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}
The article presents the results of the work involving an experimental monitor designed to measure the neutron yield of pulsed neutron sources using the activation method. Indium is used as an activation material. The procedure for developing and manufacturing the device is described, including the justification of the moderator design and the configuration of secondary radiation counters, obtained using the Geant4 tools.
The results of the experiments on registering the pulsed neutron radiation with the energies of 2.5 and 14 MeV in the range of neutron yields from 4∙104 to 4∙1011 neutrons per pulse at 15–150 cm distances between the source and the front surface of the device are presented. The influence of the main factors contributing to the uncertainty of the measurement results is considered.
A method of pulse counting is described when the counters operate under excessive ultimate count rate. The method consists in the waiting for the activity to decrease to a critical level with subsequent backward extrapolation to the initial moment of time. This algorithm allows measuring the outputs of intense pulsed neutron sources, despite the limitations on the count rate of the detectors used.
{"title":"Neutron yield monitor for pulsed radiation sources","authors":"A.P. Denisenko , E.V. Ryabeva , R.F. Ibragimov , M. Yu Mishin , YuV. Mikhailov , V.P. Tarasov","doi":"10.1016/j.nima.2026.171314","DOIUrl":"10.1016/j.nima.2026.171314","url":null,"abstract":"<div><div>The article presents the results of the work involving an experimental monitor designed to measure the neutron yield of pulsed neutron sources using the activation method. Indium is used as an activation material. The procedure for developing and manufacturing the device is described, including the justification of the moderator design and the configuration of secondary radiation counters, obtained using the Geant4 tools.</div><div>The results of the experiments on registering the pulsed neutron radiation with the energies of 2.5 and 14 MeV in the range of neutron yields from 4∙10<sup>4</sup> to 4∙10<sup>11</sup> neutrons per pulse at 15–150 cm distances between the source and the front surface of the device are presented. The influence of the main factors contributing to the uncertainty of the measurement results is considered.</div><div>A method of pulse counting is described when the counters operate under excessive ultimate count rate. The method consists in the waiting for the activity to decrease to a critical level with subsequent backward extrapolation to the initial moment of time. This algorithm allows measuring the outputs of intense pulsed neutron sources, despite the limitations on the count rate of the detectors used.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171314"},"PeriodicalIF":1.4,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078187","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.2026.171316
D. Shatilov
The original article Zhang et al. (2025) can be logically divided into two parts: (1) the selection of main parameters for monochromatization and (2) interaction region optics design; the comment pertains only to the first part. The authors of Zhang et al. (2025) state that “The purpose of this paper is to report on the development of realistic IR optics designs for monochromatization at the FCC-ee”. However, the proposed parameters do not seem very realistic and raise many questions; due to space limitations, we will only consider the most important ones.
原文章Zhang et al.（2025）在逻辑上可以分为两个部分：(1)单色化主要参数的选择和(2)相互作用区光学设计；评论只涉及第一部分。Zhang等人（2025）的作者指出，“本文的目的是报告FCC-ee单色化实际红外光学设计的发展”。然而，所提出的参数似乎不太现实，并提出了许多问题；由于篇幅限制，我们将只考虑最重要的。
{"title":"Comment on “Monochromatization interaction region optics design for direct s-channel Higgs production at FCC-ee”","authors":"D. Shatilov","doi":"10.1016/j.nima.2026.171316","DOIUrl":"10.1016/j.nima.2026.171316","url":null,"abstract":"<div><div>The original article Zhang et al. (2025) can be logically divided into two parts: (1) the selection of main parameters for monochromatization and (2) interaction region optics design; the comment pertains only to the first part. The authors of Zhang et al. (2025) state that “The purpose of this paper is to report on the development of realistic IR optics designs for monochromatization at the FCC-ee”. However, the proposed parameters do not seem very realistic and raise many questions; due to space limitations, we will only consider the most important ones.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171316"},"PeriodicalIF":1.4,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081861","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.2026.171315
H.Y. Wu , Z.H. Li , M. Venaruzzo , L. Colombini , D.W. Luo , H. Hua , S. Nishimura , A. Abba , Y. Venturini , C. Tintori , M. Bianchini
Modern nuclear-physics experiments increasingly demand user-programmable triggering and real-time digital pulse processing under high channel density and high counting rates, where closed or fixed vendor firmware often becomes the limiting factor. We present a general-purpose digital data acquisition platform built around an open-FPGA firmware framework that enables users to develop and deploy custom trigger and pulse-processing algorithms on commercial waveform digitizers, while preserving a unified system-level control and monitoring workflow.
