Pub Date : 2026-01-30DOI: 10.1016/j.nima.2026.171338
W.F. Rogers , A.N. Kuchera , T. Awal , T. Baumann , C. Capuano , D. Chrisman , M. Devlin , D. Flores Madrid , J. Glaze , O. Guarinello , P. Gueye , J. Hallett , B. Hassan , K.J. Kelly , O. Lucas , A. Maki , S. Mosby , A. Munroe , T. Redpath , A. Robinson , S. Winner
Plastic scintillator detectors are widely used in nuclear physics experiments and applications. The interpretation of the data often relies on simulation to understand the performance of the detectors and to assist with the analysis of decay energies and widths of neutron-rich nuclei. A neutron scattering experiment was conducted at the Los Alamos Neutron Science Center (LANSCE) to study neutrons scattering from H and C nuclei in plastic scintillators for neutrons with energy 20 to 400 MeV. The detector array consisted of a single detector bar serving as target, and a 45° ramp of detectors 2 m downstream. Results for three interaction observables, including scintillation light detected, kinetic energy distribution following the first scatter, and scattering angle, were compared with predictions from two Geant4-based simulation packages, referred to here as G4-Physics and MENATE_R. Agreement between simulation and data was best for events consisting of a single hit, and poorer for events consisting of two hits.
{"title":"Testing interaction simulations with 20–400 MeV neutron scattering data from plastic scintillators","authors":"W.F. Rogers , A.N. Kuchera , T. Awal , T. Baumann , C. Capuano , D. Chrisman , M. Devlin , D. Flores Madrid , J. Glaze , O. Guarinello , P. Gueye , J. Hallett , B. Hassan , K.J. Kelly , O. Lucas , A. Maki , S. Mosby , A. Munroe , T. Redpath , A. Robinson , S. Winner","doi":"10.1016/j.nima.2026.171338","DOIUrl":"10.1016/j.nima.2026.171338","url":null,"abstract":"<div><div>Plastic scintillator detectors are widely used in nuclear physics experiments and applications. The interpretation of the data often relies on simulation to understand the performance of the detectors and to assist with the analysis of decay energies and widths of neutron-rich nuclei. A neutron scattering experiment was conducted at the Los Alamos Neutron Science Center (LANSCE) to study neutrons scattering from H and C nuclei in plastic scintillators for neutrons with energy 20 to 400 MeV. The detector array consisted of a single detector bar serving as target, and a 45° ramp of detectors 2 m downstream. Results for three interaction observables, including scintillation light detected, kinetic energy distribution following the first scatter, and scattering angle, were compared with predictions from two Geant4-based simulation packages, referred to here as G4-Physics and MENATE_R. Agreement between simulation and data was best for events consisting of a single hit, and poorer for events consisting of two hits.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171338"},"PeriodicalIF":1.4,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081865","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 : 2026-01-29DOI: 10.1016/j.nima.2026.171323
W. Hamdi , J. Crafts , H. Huang , Z. Huang , M. Kerver , M. Mathison , C. Ploen , A. Singh , T. Song , Y.P. Zhang , D. Adhikari , A. Ahmed , H. Albataineh , K. Aniol , A. Asaturyan , C. Ayerbe Gayoso , P. Bosted , E. Brash , A. Camsonne , J. Caylor , X. Zheng
The Neutral Particle Spectrometer (NPS) is an advanced calorimeter designed to measure neutral electromagnetic particles with high precision in energy, time, and position, under conditions of high luminosity and significant background. Integrated into the experimental setup of Hall C at Thomas Jefferson National Accelerator Facility, the NPS plays a critical role in studies of nucleon structure through exclusive and semi-inclusive reaction channels. This paper presents an assessment of the detector’s performance characteristics, specifically its energy and timing resolution, derived from elastic electron–proton scattering data. We report an energy resolution between 1.2% and 1.3% in the 4.5–7.3 GeV range, and an intrinsic timing resolution better than 200 ps for energies above 500 MeV. These results serve as a reference for current and future precision measurements in hadronic physics.
