu , Zhijun Lu , Xingguang Liu , Xiao Li , Renjun Yang","doi":"10.1016/j.nima.2026.171277","DOIUrl":"10.1016/j.nima.2026.171277","url":null,"abstract":"<div><div>This paper addresses the issue in C-band photocathode radio frequency (RF) guns where the presence of significant multipole field components in the accelerating field, restricts the improvement of beam quality. A strategy of optimizing the multipole field components in the RF structure is adopted to alleviate this problem, and a detailed analysis is conducted on the matching performance of the multipole field components generated by the pick-ups and coaxial waveguide couplers respectively. Simulation results show that after rotating the two pick-ups by 30°, the influences of the multipole field components generated by the pick-ups and couplers at the beam position can cancel each other out, thereby minimizing the impact of the multipole field components on the beam at the target position. This optimized scheme has been applied to the final gun design. After analyzing the effects of the solenoid and correction coils on the beam, the transverse emittance difference caused by the multipole field components at the target position is reduced to below 0.01 mm mrad. These research results provide a new method for the optimization of multipole field components in RF guns.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171277"},"PeriodicalIF":1.4,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024154","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 : 2026-01-14DOI: 10.1016/j.nima.2026.171281
R. Mondal Saha , K. Banerjee , N. Gayathri , Saif Ahmad Khan , S. Dalal , R. Shil , P. Pant , S.R. Singh , T. Bar , K.S. Golda
Lithium, being an alkali metal, is highly susceptible to oxidation, making the target preparation particularly challenging. To overcome this limitation, various lithium compounds-lithium carbonate (LiCO), lithium fluoride (LiF), and lithium hydroxide monohydrate (HLiO) were employed for target fabrication using sedimentation and vapour deposition technique. The stability of these compound-based targets was compared with that of metallic lithium target by evaluating their longevity upon exposure to the atmosphere. Morphological and elemental analyses were performed on the fabricated targets and the raw powder materials to examine structural changes and purity variations during fabrication. These targets were subsequently irradiated with proton beams to study the resulting neutron energy spectra. Furthermore, Monte Carlo simulations were carried out to estimate the spatial and energy distributions of proton beams transmitted through the different targets. The results indicate that lithium compounds with higher densities lead to greater energy and spatial broadening of the transmitted beams. Analysis also indicates a critical density of 2.2 g/cm, beyond which further increases in spatial and energy spread become minimal.
{"title":"Challenges and methods in fabricating solid lithium-compound targets","authors":"R. Mondal Saha , K. Banerjee , N. Gayathri , Saif Ahmad Khan , S. Dalal , R. Shil , P. Pant , S.R. Singh , T. Bar , K.S. Golda","doi":"10.1016/j.nima.2026.171281","DOIUrl":"10.1016/j.nima.2026.171281","url":null,"abstract":"<div><div>Lithium, being an alkali metal, is highly susceptible to oxidation, making the target preparation particularly challenging. To overcome this limitation, various lithium compounds-lithium carbonate (Li<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>CO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>), lithium fluoride (LiF), and lithium hydroxide monohydrate (H<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>LiO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>) were employed for target fabrication using sedimentation and vapour deposition technique. The stability of these compound-based targets was compared with that of metallic lithium target by evaluating their longevity upon exposure to the atmosphere. Morphological and elemental analyses were performed on the fabricated targets and the raw powder materials to examine structural changes and purity variations during fabrication. These targets were subsequently irradiated with proton beams to study the resulting neutron energy spectra. Furthermore, Monte Carlo simulations were carried out to estimate the spatial and energy distributions of proton beams transmitted through the different targets. The results indicate that lithium compounds with higher densities lead to greater energy and spatial broadening of the transmitted beams. Analysis also indicates a critical density of <span><math><mo>≈</mo></math></span>2.2 g/cm<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span>, beyond which further increases in spatial and energy spread become minimal.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171281"},"PeriodicalIF":1.4,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024153","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 : 2026-01-14DOI: 10.1016/j.nima.2026.171295
B. Davids , N.E. Esker , J. Jaeyoung , Y.K. Kim , K. Pak , M. Williams
The mean transmission efficiency of the EMMA recoil mass spectrometer at TRIUMF has been measured with 6 different angular apertures at 17 kinetic energy/charge deviations with respect to the central, reference trajectory. Measurements performed using a 148Gd source installed at the target position of the spectrometer are compared to ion-optical calculations and Monte Carlo simulations. The transmission efficiency as a function of angle and kinetic energy/charge is described empirically using piecewise Gaussian functions whose parameters are fit to the data.