The system combines digitizers covering 125 MS/s–1 GS/s with a programmable logic module for crate-level coincidence/validation triggers, providing a hierarchical trigger architecture that supports both per-channel discrimination and external multi-board coincidences. Leveraging the open-FPGA approach, we implement and validate representative real-time algorithms, including (i) a five-segment summation energy filter designed to improve pile-up resilience at high rates, and (ii) pulse-shape-discrimination processing. A multi-threaded C++ software framework with a Qt-based GUI integrates configuration, high-throughput readout, real-time monitoring, and online analysis.
Performance evaluations demonstrate excellent energy resolution, stability at high count rates, and effective pulse share discrimination. The proposed framework provides a flexible and reproducible path to algorithm-driven DAQ customization for a wide range of detector systems.
{"title":"The upgrade of the general-purpose digital data acquisition system (GDDAQ)","authors":"H.Y. Wu , Z.H. Li , M. Venaruzzo , L. Colombini , D.W. Luo , H. Hua , S. Nishimura , A. Abba , Y. Venturini , C. Tintori , M. Bianchini","doi":"10.1016/j.nima.2026.171315","DOIUrl":"10.1016/j.nima.2026.171315","url":null,"abstract":"<div><div>Modern nuclear-physics experiments increasingly demand user-programmable triggering and real-time digital pulse processing under high channel density and high counting rates, where closed or fixed vendor firmware often becomes the limiting factor. We present a general-purpose digital data acquisition platform built around an open-FPGA firmware framework that enables users to develop and deploy custom trigger and pulse-processing algorithms on commercial waveform digitizers, while preserving a unified system-level control and monitoring workflow.</div><div>The system combines digitizers covering 125 MS/s–1 GS/s with a programmable logic module for crate-level coincidence/validation triggers, providing a hierarchical trigger architecture that supports both per-channel discrimination and external multi-board coincidences. Leveraging the open-FPGA approach, we implement and validate representative real-time algorithms, including (i) a five-segment summation energy filter designed to improve pile-up resilience at high rates, and (ii) pulse-shape-discrimination processing. A multi-threaded C++ software framework with a Qt-based GUI integrates configuration, high-throughput readout, real-time monitoring, and online analysis.</div><div>Performance evaluations demonstrate excellent energy resolution, stability at high count rates, and effective pulse share discrimination. The proposed framework provides a flexible and reproducible path to algorithm-driven DAQ customization for a wide range of detector systems.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171315"},"PeriodicalIF":1.4,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078180","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 : 2026-01-23DOI: 10.1016/j.nima.2026.171311
K. Dulski , E. Beyene , N. Chug , C. Curceanu , E. Czerwiński , M. Das , M. Gorgol , B. Jasińska , K. Kacprzak , Ł. Kapłon , G. Korcyl , T. Kozik , K. Kubat , D. Kumar , E. Lisowski , F. Lisowski , J. Mędrala-Sowa , S. Niedźwiecki , P. Pandey , S. Parzych , P. Moskal
Positron Annihilation Lifetime Spectroscopy (PALS) is a well-established non-destructive technique used for nanostructural characterization of porous materials. It is based on the annihilation of a positron and an electron. Mean positron lifetime in the material depends on the free voids size and molecular environment, allowing the study of porosity and structural transitions in the nanometer scale. We have developed a novel method enabling spatially resolved PALS, thus providing tomography of nanostructural characterization of an extended object. Correlating space (position) and structural (lifetime) information brings new insight in materials studies, especially in the characterization of the purity and pore distribution. For the first time, a porosity image using stationary positron sources for the simultaneous measurement of the porous polymers XAD4, silica aerogel powder IC3100, and polyvinyl toluene scintillator PVT by the J-PET (Jagiellonian Positron Emission Tomography) system is demonstrated.