{"title":"Intrinsic energy and time resolution of the Jefferson Lab Hall C Neutral Particle Spectrometer","authors":"W. Hamdi , J. Crafts , H. Huang , Z. Huang , M. Kerver , M. Mathison , C. Ploen , A. Singh , T. Song , Y.P. Zhang , D. Adhikari , A. Ahmed , H. Albataineh , K. Aniol , A. Asaturyan , C. Ayerbe Gayoso , P. Bosted , E. Brash , A. Camsonne , J. Caylor , X. Zheng","doi":"10.1016/j.nima.2026.171323","DOIUrl":"10.1016/j.nima.2026.171323","url":null,"abstract":"<div><div>The Neutral Particle Spectrometer (NPS) is an advanced calorimeter designed to measure neutral electromagnetic particles with high precision in energy, time, and position, under conditions of high luminosity and significant background. Integrated into the experimental setup of Hall C at Thomas Jefferson National Accelerator Facility, the NPS plays a critical role in studies of nucleon structure through exclusive and semi-inclusive reaction channels. This paper presents an assessment of the detector’s performance characteristics, specifically its energy and timing resolution, derived from elastic electron–proton scattering data. We report an energy resolution between 1.2% and 1.3% in the 4.5–7.3 GeV range, and an intrinsic timing resolution better than 200 ps for energies above 500 MeV. These results serve as a reference for current and future precision measurements in hadronic physics.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171323"},"PeriodicalIF":1.4,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146070983","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 : 2026-01-29DOI: 10.1016/j.nima.2026.171321
Shikui Cheng , Qiubin Tang , Qiulei Yang , Yipo Zhang , Jie Zhang , Shuai Guan , Hongbing Xu
The runaway electron (RE) diagnostic system in the HL-3 tokamak has been equipped with a Lanthanum Bromide (LaBr(Ce)) detector and a full digital data acquisition system, ensuring that this system can achieve high energy resolution and spectral temporal resolution. During the HL-3 plasma discharges with pulsed gas injection, the hard X-ray (HXR) diagnostic signals exhibit rapid response characteristics. In the auxiliary heating experiments with electron cyclotron resonance wave, low hybrid wave or neutral beam injection, the population of runaway electrons can be significantly enhanced. Moreover, it has been observed that the fluctuation of unstable modes with frequencies between 100–400 kHz are positively correlated with the intensity of HXR radiation. The enhancement of REs loss induced by the growth of the unstable modes may provide a potential method to mitigate plasma disruptions and inhibit the formation of runaway current plateaus.
{"title":"Initial results of hard X-ray spectroscopy by LaBr3 (Ce) detector for runaway electron study at the HL-3 tokamak","authors":"Shikui Cheng , Qiubin Tang , Qiulei Yang , Yipo Zhang , Jie Zhang , Shuai Guan , Hongbing Xu","doi":"10.1016/j.nima.2026.171321","DOIUrl":"10.1016/j.nima.2026.171321","url":null,"abstract":"<div><div>The runaway electron (RE) diagnostic system in the HL-3 tokamak has been equipped with a Lanthanum Bromide (LaBr<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>(Ce)) detector and a full digital data acquisition system, ensuring that this system can achieve high energy resolution and spectral temporal resolution. During the HL-3 plasma discharges with pulsed gas injection, the hard X-ray (HXR) diagnostic signals exhibit rapid response characteristics. In the auxiliary heating experiments with electron cyclotron resonance wave, low hybrid wave or neutral beam injection, the population of runaway electrons can be significantly enhanced. Moreover, it has been observed that the fluctuation of unstable modes with frequencies between 100–400 kHz are positively correlated with the intensity of HXR radiation. The enhancement of REs loss induced by the growth of the unstable modes may provide a potential method to mitigate plasma disruptions and inhibit the formation of runaway current plateaus.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171321"},"PeriodicalIF":1.4,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081862","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 : 2026-01-28DOI: 10.1016/j.nima.2026.171331
Andrzej Rychter, Hyper-Kamiokande and WCTE Collaborations
The Hyper-Kamiokande experiment is a next-generation underground water Cherenkov detector designed to study CP violation, proton decay, and neutrinos from astrophysical sources with unprecedented sensitivity. To enhance photodetection performance, both the Far Detector (FD) and the Intermediate Water Cherenkov Detector (IWCD) employ novel multi-PMT (mPMT) modules. Two mPMT variants have been developed to meet the distinct operational requirements of the FD and IWCD. Each module integrates nineteen 3-inch photomultiplier tubes (PMTs) together with dedicated front-end electronics inside a waterproof pressure vessel. This architecture provides increased granularity, intrinsic directional sensitivity, and improved timing performance compared to conventional large-area PMTs. The FD will deploy 800 mPMT modules with a mechanical design engineered for operation at large depths and electronics optimized for ultra-low-power operation. The IWCD will use 400 mPMT modules as its primary photosensor system, featuring a modified mechanical design and waveform sampling electronics optimized for high event rates during beam spills. This paper presents the design, production, and performance of both mPMT architectures, highlighting their key mechanical and electrical differences and first system-level results from the Water Cherenkov Test Experiment at CERN.