{"title":"Transmission efficiency of the recoil mass spectrometer EMMA at TRIUMF","authors":"B. Davids , N.E. Esker , J. Jaeyoung , Y.K. Kim , K. Pak , M. Williams","doi":"10.1016/j.nima.2026.171295","DOIUrl":"10.1016/j.nima.2026.171295","url":null,"abstract":"<div><div>The mean transmission efficiency of the EMMA recoil mass spectrometer at TRIUMF has been measured with 6 different angular apertures at 17 kinetic energy/charge deviations with respect to the central, reference trajectory. Measurements performed using a <sup>148</sup>Gd <span><math><mi>α</mi></math></span> source installed at the target position of the spectrometer are compared to ion-optical calculations and Monte Carlo simulations. The transmission efficiency as a function of angle and kinetic energy/charge is described empirically using piecewise Gaussian functions whose parameters are fit to the data.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171295"},"PeriodicalIF":1.4,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024233","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 : 2026-01-10DOI: 10.1016/j.nima.2026.171279
Simon Spannagel , Stephan Lachnit , Hanno Perrey , Justus Braach , Lene Kristian Bryngemark , Erika Garutti , Adrian Herkert , Finn King , Christoph Krieger , David Leppla-Weber , Linus Ros , Sara Ruiz Daza , Murtaza Safdari , Luis G. Sarmiento , Annika Vauth , Håkan Wennlöf
The operation of instruments and detectors in laboratory or beamline environments presents a complex challenge, requiring stable operation of multiple concurrent devices, often controlled by separate hardware and software solutions. These environments frequently undergo modifications, such as the inclusion of different auxiliary devices depending on the experiment or facility, adding further complexity. The successful management of such dynamic configurations demands a flexible and robust system capable of controlling data acquisition, monitoring experimental setups, enabling seamless reconfiguration, and integrating new devices with limited effort.
This paper presents Constellation, a flexible and network-distributed control and data acquisition software framework tailored to laboratory and beamline environments, that addresses the limitations of existing solutions. The framework is designed with a focus on extensibility, providing a streamlined interface for instrument integration. It supports efficient system setup via network discovery mechanisms, promotes stability through autonomous operational features, and provides comprehensive documentation and supporting tools for operators and application developers such as controllers and logging interfaces.
At the core of the architectural design is the autonomy of the individual components, called satellites, which can make independent decisions about their operation and communicate these decisions to other components. This paper introduces the design principles and framework architecture of Constellation, presents the available graphical user interfaces, shares insights from initial successful deployments, and provides an outlook on future developments and applications.
{"title":"Constellation: The autonomous control and data acquisition system for dynamic experimental setups","authors":"Simon Spannagel , Stephan Lachnit , Hanno Perrey , Justus Braach , Lene Kristian Bryngemark , Erika Garutti , Adrian Herkert , Finn King , Christoph Krieger , David Leppla-Weber , Linus Ros , Sara Ruiz Daza , Murtaza Safdari , Luis G. Sarmiento , Annika Vauth , Håkan Wennlöf","doi":"10.1016/j.nima.2026.171279","DOIUrl":"10.1016/j.nima.2026.171279","url":null,"abstract":"<div><div>The operation of instruments and detectors in laboratory or beamline environments presents a complex challenge, requiring stable operation of multiple concurrent devices, often controlled by separate hardware and software solutions. These environments frequently undergo modifications, such as the inclusion of different auxiliary devices depending on the experiment or facility, adding further complexity. The successful management of such dynamic configurations demands a flexible and robust system capable of controlling data acquisition, monitoring experimental setups, enabling seamless reconfiguration, and integrating new devices with limited effort.</div><div>This paper presents Constellation, a flexible and network-distributed control and data acquisition software framework tailored to laboratory and beamline environments, that addresses the limitations of existing solutions. The framework is designed with a focus on extensibility, providing a streamlined interface for instrument integration. It supports efficient system setup via network discovery mechanisms, promotes stability through autonomous operational features, and provides comprehensive documentation and supporting tools for operators and application developers such as controllers and logging interfaces.</div><div>At the core of the architectural design is the autonomy of the individual components, called <em>satellites</em>, which can make independent decisions about their operation and communicate these decisions to other components. This paper introduces the design principles and framework architecture of Constellation, presents the available graphical user interfaces, shares insights from initial successful deployments, and provides an outlook on future developments and applications.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171279"},"PeriodicalIF":1.4,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980298","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 : 2026-01-09DOI: 10.1016/j.nima.2026.171283
Hanqiu Jiang , Jiajun Zhong , Changlong Chen , Junrong Zhang , Rong Du
Data reduction plays a critical role in the commissioning of the time-of-flight Small-angle Neutron Scattering (SANS) instrument at the China Spallation Neutron Source (CSNS). While the generalized SANS data reduction protocols and software have been well-established, the specific data architecture and the diverse user community of this instrument create unique need for a tailored data reduction system.
