Pub Date : 2026-02-03DOI: 10.1016/j.nima.2026.171360
C.A. Alexe , J. Bendavid , L. Bianchini , D. Bruschini
We consider the problem of setting confidence intervals on a parameter of interest from the maximum-likelihood fit of a physics model to a binned data set with a large number of bins, large event-counts per bin, and in the presence of systematic uncertainties modeled as nuisance parameters. We use the profile-likelihood ratio for statistical inference and focus on the case in which the model is determined from Monte Carlo simulated samples of finite size. We start by presenting a toy model in which the properties of widely used approximations of the profile-likelihood ratio in the asymptotic limit, which are commonly expected to hold in the high-statistics regime, are manifestly broken even if the numbers of events per bin in both the data and simulated samples are seemingly large enough to warrant their validity. We then move to the general setting to show how statistical uncertainties in the Monte Carlo predictions can affect the coverage of confidence intervals constructed in the asymptotic approximation always in the same direction, namely they lead to systematic under-coverage.
{"title":"Under-coverage in high-statistics counting experiments with finite MC samples","authors":"C.A. Alexe , J. Bendavid , L. Bianchini , D. Bruschini","doi":"10.1016/j.nima.2026.171360","DOIUrl":"10.1016/j.nima.2026.171360","url":null,"abstract":"<div><div>We consider the problem of setting confidence intervals on a parameter of interest from the maximum-likelihood fit of a physics model to a binned data set with a large number of bins, large event-counts per bin, and in the presence of systematic uncertainties modeled as nuisance parameters. We use the profile-likelihood ratio for statistical inference and focus on the case in which the model is determined from Monte Carlo simulated samples of finite size. We start by presenting a toy model in which the properties of widely used approximations of the profile-likelihood ratio in the asymptotic limit, which are commonly expected to hold in the high-statistics regime, are manifestly broken even if the numbers of events per bin in both the data and simulated samples are seemingly large enough to warrant their validity. We then move to the general setting to show how statistical uncertainties in the Monte Carlo predictions can affect the coverage of confidence intervals constructed in the asymptotic approximation always in the same direction, namely they lead to systematic under-coverage.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171360"},"PeriodicalIF":1.4,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190976","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 : 2026-02-03DOI: 10.1016/j.nima.2026.171337
R. Li , D. Verney , C. Delafosse , M.N. Harakeh , A. Maj , F. Didierjean , L. Al Ayoubi , H. Al Falou , P. Bednarczyk , G. Benzoni , F. Le Blanc , V. Bozkurt , M. Ciemała , F.C.L. Crespi , I. Deloncle , C. Gaulard , A. Gottardo , V. Guadilla , J. Guillot , K. Hadyńska-Klęk , G. Tocabens
The different data-sorting modes of the phoswich detector array PARIS used for detecting high-energy (410 MeV) rays are investigated. The characteristics including time resolution, energy resolution and detection efficiency under various modes are studied. The present study shows that PARIS has capabilities of rejecting escape and pileup events when used for decay spectroscopy. Notably, the methods presented in this work refer specifically to the -decay experiment of Ga conducted with three PARIS clusters comprising 27 phoswich detectors, rather than to a general report on the PARIS array or its overall performance for in-beam spectroscopy. Compared with the 2”2”2” LaBr(Ce) detector (Ciemała et al., 2009), even in individual mode, PARIS provides significant suppression of single- and double-escape peaks and reduces background via vetoing function of the outer-volume NaI(Tl) crystals. In contrast to the common approach of adding back the energies in LaBr(Ce) and NaI(Tl) to increase the detection efficiency of the full-energy peak, using NaI(Tl) as a veto shield provides a superior trade-off for applications where spectral purity is essential. Employing add-back analysis within each cluster of nine phoswiches or between all phoswiches could enhance full-energy peak efficiency and further suppress escape peaks and background. Applying a multiplicity condition provides a further suppression but simultaneously lowers the statistics of full-energy peaks.