{"title":"The design and performance of multi-PMT modules for the Hyper-Kamiokande experiment","authors":"Andrzej Rychter, Hyper-Kamiokande and WCTE Collaborations","doi":"10.1016/j.nima.2026.171331","DOIUrl":"10.1016/j.nima.2026.171331","url":null,"abstract":"<div><div>The Hyper-Kamiokande experiment is a next-generation underground water Cherenkov detector designed to study CP violation, proton decay, and neutrinos from astrophysical sources with unprecedented sensitivity. To enhance photodetection performance, both the Far Detector (FD) and the Intermediate Water Cherenkov Detector (IWCD) employ novel multi-PMT (mPMT) modules. Two mPMT variants have been developed to meet the distinct operational requirements of the FD and IWCD. Each module integrates nineteen 3-inch photomultiplier tubes (PMTs) together with dedicated front-end electronics inside a waterproof pressure vessel. This architecture provides increased granularity, intrinsic directional sensitivity, and improved timing performance compared to conventional large-area PMTs. The FD will deploy 800 mPMT modules with a mechanical design engineered for operation at large depths and electronics optimized for ultra-low-power operation. The IWCD will use 400 mPMT modules as its primary photosensor system, featuring a modified mechanical design and waveform sampling electronics optimized for high event rates during beam spills. This paper presents the design, production, and performance of both mPMT architectures, highlighting their key mechanical and electrical differences and first system-level results from the Water Cherenkov Test Experiment at CERN.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171331"},"PeriodicalIF":1.4,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078182","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 : 2026-01-28DOI: 10.1016/j.nima.2026.171335
Wangtao Yu , Peng Xu , Jie Bao , Man Zhou , Yuxin Lei , Yu Wang
The collimator is a critical component of fast neutron radiography system, as its performance directly influences both neutron beam quality and image resolution. In this paper, the simulation design and optimization of a multi-layer composite structure collimator is carried out for the D-T neutron generator. The optimal material, thickness for each functional layer, and the channel shape were determined using Geant4 simulations. Additionally, the designed collimator system was validated by simulating radiography of an iron slit sample and a tungsten block sample. Simulation results show that within a Ф30 mm field of view, the system exhibits a neutron fluence inhomogeneity of 2.78 %, a beam parallelism of 0.9955, an uncollided neutron fraction of 97.69 %, and a neutron-to-gamma fluence ratio of 40.81. The simulated imaging further confirms the system's good spatial resolution and its ability to provide a high-quality collimated neutron beam for high-performance fast neutron radiography. This study provides a reliable theoretical foundation and a systematic design methodology for collimators in D-T neutron generator-based fast neutron radiography systems.
{"title":"Simulation design of the collimator for fast neutron radiography system based on D-T neutron generator","authors":"Wangtao Yu , Peng Xu , Jie Bao , Man Zhou , Yuxin Lei , Yu Wang","doi":"10.1016/j.nima.2026.171335","DOIUrl":"10.1016/j.nima.2026.171335","url":null,"abstract":"<div><div>The collimator is a critical component of fast neutron radiography system, as its performance directly influences both neutron beam quality and image resolution. In this paper, the simulation design and optimization of a multi-layer composite structure collimator is carried out for the D-T neutron generator. The optimal material, thickness for each functional layer, and the channel shape were determined using Geant4 simulations. Additionally, the designed collimator system was validated by simulating radiography of an iron slit sample and a tungsten block sample. Simulation results show that within a Ф30 mm field of view, the system exhibits a neutron fluence inhomogeneity of 2.78 %, a beam parallelism of 0.9955, an uncollided neutron fraction of 97.69 %, and a neutron-to-gamma fluence ratio of 40.81. The simulated imaging further confirms the system's good spatial resolution and its ability to provide a high-quality collimated neutron beam for high-performance fast neutron radiography. This study provides a reliable theoretical foundation and a systematic design methodology for collimators in D-T neutron generator-based fast neutron radiography systems.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171335"},"PeriodicalIF":1.4,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146070982","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 new function to incorporate nuclear data libraries with outgoing particles plus residual nuclei in specific excitation states has been implemented in a Monte Carlo simulation code, Particle and Heavy Ion Transport code System (PHITS). With this function, accurate predictions of outgoing particle spectra and angular distributions according to the nuclear data libraries become possible, while accounting for production of residual nuclei and de-excitation gammas, conserving total energy and momentum in each event. This feature allows users to perform high-precision simulations of detector responses and radiation damage in materials.