A novel software package sansRZ, also as an integral component of the RZera project, has been developed for the CSNS SANS instrument. The fundamental calculation algorithms are adopted from the robust, community-validated Mantid framework. A modular, Python based extension was built around this core to provide rapid data handling, self-diagnostic capability and better graphical user interface (GUI). An data validation module and the comprehensive logging capabilities have been developed within the Python structure to help users identify potential data issues early in the data reduction process. This article presents an overview of the software architecture as well as the main features and capabilities of the software.
{"title":"sansRZ: A python-based data reduction tool for the time-of-flight SANS instrument at CSNS","authors":"Hanqiu Jiang , Jiajun Zhong , Changlong Chen , Junrong Zhang , Rong Du","doi":"10.1016/j.nima.2026.171283","DOIUrl":"10.1016/j.nima.2026.171283","url":null,"abstract":"<div><div>Data reduction plays a critical role in the commissioning of the time-of-flight Small-angle Neutron Scattering (SANS) instrument at the China Spallation Neutron Source (CSNS). While the generalized SANS data reduction protocols and software have been well-established, the specific data architecture and the diverse user community of this instrument create unique need for a tailored data reduction system.</div><div>A novel software package <strong>sansRZ</strong>, also as an integral component of the <strong>RZera</strong> project, has been developed for the CSNS SANS instrument. The fundamental calculation algorithms are adopted from the robust, community-validated Mantid framework. A modular, Python based extension was built around this core to provide rapid data handling, self-diagnostic capability and better graphical user interface (GUI). An data validation module and the comprehensive logging capabilities have been developed within the Python structure to help users identify potential data issues early in the data reduction process. This article presents an overview of the software architecture as well as the main features and capabilities of the software.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171283"},"PeriodicalIF":1.4,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980300","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}
Superconducting linear accelerators in Accelerator-Driven Subcritical Systems (ADS) demand very high availability, as unplanned beam trips can endanger the spallation target and reactor. To address reliability and protection needs at the China Initiative Accelerator-Driven Subcritical System (CiADS) facility, we design and validate a System-on-Chip (SoC)-based dual-redundant master controller for magnet power supplies. The controller integrates: (i) an FPGA-resident finite-state-machine (FSM) fast-protection core for superconducting and normal-conducting magnets; (ii) a dual-master hot-standby mechanism; (iii) N+1 current-sharing with module-failure compensation; and (iv) a triggered fault-snapshot pipeline with EPICS integration. Experiments on the HIAF-iLinac testbed show failover of 500 ± 20 ms, seamless switchover with no output disturbance, <30 % CAN-bus utilization, and fault snapshots that match oscilloscope captures. These results indicate that the SoC-based controller meets CiADS protection and redundancy requirements while improving determinism, maintainability, and long-term reliability over conventional PLC/PC architectures, providing a reusable reference design for future megawatt-scale ADS facilities.