{"title":"Data sorting modes of phoswich detector array","authors":"R. Li , D. Verney , C. Delafosse , M.N. Harakeh , A. Maj , F. Didierjean , L. Al Ayoubi , H. Al Falou , P. Bednarczyk , G. Benzoni , F. Le Blanc , V. Bozkurt , M. Ciemała , F.C.L. Crespi , I. Deloncle , C. Gaulard , A. Gottardo , V. Guadilla , J. Guillot , K. Hadyńska-Klęk , G. Tocabens","doi":"10.1016/j.nima.2026.171337","DOIUrl":"10.1016/j.nima.2026.171337","url":null,"abstract":"<div><div>The different data-sorting modes of the phoswich detector array PARIS used for detecting high-energy (4<span><math><mo>−</mo></math></span>10 MeV) <span><math><mi>γ</mi></math></span> rays are investigated. The characteristics including time resolution, energy resolution and detection efficiency under various modes are studied. The present study shows that PARIS has capabilities of rejecting escape and pileup events when used for decay spectroscopy. Notably, the methods presented in this work refer specifically to the <span><math><mi>β</mi></math></span>-decay experiment of <span><math><msup><mrow></mrow><mrow><mn>80</mn><mi>g</mi><mo>+</mo><mi>m</mi></mrow></msup></math></span>Ga conducted with three PARIS clusters comprising 27 phoswich detectors, rather than to a general report on the PARIS array or its overall performance for in-beam spectroscopy. Compared with the 2”<span><math><mo>×</mo></math></span>2”<span><math><mo>×</mo></math></span>2” LaBr<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>(Ce) detector (Ciemała et al., 2009), even in individual mode, PARIS provides significant suppression of single- and double-escape peaks and reduces background via vetoing function of the outer-volume NaI(Tl) crystals. In contrast to the common approach of adding back the energies in LaBr<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>(Ce) and NaI(Tl) to increase the detection efficiency of the full-energy peak, using NaI(Tl) as a veto shield provides a superior trade-off for applications where spectral purity is essential. Employing add-back analysis within each cluster of nine phoswiches or between all phoswiches could enhance full-energy peak efficiency and further suppress escape peaks and background. Applying a multiplicity condition provides a further suppression but simultaneously lowers the statistics of full-energy peaks.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171337"},"PeriodicalIF":1.4,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190887","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 : 2026-02-03DOI: 10.1016/j.nima.2026.171357
S. Manna , T.K. Rana , Deepak Pandit , Sudip Ghosh , Saswata Roy , S. Kundu , K. Banerjee , P. Pant , R. Shil , R. Pandey
Characterization of a cylindrical CeBr detector, 2 crystal coupled to a photomultiplier tube (PMT) Hamamatsu R13089-100, has been carried out using various -ray sources with energies ranging from 81 to 4440 keV. The measured energy response of the detector has been compared with Geant4 simulation. The time response of the crystal, essential for several nuclear physics applications, has also been studied, yielding a time resolution of 260(1) ps for a single detector for 1173–1333 keV -ray cascade. Furthermore, the intrinsic efficiency of the detector has been determined and compared with simulation results—reported for the first time for this crystal size.
{"title":"Characterization of 2′′×2′′ CeBr3 scintillator detectors","authors":"S. Manna , T.K. Rana , Deepak Pandit , Sudip Ghosh , Saswata Roy , S. Kundu , K. Banerjee , P. Pant , R. Shil , R. Pandey","doi":"10.1016/j.nima.2026.171357","DOIUrl":"10.1016/j.nima.2026.171357","url":null,"abstract":"<div><div>Characterization of a cylindrical CeBr<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> detector, 2<span><math><mrow><msup><mrow></mrow><mrow><mo>′</mo><mo>′</mo></mrow></msup><mo>×</mo><msup><mrow><mn>2</mn></mrow><mrow><mo>′</mo><mo>′</mo></mrow></msup></mrow></math></span> crystal coupled to a photomultiplier tube (PMT) Hamamatsu R13089-100, has been carried out using various <span><math><mi>γ</mi></math></span>-ray sources with energies ranging from 81 to 4440 keV. The measured energy response of the detector has been compared with <span>Geant4</span> simulation. The time response of the crystal, essential for several nuclear physics applications, has also been studied, yielding a time resolution of 260(1) ps for a single detector for 1173–1333 keV <span><math><mi>γ</mi></math></span>-ray cascade. Furthermore, the intrinsic efficiency of the detector has been determined and compared with simulation results—reported for the first time for this crystal size.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171357"},"PeriodicalIF":1.4,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190891","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 : 2026-02-03DOI: 10.1016/j.nima.2026.171353
Rafael Ballabriga , Eric Buschmann , Michael Campbell , Raimon Casanova Mohr , Dominik Dannheim , Jona Dilg , Ana Dorda , Ono Feyens , Finn King , Philipp Gadow , Ingrid-Maria Gregor , Karsten Hansen , Yajun He , Lennart Huth , Iraklis Kremastiotis , Stephan Lachnit , Corentin Lemoine , Stefano Maffessanti , Larissa Mendes , Younes Otarid , Håkan Wennlöf
The H2M (Hybrid-to-Monolithic) is a monolithic pixel sensor manufactured in a modified 65 nm CMOS imaging process with a small collection electrode. Its design addresses the challenges of porting an existing hybrid pixel detector architecture into a monolithic chip, using a digital-on-top design methodology, and developing a compact digital cell library. Each square pixel integrates an analog front-end and digital pulse processing with an 8-bit counter within a 35 m pitch.