{"title":"Implementation of a new function for handling nuclear data of outgoing particles and residual excitation states in PHITS","authors":"Takuya Furuta , Shintaro Hashimoto , Tatsuhiko Ogawa , Yoshihiko Tanimura","doi":"10.1016/j.nima.2026.171320","DOIUrl":"10.1016/j.nima.2026.171320","url":null,"abstract":"<div><div>A new function to incorporate nuclear data libraries with outgoing particles plus residual nuclei in specific excitation states has been implemented in a Monte Carlo simulation code, Particle and Heavy Ion Transport code System (PHITS). With this function, accurate predictions of outgoing particle spectra and angular distributions according to the nuclear data libraries become possible, while accounting for production of residual nuclei and de-excitation gammas, conserving total energy and momentum in each event. This feature allows users to perform high-precision simulations of detector responses and radiation damage in materials.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171320"},"PeriodicalIF":1.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146070981","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 : 2026-01-27DOI: 10.1016/j.nima.2026.171318
Artur Kalinowski, Wiktor Matyszkiewicz
The quality of the invariant mass reconstruction of the di- system is crucial for searches and analyses of di- resonances. Due to the presence of neutrinos in the final state, the invariant mass cannot be calculated directly at hadron colliders, where the longitudinal momentum sum constraint cannot be applied. A number of approaches have been adopted to mitigate this issue. The most general approach uses Matrix Element (ME) integration for likelihood estimation, followed by invariant mass reconstruction as the value that maximizes the likelihood. However, this method has a significant computational cost due to the need for integration over the phase space of the decay products. We propose an algorithm that reduces the computational cost by two orders of magnitude while maintaining the invariant mass reconstruction resolution at a level comparable to that of the ME-based method. Moreover, we introduce additional features that allow the estimation of the uncertainty of the reconstructed mass and the kinematics of the initial leptons (e.g. their momenta).
{"title":"Efficient tau-pair invariant mass reconstruction with simplified matrix element techniques","authors":"Artur Kalinowski, Wiktor Matyszkiewicz","doi":"10.1016/j.nima.2026.171318","DOIUrl":"10.1016/j.nima.2026.171318","url":null,"abstract":"<div><div>The quality of the invariant mass reconstruction of the di-<span><math><mi>τ</mi></math></span> system is crucial for searches and analyses of di-<span><math><mi>τ</mi></math></span> resonances. Due to the presence of neutrinos in the final state, the <span><math><mrow><mi>τ</mi><mi>τ</mi></mrow></math></span> invariant mass cannot be calculated directly at hadron colliders, where the longitudinal momentum sum constraint cannot be applied. A number of approaches have been adopted to mitigate this issue. The most general approach uses Matrix Element (ME) integration for likelihood estimation, followed by invariant mass reconstruction as the value that maximizes the likelihood. However, this method has a significant computational cost due to the need for integration over the phase space of the decay products. We propose an algorithm that reduces the computational cost by two orders of magnitude while maintaining the invariant mass reconstruction resolution at a level comparable to that of the ME-based method. Moreover, we introduce additional features that allow the estimation of the uncertainty of the reconstructed mass and the kinematics of the initial <span><math><mi>τ</mi></math></span> leptons (e.g. their momenta).</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171318"},"PeriodicalIF":1.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081866","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 : 2026-01-27DOI: 10.1016/j.nima.2026.171305
E. Navarrete Ramos , J. Villegas , J. Duarte-Campderros , M. Fernández , A. Gómez-Carrera , G. Gómez , J. González , S. Hidalgo , R. Jaramillo , P. Martínez Ruiz del Árbol , A. Merlos , C. Quintana , I. Vila
In this radiation tolerance study, Low Gain Avalanche Detectors (LGADs) with a carbon-enriched broad and shallow multiplication layer were examined in comparison to identical non-carbonated LGADs. Manufactured at IMB-CNM, the sensors underwent neutron irradiation at the TRIGRA reactor in Ljubljana, reaching a fluence of 2.5 × 1015 neq cm-2. The results revealed a smaller deactivation of Boron and improved resistance to radiation in carbonated LGADs. The study demonstrated the potential benefits of carbon enrichment in mitigating radiation damage effects, particularly the acceptor removal mechanism, reducing the acceptor removal constant by more than a factor of two. Additionally, time resolution and collected charge degradation due to irradiation were observed, with carbonated samples exhibiting better radiation tolerance. A noise analysis focused on baseline noise and thermally generated pulses showed the presence of spurious thermal-generated pulses attributed to a excessive small distance between the gain layer end and the p-stop implant at the periphery of the pad for the characterized LGAD design; however, the operation performance of the devices was unaffected.