{"title":"Nanoporosity imaging by positronium lifetime tomography","authors":"K. Dulski , E. Beyene , N. Chug , C. Curceanu , E. Czerwiński , M. Das , M. Gorgol , B. Jasińska , K. Kacprzak , Ł. Kapłon , G. Korcyl , T. Kozik , K. Kubat , D. Kumar , E. Lisowski , F. Lisowski , J. Mędrala-Sowa , S. Niedźwiecki , P. Pandey , S. Parzych , P. Moskal","doi":"10.1016/j.nima.2026.171311","DOIUrl":"10.1016/j.nima.2026.171311","url":null,"abstract":"<div><div>Positron Annihilation Lifetime Spectroscopy (PALS) is a well-established non-destructive technique used for nanostructural characterization of porous materials. It is based on the annihilation of a positron and an electron. Mean positron lifetime in the material depends on the free voids size and molecular environment, allowing the study of porosity and structural transitions in the nanometer scale. We have developed a novel method enabling spatially resolved PALS, thus providing tomography of nanostructural characterization of an extended object. Correlating space (position) and structural (lifetime) information brings new insight in materials studies, especially in the characterization of the purity and pore distribution. For the first time, a porosity image using stationary positron sources for the simultaneous measurement of the porous polymers XAD4, silica aerogel powder IC3100, and polyvinyl toluene scintillator PVT by the J-PET (Jagiellonian Positron Emission Tomography) system is demonstrated.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171311"},"PeriodicalIF":1.4,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190980","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 : 2026-01-23DOI: 10.1016/j.nima.2026.171297
Omar Abdelrahman , Gianluca Aglieri Rinella , Luca Aglietta , Giacomo Alocco , Matias Antonelli , Roberto Baccomi , Francesco Barile , Pascal Becht , Franco Benotto , Stefania Maria Beolè , Marcello Borri , Daniela Bortoletto , Naseem Bouchhar , Giuseppe Eugenio Bruno , Matthew Daniel Buckland , Szymon Bugiel , Paolo Camerini , Francesca Carnesecchi , Marielle Chartier , Domenico Colella , Alessandra Zingaretti
This paper presents the characterisation and testing of the first wafer-scale monolithic stitched sensor (MOSS) prototype developed for the ALICE ITS3 upgrade that is to be installed during the LHC Long Shutdown 3 (2026–2030). The MOSS chip design is driven by the truly cylindrical detector geometry that imposes that each layer is built out of two wafer-sized, bent silicon chips. The stitching technique is employed to fabricate sensors with dimensions of 1.4 cm 25.9 cm, thinned to 50 m. The chip architecture, the in-pixel front-end, the laboratory and in-beam characterisation, the susceptibility to single-event effects, and the series testing are discussed. The testing campaign validates the design of a wafer-scale stitched sensor and the performance of the pixel matrix to be within the ITS3 requirements. The MOSS chip demonstrates the feasibility of the ITS3 detector concept and provides insights for further optimisation and development.
本文介绍了为ALICE ITS3升级开发的第一个晶圆级单片缝合传感器（MOSS）原型的特性和测试，该原型将在大型强子对撞机长停堆3（2026-2030）期间安装。MOSS芯片的设计是由真正的圆柱形探测器几何结构驱动的，它要求每层都由两个晶圆大小的弯曲硅芯片组成。采用拼接技术制备了尺寸为1.4 cm × 25.9 cm、厚度为50 μm的传感器。讨论了芯片结构、像素内前端、实验室和光束内特性、单事件效应敏感性和系列测试。测试活动验证了晶圆级缝合传感器的设计和像素矩阵的性能符合ITS3的要求。MOSS芯片证明了ITS3探测器概念的可行性，并为进一步优化和开发提供了见解。
{"title":"Characterisation of the first wafer-scale prototype for the ALICE ITS3 upgrade: The monolithic stitched sensor (MOSS)","authors":"Omar Abdelrahman , Gianluca Aglieri Rinella , Luca Aglietta , Giacomo Alocco , Matias Antonelli , Roberto Baccomi , Francesco Barile , Pascal Becht , Franco Benotto , Stefania Maria Beolè , Marcello Borri , Daniela Bortoletto , Naseem Bouchhar , Giuseppe Eugenio Bruno , Matthew Daniel Buckland , Szymon Bugiel , Paolo Camerini , Francesca Carnesecchi , Marielle Chartier , Domenico Colella , Alessandra Zingaretti","doi":"10.1016/j.nima.2026.171297","DOIUrl":"10.1016/j.nima.2026.171297","url":null,"abstract":"<div><div>This paper presents the characterisation and testing of the first wafer-scale monolithic stitched sensor (MOSS) prototype developed for the ALICE ITS3 upgrade that is to be installed during the LHC Long Shutdown 3 (2026–2030). The MOSS chip design is driven by the truly cylindrical detector geometry that imposes that each layer is built out of two wafer-sized, bent silicon chips. The stitching technique is employed to fabricate sensors with dimensions of 1.4 cm <span><math><mo>×</mo></math></span> 25.9 cm, thinned to 50 <span><math><mi>μ</mi></math></span>m. The chip architecture, the in-pixel front-end, the laboratory and in-beam characterisation, the susceptibility to single-event effects, and the series testing are discussed. The testing campaign validates the design of a wafer-scale stitched sensor and the performance of the pixel matrix to be within the ITS3 requirements. The MOSS chip demonstrates the feasibility of the ITS3 detector concept and provides insights for further optimisation and development.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1086 ","pages":"Article 171297"},"PeriodicalIF":1.4,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081863","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 : 2026-01-23DOI: 10.1016/j.nima.2026.171309