This contribution presents the performance of H2M based on laboratory and test beam measurements, including a comparison with analog front-end simulations in terms of gain and noise. A particular emphasis is placed on backside thinning in order to reduce material budget, down to a total chip thickness of 21 m for which no degradation in MIP detection performance is observed. For all investigated samples, a MIP detection efficiency above 99% is achieved below a threshold of approximately 205 electrons. At this threshold, the fake-hit rate corresponds to a matrix occupancy of fewer than one pixel per the 500 ns frame.
Measurements reveal a non-uniform in-pixel response, attributed to the formation of local potential wells in regions with low electric field. A simulation flow combining technology computer-aided design, Monte Carlo, and circuit simulations is used to investigate and describe this behavior, and is applied to develop mitigation strategies for future chip submissions with similar features.
{"title":"Characterization of the H2M monolithic CMOS sensor","authors":"Rafael Ballabriga , Eric Buschmann , Michael Campbell , Raimon Casanova Mohr , Dominik Dannheim , Jona Dilg , Ana Dorda , Ono Feyens , Finn King , Philipp Gadow , Ingrid-Maria Gregor , Karsten Hansen , Yajun He , Lennart Huth , Iraklis Kremastiotis , Stephan Lachnit , Corentin Lemoine , Stefano Maffessanti , Larissa Mendes , Younes Otarid , Håkan Wennlöf","doi":"10.1016/j.nima.2026.171353","DOIUrl":"10.1016/j.nima.2026.171353","url":null,"abstract":"<div><div>The H2M (Hybrid-to-Monolithic) is a monolithic pixel sensor manufactured in a modified 65 nm CMOS imaging process with a small collection electrode. Its design addresses the challenges of porting an existing hybrid pixel detector architecture into a monolithic chip, using a digital-on-top design methodology, and developing a compact digital cell library. Each square pixel integrates an analog front-end and digital pulse processing with an 8-bit counter within a 35 <span><math><mi>μ</mi></math></span>m pitch.</div><div>This contribution presents the performance of H2M based on laboratory and test beam measurements, including a comparison with analog front-end simulations in terms of gain and noise. A particular emphasis is placed on backside thinning in order to reduce material budget, down to a total chip thickness of 21 <span><math><mi>μ</mi></math></span>m for which no degradation in MIP detection performance is observed. For all investigated samples, a MIP detection efficiency above 99% is achieved below a threshold of approximately 205 electrons. At this threshold, the fake-hit rate corresponds to a matrix occupancy of fewer than one pixel per the 500 ns frame.</div><div>Measurements reveal a non-uniform in-pixel response, attributed to the formation of local potential wells in regions with low electric field. A simulation flow combining technology computer-aided design, Monte Carlo, and circuit simulations is used to investigate and describe this behavior, and is applied to develop mitigation strategies for future chip submissions with similar features.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171353"},"PeriodicalIF":1.4,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191075","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 : 2026-02-03DOI: 10.1016/j.nima.2026.171362
Meng Li , Philip Bambade , Dou Wang , Naoko Iida , Yoshihiro Funakoshi , Hiroshi Kaji , Yukiyoshi Ohnishi , Taichiro Koga , Jie Gao , Urbschat Bela , Hiroyuki Nakayama , Andrii Natochii , Haruyo Koiso , Kazuhito Ohmi , Kenta Uno , Qingyuan Liu