{"title":"Functional design and implementation of the CiADS power supply master controller based on System-on-Chip","authors":"Wenqi Lyu , Yuan He , Ximeng Chen , QingQing Linghu , Zhongzu Zhou , Zhijun Wang , Jiang Zhao , Detai Zhou , Zongheng Xue","doi":"10.1016/j.nima.2026.171276","DOIUrl":"10.1016/j.nima.2026.171276","url":null,"abstract":"<div><div>Superconducting linear accelerators in Accelerator-Driven Subcritical Systems (ADS) demand very high availability, as unplanned beam trips can endanger the spallation target and reactor. To address reliability and protection needs at the China Initiative Accelerator-Driven Subcritical System (CiADS) facility, we design and validate a System-on-Chip (SoC)-based dual-redundant master controller for magnet power supplies. The controller integrates: (i) an FPGA-resident finite-state-machine (FSM) fast-protection core for superconducting and normal-conducting magnets; (ii) a dual-master hot-standby mechanism; (iii) <em>N</em>+1 current-sharing with module-failure compensation; and (iv) a triggered fault-snapshot pipeline with EPICS integration. Experiments on the HIAF-iLinac testbed show failover of 500 ± 20 ms, seamless switchover with no output disturbance, <30 % CAN-bus utilization, and fault snapshots that match oscilloscope captures. These results indicate that the SoC-based controller meets CiADS protection and redundancy requirements while improving determinism, maintainability, and long-term reliability over conventional PLC/PC architectures, providing a reusable reference design for future megawatt-scale ADS facilities.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171276"},"PeriodicalIF":1.4,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980299","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 : 2026-01-08DOI: 10.1016/j.nima.2026.171280
Marcus A.P. Miljak , Pramod Koshy , Joel N. O'Dwyer
Scientists working with XRD have limited tools to model intricacies in XRD experiments. Conventional Bragg-Brentano style powder diffractometers have robust in-built software which allow users to simulate powder XRD diffractograms. However, these programs can only account for so many modifications to powder XRD experiments. Thus, there is no all-encompassing software that allows a user to simulate a powder XRD diffractogram from an arbitrary experimental geometry, while also being able to account for all necessary X-ray physics and crystallographic information.
A modification to Geant4 Penelope Rayleigh scattering model has been performed that allows a user to simulate physically accurate coherent elastic scattering (Bragg scattering) from a powdered crystal material. This will enable scientists to simulate XRD experiments, with any geometry, as long as it can be constructed in Geant4 while also accounting for all necessary physics.
To showcase the modification, two Bragg-Brentano style diffractometers (Empyrean I and MiniFlex) have been constructed in Geant4 and were used to produce a simulated diffractogram. The simulations were undertaken with custom generated scattering form factors that account for inherent diffraction peak broadening. These results are compared to experimentally obtained diffractograms, with the analysis revealing a good match. Thus, this showcases the potential for the model to be used in different diverse XRD experiment simulations.
{"title":"Powder X-ray diffraction implementation in Geant4","authors":"Marcus A.P. Miljak , Pramod Koshy , Joel N. O'Dwyer","doi":"10.1016/j.nima.2026.171280","DOIUrl":"10.1016/j.nima.2026.171280","url":null,"abstract":"<div><div>Scientists working with XRD have limited tools to model intricacies in XRD experiments. Conventional Bragg-Brentano style powder diffractometers have robust in-built software which allow users to simulate powder XRD diffractograms. However, these programs can only account for so many modifications to powder XRD experiments. Thus, there is no all-encompassing software that allows a user to simulate a powder XRD diffractogram from an arbitrary experimental geometry, while also being able to account for all necessary X-ray physics and crystallographic information.</div><div>A modification to Geant4 Penelope Rayleigh scattering model has been performed that allows a user to simulate physically accurate coherent elastic scattering (Bragg scattering) from a powdered crystal material. This will enable scientists to simulate XRD experiments, with any geometry, as long as it can be constructed in Geant4 while also accounting for all necessary physics.</div><div>To showcase the modification, two Bragg-Brentano style diffractometers (Empyrean I and MiniFlex) have been constructed in Geant4 and were used to produce a simulated diffractogram. The simulations were undertaken with custom generated scattering form factors that account for inherent diffraction peak broadening. These results are compared to experimentally obtained diffractograms, with the analysis revealing a good match. Thus, this showcases the potential for the model to be used in different diverse XRD experiment simulations.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171280"},"PeriodicalIF":1.4,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980301","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 : 2026-01-08DOI: 10.1016/j.nima.2026.171278
Xuanqi Zhang , Yulan Li , Zhi Zhang , Yang Tian , Zhijun Chi , Hao Ding , Hongze Zhang , Jin Lin , Yingchao Du , Chuanxiang Tang
The Very Compact Inverse Compton Scattering Gamma-ray Source (VIGAS) is a gamma-ray facility under construction at Tsinghua University. It has the ability to produce more than quasi-monoenergetic gamma photons per pulse within 10 ps. Due to ultra-short pulse length, conventional detectors and methods cannot directly measure the energy spectrum of the VIGAS. In this study, we employ the Compton scattering method to reduce the photon flux and collect the scattered photons in a specific direction using high-purity germanium (HPGe) detectors. The central energy and energy spread of the incident gamma rays can be determined by analyzing the spectrum of the scattered photons. To correct for the Doppler broadening effect during the Compton scattering process, the error transfer formula method is developed. Monte Carlo simulations show that the energy spectrum of the VIGAS can be reconstructed accurately by error transfer formula method, with a central energy accuracy better than 0.1% and energy spread accuracy better than 3%. A proof-of-principle experiment conducted at the Shanghai Laser Electron Gamma Source (SLEGS) validates the feasibility of the Compton scattering-based reconstruction method for energy spectrum measurements.