Guodong Jiang , Yuan He , Longbo Shi , Kean Jin , Zhengrong Wu , Liepeng Sun , Chao Pan , Guirong Huang , Feng Qiu
This study investigates the feasibility of two-phase immersion cooling (2PIC) for 162.5 MHz LDMOS solid-state RF power amplifiers (SSPAs) in accelerator applications, addressing the challenges of high heat flux. Through the establishment of an electro-thermal coupling model and integration of isothermal RF experiments with immersion cooling tests, this work systematically compares the thermal management performance and RF characteristics of 2PIC against traditional water-cooled plates. Results show that under high input power (>−8 dBm), 2PIC reduces junction temperature by 35 °C and total thermal resistance by 53 % compared to water-cooled plates, while maintaining a 7.2 %–18 % increase in output power, an efficiency improvement of ∼5 % compared with water-cooled plates, and harmonic suppression better than −33 dBc. Optimization of coolant temperature and fill ratio further validates 2PIC's advantage in balancing phase-change heat transfer and RF stability. This research provides critical technical support for thermal management of next-generation accelerator SSPAs, confirming that 2PIC can simultaneously meet the dual requirements of high-power density heat dissipation and RF performance retention.
{"title":"Feasibility study of two-phase immersion cooling in accelerator solid-state RF power amplifiers","authors":"Guodong Jiang , Yuan He , Longbo Shi , Kean Jin , Zhengrong Wu , Liepeng Sun , Chao Pan , Guirong Huang , Feng Qiu","doi":"10.1016/j.nima.2026.171309","DOIUrl":"10.1016/j.nima.2026.171309","url":null,"abstract":"<div><div>This study investigates the feasibility of two-phase immersion cooling (2PIC) for 162.5 MHz LDMOS solid-state RF power amplifiers (SSPAs) in accelerator applications, addressing the challenges of high heat flux. Through the establishment of an electro-thermal coupling model and integration of isothermal RF experiments with immersion cooling tests, this work systematically compares the thermal management performance and RF characteristics of 2PIC against traditional water-cooled plates. Results show that under high input power (>−8 dBm), 2PIC reduces junction temperature by 35 °C and total thermal resistance by 53 % compared to water-cooled plates, while maintaining a 7.2 %–18 % increase in output power, an efficiency improvement of ∼5 % compared with water-cooled plates, and harmonic suppression better than −33 dBc. Optimization of coolant temperature and fill ratio further validates 2PIC's advantage in balancing phase-change heat transfer and RF stability. This research provides critical technical support for thermal management of next-generation accelerator SSPAs, confirming that 2PIC can simultaneously meet the dual requirements of high-power density heat dissipation and RF performance retention.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171309"},"PeriodicalIF":1.4,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024151","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 : 2026-01-22DOI: 10.1016/j.nima.2026.171299
F.G. Mo , Q. Tang , C. Guo , C.G. Yang , JUNO Collaboration
The Jiangmen Underground Neutrino Observatory (JUNO) is the state-of-the-art neutrino physics experiment located in South China. With 20 ktons of ultra-pure Liquid Scintillator, JUNO aims to achieve groundbreaking measurements, including the determination of the Neutrino Mass Ordering and a precise measurement of three neutrino oscillation parameters with sub-percent precision. The central detector is immersed in a Water Cherenkov Detector (WCD), which contains 40 ktons of ultrapure water and 2400 microchannel plate photomultipliers, serving dual purposes of radioactive background suppression from surrounding rock and cosmic muon tagging. The inner surface of the water pool’s wall is covered by 5 mm HDPE to prevent the rock emanating radon from diffusing into the water. Tyvek reflectors cover both the HDPE surface and the stainless lattice steel structure to enhance the light collection efficiency. A 100 t/h ultra-pure water system, which could reduce radon to mBq/m level and radium to Bq/m level, maintains high water quality and ensures optimal detector performance. A magnetic shielding system effectively mitigates geomagnetic field effects on PMT operation. The WCD demonstrates exceptional cosmic muon detection efficiency, exceeding 99% while suppressing muon-induced fast neutron backgrounds to 0.1 events per day. This paper will provide an overview of the design and current status of JUNO’s Water Cherenkov detector.