At SuperKEKB, the maximum achievable beam currents and the luminosity are projected to be constrained by beam injection in the near future. Recent attempts to squeeze the vertical beta function at the IP or increase beam currents have not yielded the expected improvements in luminosity, with poor injection performance in both rings being a major factor. The injection efficiencies are lower than half of the required value and large background signals are observed in the Belle II detector and other beam loss monitors. To avoid a sudden increase in background caused by injection, the Belle II trigger system is vetoed for several tens of milliseconds just after beam injection, leading to significant dead time. These injection issues are expected to become even more severe as luminosity increases, making beam injection one of the major bottleneck to achieving the target luminosity. To investigate and address these issues, detailed injection simulations for the high-energy ring (HER) were performed and compared with dedicated experimental measurements, providing valuable insights into injection-related beam loss mechanisms and offering practical strategies to improve injection efficiency while mitigating injection-induced backgrounds. This paper presents these findings together with their experimental validation.
{"title":"Injection-related beam loss in the high-energy ring of SuperKEKB","authors":"Meng Li , Philip Bambade , Dou Wang , Naoko Iida , Yoshihiro Funakoshi , Hiroshi Kaji , Yukiyoshi Ohnishi , Taichiro Koga , Jie Gao , Urbschat Bela , Hiroyuki Nakayama , Andrii Natochii , Haruyo Koiso , Kazuhito Ohmi , Kenta Uno , Qingyuan Liu","doi":"10.1016/j.nima.2026.171362","DOIUrl":"10.1016/j.nima.2026.171362","url":null,"abstract":"<div><div>At SuperKEKB, the maximum achievable beam currents and the luminosity are projected to be constrained by beam injection in the near future. Recent attempts to squeeze the vertical beta function at the IP or increase beam currents have not yielded the expected improvements in luminosity, with poor injection performance in both rings being a major factor. The injection efficiencies are lower than half of the required value and large background signals are observed in the Belle II detector and other beam loss monitors. To avoid a sudden increase in background caused by injection, the Belle II trigger system is vetoed for several tens of milliseconds just after beam injection, leading to significant dead time. These injection issues are expected to become even more severe as luminosity increases, making beam injection one of the major bottleneck to achieving the target luminosity. To investigate and address these issues, detailed injection simulations for the high-energy ring (HER) were performed and compared with dedicated experimental measurements, providing valuable insights into injection-related beam loss mechanisms and offering practical strategies to improve injection efficiency while mitigating injection-induced backgrounds. This paper presents these findings together with their experimental validation.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171362"},"PeriodicalIF":1.4,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190885","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 : 2026-02-02DOI: 10.1016/j.nima.2026.171355
Lin Zhou , Huanbo Feng , Zuke Feng , Difan Yi , Ran Chen , Kuan Liu , Lirong Xie , Qian Zhong , Jiangchuan Tuo , Tianyi Xiong , Fei Xie , Enwei Liang , Hongbang Liu
The Gas Microchannel Plate Pixel Detector (GMPD) is used in astrophysics for measuring X-ray polarization and serves as the prototype for the Low-Energy Polarization Detector (LPD) of the POLAR-2 project. During gamma-ray burst (GRB) observations, the incident flux can vary rapidly on short timescales, inducing charging-up effects that degrade gain stability. We characterize the chip-level charging-up behavior and quantify its impact on detector gain. To suppress this effect at the chip level, a 300 nm resistive film with a sheet resistance of is applied, effectively maintaining gain stability within 9% across varying operational conditions.