{"title":"A Compton scattering-based energy spectrum measurement method for high flux gamma-ray of VIGAS facility","authors":"Xuanqi Zhang , Yulan Li , Zhi Zhang , Yang Tian , Zhijun Chi , Hao Ding , Hongze Zhang , Jin Lin , Yingchao Du , Chuanxiang Tang","doi":"10.1016/j.nima.2026.171278","DOIUrl":"10.1016/j.nima.2026.171278","url":null,"abstract":"<div><div>The Very Compact Inverse Compton Scattering Gamma-ray Source (VIGAS) is a gamma-ray facility under construction at Tsinghua University. It has the ability to produce more than <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>6</mn></mrow></msup></mrow></math></span> quasi-monoenergetic gamma photons per pulse within 10 ps. Due to ultra-short pulse length, conventional detectors and methods cannot directly measure the energy spectrum of the VIGAS. In this study, we employ the Compton scattering method to reduce the photon flux and collect the scattered photons in a specific direction using high-purity germanium (HPGe) detectors. The central energy and energy spread of the incident gamma rays can be determined by analyzing the spectrum of the scattered photons. To correct for the Doppler broadening effect during the Compton scattering process, the error transfer formula method is developed. Monte Carlo simulations show that the energy spectrum of the VIGAS can be reconstructed accurately by error transfer formula method, with a central energy accuracy better than 0.1% and energy spread accuracy better than 3%. A proof-of-principle experiment conducted at the Shanghai Laser Electron Gamma Source (SLEGS) validates the feasibility of the Compton scattering-based reconstruction method for energy spectrum measurements.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171278"},"PeriodicalIF":1.4,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929141","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 : 2026-01-07DOI: 10.1016/j.nima.2025.171245
H. Eick , E. Aktan , P. Brand , T. Burg , M. Cerchez , C. Mannweiler , S. Vestrick , O. Willi , A. Khoukaz
Precise knowledge of cluster-jet target beam properties like the cluster size and speed is essential for the planning, execution, and analysis of hadron physics and high-power laser experiments. Here, we present results of size distributions obtained from shadowgraphy measurements of hydrogen clusters at a state-of-the-art cluster-jet target generator. The cluster-jets were generated by expanding cryogenic hydrogen in a de Laval nozzle at various stagnation conditions in the liquid state. Near the nozzle exit, cluster sizes are found to be well below 10 m and little dependence of the cluster diameter on stagnation conditions is observed. The investigated size distributions as well as the abundance allow the estimation of the granularity of the cluster beam at possible interaction points for experiments with electron, hadron, or laser beams.
{"title":"Determination of hydrogen cluster size distributions of a cluster-jet target using shadowgraphy","authors":"H. Eick , E. Aktan , P. Brand , T. Burg , M. Cerchez , C. Mannweiler , S. Vestrick , O. Willi , A. Khoukaz","doi":"10.1016/j.nima.2025.171245","DOIUrl":"10.1016/j.nima.2025.171245","url":null,"abstract":"<div><div>Precise knowledge of cluster-jet target beam properties like the cluster size and speed is essential for the planning, execution, and analysis of hadron physics and high-power laser experiments. Here, we present results of size distributions obtained from shadowgraphy measurements of hydrogen clusters at a state-of-the-art cluster-jet target generator. The cluster-jets were generated by expanding cryogenic hydrogen in a de Laval nozzle at various stagnation conditions in the liquid state. Near the nozzle exit, cluster sizes are found to be well below 10 <span><math><mi>μ</mi></math></span>m and little dependence of the cluster diameter on stagnation conditions is observed. The investigated size distributions as well as the abundance allow the estimation of the granularity of the cluster beam at possible interaction points for experiments with electron, hadron, or laser beams.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171245"},"PeriodicalIF":1.4,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929142","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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