{"title":"Effects of neutron irradiation on LGADs with broad multiplication layer and varied carbon-enriched doses: A study on timing performance and gain deterioration","authors":"E. Navarrete Ramos , J. Villegas , J. Duarte-Campderros , M. Fernández , A. Gómez-Carrera , G. Gómez , J. González , S. Hidalgo , R. Jaramillo , P. Martínez Ruiz del Árbol , A. Merlos , C. Quintana , I. Vila","doi":"10.1016/j.nima.2026.171305","DOIUrl":"10.1016/j.nima.2026.171305","url":null,"abstract":"<div><div>In this radiation tolerance study, Low Gain Avalanche Detectors (LGADs) with a carbon-enriched broad and shallow multiplication layer were examined in comparison to identical non-carbonated LGADs. Manufactured at IMB-CNM, the sensors underwent neutron irradiation at the TRIGRA reactor in Ljubljana, reaching a fluence of 2.5 × 10<sup>15</sup> <!-->n<sub>eq</sub> <!--> <!-->cm<sup>-2</sup>. The results revealed a smaller deactivation of Boron and improved resistance to radiation in carbonated LGADs. The study demonstrated the potential benefits of carbon enrichment in mitigating radiation damage effects, particularly the acceptor removal mechanism, reducing the acceptor removal constant by more than a factor of two. Additionally, time resolution and collected charge degradation due to irradiation were observed, with carbonated samples exhibiting better radiation tolerance. A noise analysis focused on baseline noise and thermally generated pulses showed the presence of spurious thermal-generated pulses attributed to a excessive small distance between the gain layer end and the p-stop implant at the periphery of the pad for the characterized LGAD design; however, the operation performance of the devices was unaffected.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171305"},"PeriodicalIF":1.4,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078188","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 : 2026-01-25DOI: 10.1016/j.nima.2026.171313
Hexin Wang , Huachang Liu , Zhencheng Mu , Hui Zhang , Linyan Rong , Zhexin Xie , Maliang Wan , Bo Wang , Bilawal Ali , Kai Guo , Xuanming Zhang , Shaozhe Wang , Yongming Li , Zhaoyun Duan , Yubin Gong
This paper reports the development and experimental validation of a compact metamaterial-loaded 324 MHz/3 MW klystron power system designed for the China Spallation Neutron Source (CSNS) proton linear accelerator. Conventional P-band klystrons deployed at CSNS, suffer from large physical dimensions and heavy weight, imposing constraints on system integration and cost. To address these limitations, a novel metamaterial-loaded klystron (M-klystron) incorporating complementary electric split-ring resonators (CeSRRs) and a second harmonic cavity is proposed, fabricated, and hot-tested. Particle-in-cell (PIC) simulations demonstrated that the M-klystron could achieve an output power of 2.97 MW at 324 MHz. The power system is driven by a self-developed long-pulse solid-state modulator, capable of delivering stable −110 kV, 51.5 A pulses at 25 Hz with a flat-top width of 950 μs, alongside a low-level RF (LLRF) control system ensuring precise amplitude and phase stabilization. Hot testing results confirmed a saturated output power of 3 MW with an efficiency of 53.1 % and a gain of 47.5 dB. Compared with the commercial klystron, the proposed M-klystron reduced cavities chain length from 3.5 m to 1.9 m, leading to volume reduction of nearly 50 %. These results highlight M-klystron's potential for compact, efficient RF sources in accelerator facilities as well as broader industrial and medical applications.