{"title":"The charging-up effects on Topmetal pixel chips for the polarization detection of GRBs","authors":"Lin Zhou , Huanbo Feng , Zuke Feng , Difan Yi , Ran Chen , Kuan Liu , Lirong Xie , Qian Zhong , Jiangchuan Tuo , Tianyi Xiong , Fei Xie , Enwei Liang , Hongbang Liu","doi":"10.1016/j.nima.2026.171355","DOIUrl":"10.1016/j.nima.2026.171355","url":null,"abstract":"<div><div>The Gas Microchannel Plate Pixel Detector (GMPD) is used in astrophysics for measuring X-ray polarization and serves as the prototype for the Low-Energy Polarization Detector (LPD) of the POLAR-2 project. During gamma-ray burst (GRB) observations, the incident flux can vary rapidly on short timescales, inducing charging-up effects that degrade gain stability. We characterize the chip-level charging-up behavior and quantify its impact on detector gain. To suppress this effect at the chip level, a 300 nm resistive film with a sheet resistance of <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>10</mn></mrow></msup><mspace></mspace><mi>Ω</mi><mo>/</mo><mi>sq</mi></mrow></math></span> is applied, effectively maintaining gain stability within 9% across varying operational conditions.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171355"},"PeriodicalIF":1.4,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190890","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 : 2026-02-02DOI: 10.1016/j.nima.2026.171356
N.S. Martorana , G. D’Agata , A. Barbon , G. Cardella , E. De Filippo , E. Geraci , C. Guazzoni , L. Acosta , C. Altana , A. Castoldi , A. Composto , S. De Luca , P. Figuera , B. Gnoffo , F. La Via , C. Maiolino , E.V. Pagano , S. Pirrone , G. Politi , L. Quattrocchi , C. Zagami
The development of new detectors based on Silicon Carbide (SiC) is currently a topic of interest within the scientific community. The significant features of SiC make it highly promising for detecting charged particles, neutrons, and /X radiation. In this framework, within the SAMOTHRACE (Sicilian Micro and Nano Technology Research and Innovation Center) ecosystem, an array of new-generation SiC detectors is under development, specifically designed for nuclear and medical investigations using radioactive ion beams. This paper describes the results obtained in the characterization of SiC prototypes regarding energy and timing measurements. A new method, based on coincidence data analysis, is employed to evaluate the timing performances of SiC detectors. The obtained results have been compared with tests performed using a micro-channel plate as a start detector reference for timing measurements.
{"title":"Evaluation of SiC detector performances for energy and timing measurements","authors":"N.S. Martorana , G. D’Agata , A. Barbon , G. Cardella , E. De Filippo , E. Geraci , C. Guazzoni , L. Acosta , C. Altana , A. Castoldi , A. Composto , S. De Luca , P. Figuera , B. Gnoffo , F. La Via , C. Maiolino , E.V. Pagano , S. Pirrone , G. Politi , L. Quattrocchi , C. Zagami","doi":"10.1016/j.nima.2026.171356","DOIUrl":"10.1016/j.nima.2026.171356","url":null,"abstract":"<div><div>The development of new detectors based on Silicon Carbide (SiC) is currently a topic of interest within the scientific community. The significant features of SiC make it highly promising for detecting charged particles, neutrons, and <span><math><mi>γ</mi></math></span>/X radiation. In this framework, within the SAMOTHRACE (Sicilian Micro and Nano Technology Research and Innovation Center) ecosystem, an array of new-generation SiC detectors is under development, specifically designed for nuclear and medical investigations using radioactive ion beams. This paper describes the results obtained in the characterization of SiC prototypes regarding energy and timing measurements. A new method, based on coincidence data analysis, is employed to evaluate the timing performances of SiC detectors. The obtained results have been compared with tests performed using a micro-channel plate as a start detector reference for timing measurements.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171356"},"PeriodicalIF":1.4,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191072","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 : 2026-02-02DOI: 10.1016/j.nima.2026.171317
T. Petruse , C. Matei , D.L. Balabanski , M. Costa , G.L. Guardo , I. Kuncser , M. La Cognata , D. Lattuada , A. Lupoae , H. Pai , A. Tumino , E. Udup , S. Aogaki
Extreme Light Infrastructure Silicon Strip Array (ELISSA), the silicon strip detector array developed at the Extreme Light Infrastructure - Nuclear Physics (ELI-NP) facility in collaboration with the Instituto Nazionale de Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS), is a 4 position-sensitive silicon strip array. The array is specifically designed to measure charged particles coming from photodisintegration reactions relevant for p-process nucleosynthesis and supernova explosions. The first in-beam tests of the ELISSA experimental set-up were performed at the 3 MV Tandetron accelerator of National Horia Hulubei National Institute for Research and Development in Physics and Nuclear Engineering (NIPNE). During this in-beam performance test, both analog and digital electronic modules were used to process the data. The performances (such as angular coverage, energy, and position resolution) of the silicon strip array are detailed in this paper. Alongside the measured characteristics, the simulation of the ELISSA array and a comparison of two read-out electronic chains and the two DAQ systems were also included.
{"title":"In-beam characterization of ELISSA: The 4π position-sensitive silicon strip array at ELI-NP","authors":"T. Petruse , C. Matei , D.L. Balabanski , M. Costa , G.L. Guardo , I. Kuncser , M. La Cognata , D. Lattuada , A. Lupoae , H. Pai , A. Tumino , E. Udup , S. Aogaki","doi":"10.1016/j.nima.2026.171317","DOIUrl":"10.1016/j.nima.2026.171317","url":null,"abstract":"<div><div>Extreme Light Infrastructure Silicon Strip Array (ELISSA), the silicon strip detector array developed at the Extreme Light Infrastructure - Nuclear Physics (ELI-NP) facility in collaboration with the Instituto Nazionale de Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS), is a 4<span><math><mi>π</mi></math></span> position-sensitive silicon strip array. The array is specifically designed to measure charged particles coming from photodisintegration reactions relevant for p-process nucleosynthesis and supernova explosions. The first in-beam tests of the ELISSA experimental set-up were performed at the 3 MV Tandetron accelerator of National Horia Hulubei National Institute for Research and Development in Physics and Nuclear Engineering (NIPNE). During this in-beam performance test, both analog and digital electronic modules were used to process the data. The performances (such as angular coverage, energy, and position resolution) of the silicon strip array are detailed in this paper. Alongside the measured characteristics, the simulation of the ELISSA array and a comparison of two read-out electronic chains and the two DAQ systems were also included.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171317"},"PeriodicalIF":1.4,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191071","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 : 2026-01-31DOI: 10.1016/j.nima.2026.171340
T. Frosio , J. Allan , J. Blaha , H. Brogognia , S. Rokny , M. Santana Leitner , S. Aderhold , M. Bai , S. Littleton
The Linac Coherent Light Source II (LCLS-II) at SLAC is a X-ray free-electron laser based on a 4 GeV superconducting linear accelerator capable of continuous-wave operation. While the machine has not yet reached its full design power, an initial phase of commissioning has focused on characterizing radiation produced by field emission, unintended electron discharge from RF cavities, which can impact beam quality, cause component damage, and create radiation hazards.
Using in situ diagnostics from the radiation safety system, including ionization chambers, synthetic diamond detectors, and Cherenkov fibers, we investigated field emissions originating from both the laser gun and cryomodules. For the gun, we characterized the captured current at the cathode and quantified the transmitted dark current through the beamline. By applying a dedicated methodology involving downstream collimators, we showed that a large fraction of the dark current can be intercepted by the collimation system.
For the cryomodules, we used radiation monitors and FLUKA simulations to estimate captured current and its evolution over time. Radiation was observed in several cavities, with field emission detected at gradients as low as 8 MV/m. Detailed analysis of some individual cryomodules revealed trends in backward and forward emission, enabling us to identify specific cavities contributing most to field-emitted current. These results support further mitigation strategies and provide a transferable approach to characterizing field emission in superconducting linacs.