{"title":"Development and experiment of metamaterial loaded compact 324 MHz/3 MW klystron power system for CSNS proton linac","authors":"Hexin Wang , Huachang Liu , Zhencheng Mu , Hui Zhang , Linyan Rong , Zhexin Xie , Maliang Wan , Bo Wang , Bilawal Ali , Kai Guo , Xuanming Zhang , Shaozhe Wang , Yongming Li , Zhaoyun Duan , Yubin Gong","doi":"10.1016/j.nima.2026.171313","DOIUrl":"10.1016/j.nima.2026.171313","url":null,"abstract":"<div><div>This paper reports the development and experimental validation of a compact metamaterial-loaded 324 MHz/3 MW klystron power system designed for the China Spallation Neutron Source (CSNS) proton linear accelerator. Conventional P-band klystrons deployed at CSNS, suffer from large physical dimensions and heavy weight, imposing constraints on system integration and cost. To address these limitations, a novel metamaterial-loaded klystron (M-klystron) incorporating complementary electric split-ring resonators (CeSRRs) and a second harmonic cavity is proposed, fabricated, and hot-tested. Particle-in-cell (PIC) simulations demonstrated that the M-klystron could achieve an output power of 2.97 MW at 324 MHz. The power system is driven by a self-developed long-pulse solid-state modulator, capable of delivering stable −110 kV, 51.5 A pulses at 25 Hz with a flat-top width of 950 μs, alongside a low-level RF (LLRF) control system ensuring precise amplitude and phase stabilization. Hot testing results confirmed a saturated output power of 3 MW with an efficiency of 53.1 % and a gain of 47.5 dB. Compared with the commercial klystron, the proposed M-klystron reduced cavities chain length from 3.5 m to 1.9 m, leading to volume reduction of nearly 50 %. These results highlight M-klystron's potential for compact, efficient RF sources in accelerator facilities as well as broader industrial and medical 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 171313"},"PeriodicalIF":1.4,"publicationDate":"2026-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078181","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 : 2026-01-24DOI: 10.1016/j.nima.2026.171310
Yu Zhao , Jianliang Chen , Weihang Liu , Zhiping Li , Liangsheng Huang , Yanliang Han , Xingguang Liu , Shimin Jiang , Xiao Li , Yi Jiao , Sheng Wang
The Southern Advanced Photon Source (SAPS), a new 3.5 GeV ultra-low emittance ring-based light source, is planned to be built adjacent to the China Spallation Neutron Source in Dongguan. The SAPS project features a low-energy Linac and a booster serving as the pre-injector, and a storage ring design based on hybrid seven-bend achromat (H-7BA) with a circumference of 810 m. To achieve exceptional performance in terms of low emittance and high brightness, a novel unit cell, which consists of a bend combined with horizontal and longitudinal gradient (TLGB) in the center and two reverse bends neighboring the TLGB, is proposed to be used in the H-7BA. This innovative approach allows for a remarkable low natural emittance of 26.3 pm rad and a high brightness exceeding photons/s/mm2/mrad2/0.1% BW at a photon energy of about 4 keV. Furthermore, the optimized dynamic aperture and momentum aperture, even in the presence of realistic error conditions, satisfy the requirements for on-axis longitudinal injection, enabling beam accumulation. In this paper, details about lattice design and optimization, optics correction, injection scheme, collective effects and pre-injector design are presented.
{"title":"Key design features of the southern advanced photon source","authors":"Yu Zhao , Jianliang Chen , Weihang Liu , Zhiping Li , Liangsheng Huang , Yanliang Han , Xingguang Liu , Shimin Jiang , Xiao Li , Yi Jiao , Sheng Wang","doi":"10.1016/j.nima.2026.171310","DOIUrl":"10.1016/j.nima.2026.171310","url":null,"abstract":"<div><div>The Southern Advanced Photon Source (SAPS), a new 3.5 GeV ultra-low emittance ring-based light source, is planned to be built adjacent to the China Spallation Neutron Source in Dongguan. The SAPS project features a low-energy Linac and a booster serving as the pre-injector, and a storage ring design based on hybrid seven-bend achromat (H-7BA) with a circumference of 810 m. To achieve exceptional performance in terms of low emittance and high brightness, a novel unit cell, which consists of a bend combined with horizontal and longitudinal gradient (TLGB) in the center and two reverse bends neighboring the TLGB, is proposed to be used in the H-7BA. This innovative approach allows for a remarkable low natural emittance of 26.3 pm rad and a high brightness exceeding <span><math><mrow><mn>1</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>22</mn></mrow></msup></mrow></math></span> photons/s/mm<sup>2</sup>/mrad<sup>2</sup>/0.1% BW at a photon energy of about 4 keV. Furthermore, the optimized dynamic aperture and momentum aperture, even in the presence of realistic error conditions, satisfy the requirements for on-axis longitudinal injection, enabling beam accumulation. In this paper, details about lattice design and optimization, optics correction, injection scheme, collective effects and pre-injector design are presented.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171310"},"PeriodicalIF":1.4,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081864","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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