{"title":"Radiation Physics commissioning of LCLS-II superconducting Linac. Gun and cryomodules commissioning","authors":"T. Frosio , J. Allan , J. Blaha , H. Brogognia , S. Rokny , M. Santana Leitner , S. Aderhold , M. Bai , S. Littleton","doi":"10.1016/j.nima.2026.171340","DOIUrl":"10.1016/j.nima.2026.171340","url":null,"abstract":"<div><div>The Linac Coherent Light Source II (LCLS-II) at SLAC is a X-ray free-electron laser based on a 4 GeV superconducting linear accelerator capable of continuous-wave operation. While the machine has not yet reached its full design power, an initial phase of commissioning has focused on characterizing radiation produced by field emission, unintended electron discharge from RF cavities, which can impact beam quality, cause component damage, and create radiation hazards.</div><div>Using in situ diagnostics from the radiation safety system, including ionization chambers, synthetic diamond detectors, and Cherenkov fibers, we investigated field emissions originating from both the laser gun and cryomodules. For the gun, we characterized the captured current at the cathode and quantified the transmitted dark current through the beamline. By applying a dedicated methodology involving downstream collimators, we showed that a large fraction of the dark current can be intercepted by the collimation system.</div><div>For the cryomodules, we used radiation monitors and FLUKA simulations to estimate captured current and its evolution over time. Radiation was observed in several cavities, with field emission detected at gradients as low as 8 MV/m. Detailed analysis of some individual cryomodules revealed trends in backward and forward emission, enabling us to identify specific cavities contributing most to field-emitted current. These results support further mitigation strategies and provide a transferable approach to characterizing field emission in superconducting linacs.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171340"},"PeriodicalIF":1.4,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190884","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 : 2026-01-31DOI: 10.1016/j.nima.2026.171322
Xi Huang , Kaiming Yuan , Hua Chen , Jinhui Qu , Zihang Song , Yonggang Yuan , Zhaoyi Tan
Non-destructive assay (NDA) plays a pivotal role in radioactive waste management, which can provide the crucial basis for radioactive waste safe classification, proper storage, and scientific disposal. In this paper, an improved non-destructive assay method for radioactive waste steel box is introduced. Given the large size and thickness of the steel box, the emission measurements of tomographic gamma scanning (TGS) was employed. The transmission measurements were replaced by Monte Carlo calculations based on the density of the uniform medium, to simplify the acquisition of the response matrix. The system response matrix library is pre-calculated to realize the adaptive calculation of activity reconstruction under different densities. In the actual experiments, three high-purity germanium (HPGe) detectors mounted on the measurement support platform were used to efficiently measure the full-energy peak counting rate of target nuclides. Based on the Boosted-Gold algorithm, the reconstruction of the radioactive waste activity distribution in steel box was accomplished. The errors in the actual activity measurement are less than 35% and 50% in uniform media (air, water and sand) and non-uniform medium (aluminum components), respectively. Moreover, the reconstructed activity distribution shows a high degree of consistency with the actual activity distribution. These results validate the capability of the proposed method and fully meet the requirements of non-destructive assay of radioactive waste steel box.
{"title":"An improved non-destructive assay method for radioactive waste steel boxes based on tomographic gamma scanning","authors":"Xi Huang , Kaiming Yuan , Hua Chen , Jinhui Qu , Zihang Song , Yonggang Yuan , Zhaoyi Tan","doi":"10.1016/j.nima.2026.171322","DOIUrl":"10.1016/j.nima.2026.171322","url":null,"abstract":"<div><div>Non-destructive assay (NDA) plays a pivotal role in radioactive waste management, which can provide the crucial basis for radioactive waste safe classification, proper storage, and scientific disposal. In this paper, an improved non-destructive assay method for radioactive waste steel box is introduced. Given the large size and thickness of the steel box, the emission measurements of tomographic gamma scanning (TGS) was employed. The transmission measurements were replaced by Monte Carlo calculations based on the density of the uniform medium, to simplify the acquisition of the response matrix. The system response matrix library is pre-calculated to realize the adaptive calculation of activity reconstruction under different densities. In the actual experiments, three high-purity germanium (HPGe) detectors mounted on the measurement support platform were used to efficiently measure the full-energy peak counting rate of target nuclides. Based on the Boosted-Gold algorithm, the reconstruction of the radioactive waste activity distribution in steel box was accomplished. The errors in the actual activity measurement are less than 35% and 50% in uniform media (air, water and sand) and non-uniform medium (aluminum components), respectively. Moreover, the reconstructed activity distribution shows a high degree of consistency with the actual activity distribution. These results validate the capability of the proposed method and fully meet the requirements of non-destructive assay of radioactive waste steel box.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171322"},"PeriodicalIF":1.4,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190889","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号