{"title":"JUNO’s Water Cherenkov Detector","authors":"F.G. Mo , Q. Tang , C. Guo , C.G. Yang , JUNO Collaboration","doi":"10.1016/j.nima.2026.171299","DOIUrl":"10.1016/j.nima.2026.171299","url":null,"abstract":"<div><div>The Jiangmen Underground Neutrino Observatory (JUNO) is the state-of-the-art neutrino physics experiment located in South China. With 20 ktons of ultra-pure Liquid Scintillator, JUNO aims to achieve groundbreaking measurements, including the determination of the Neutrino Mass Ordering and a precise measurement of three neutrino oscillation parameters with sub-percent precision. The central detector is immersed in a Water Cherenkov Detector (WCD), which contains 40 ktons of ultrapure water and 2400 microchannel plate photomultipliers, serving dual purposes of radioactive background suppression from surrounding rock and cosmic muon tagging. The inner surface of the water pool’s wall is covered by 5 mm HDPE to prevent the rock emanating radon from diffusing into the water. Tyvek reflectors cover both the HDPE surface and the stainless lattice steel structure to enhance the light collection efficiency. A 100 t/h ultra-pure water system, which could reduce radon to mBq/m<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span> level and radium to <span><math><mi>μ</mi></math></span>Bq/m<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span> level, maintains high water quality and ensures optimal detector performance. A magnetic shielding system effectively mitigates geomagnetic field effects on PMT operation. The WCD demonstrates exceptional cosmic muon detection efficiency, exceeding 99% while suppressing muon-induced fast neutron backgrounds to <span><math><mo>∼</mo></math></span>0.1 events per day. This paper will provide an overview of the design and current status of JUNO’s Water Cherenkov detector.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171299"},"PeriodicalIF":1.4,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078189","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 : 2026-01-22DOI: 10.1016/j.nima.2026.171308
C. Arcaro , J. Altet , X. Aragonès , E. Barajas , J.A. Barrio , J. Buces , L. Burmistrov , E. Charbon , R. de Menezes , F. Di Pierro , L. Giangrande , S. Gómez , M. Heller , D. Hoffmann , R. Isocrate , I. Jorge , A. Lòpez , R. Manera , D. Marín , F. Marini , L.Á. Tejedor Álvarez
An international collaboration is developing the advanced camera (AdvCam), the next-generation camera for Imaging Atmospheric Cherenkov Telescopes (IACTs), designed specifically for the Large-Sized Telescopes (LSTs) of the Cherenkov Telescope Array Observatory (CTAO), which feature a segmented mirror with a diameter of 23 m and a focal length of 28 m. AdvCam incorporates cutting-edge Silicon photomultipliers and a fully digital readout system, setting new standards for performance and efficiency.
The AdvCam will feature four times more channels than the existing PMT-based camera installed at LST-1. Covering the same field of view, this upgraded camera design enables finer image resolution and significantly improves the angular precision and background noise rejection. To cope with the increase in number of channels, many technological challenges are being tackled, from low-power and high-speed integrated chip design to real-time data processing on hardware accelerators.
This technological leap will lower the energy threshold by allowing telescopes to operate at a lower minimum signal level and providing brighter images with higher signal-to-noise ratio. The increase in effective area, angular resolution and energy resolution of this new-generation of IACTs will enhance CTAO’s sensitivity, unlocking new potential for gamma-ray astronomy. In this work, we present the performance of the AdvCam’s core building blocks and its innovative architecture capable of enabling unprecedented triggering capabilities. We also showcase the latest performance results based on Monte Carlo simulations that have been tuned to reflect the latest stages of the on-going technological developments, highlighting the transformative capabilities of this next-generation IACT camera.
{"title":"The AdvCam project: Designing the future cameras for the Large-Sized Telescopes of the Cherenkov Telescope Array Observatory","authors":"C. Arcaro , J. Altet , X. Aragonès , E. Barajas , J.A. Barrio , J. Buces , L. Burmistrov , E. Charbon , R. de Menezes , F. Di Pierro , L. Giangrande , S. Gómez , M. Heller , D. Hoffmann , R. Isocrate , I. Jorge , A. Lòpez , R. Manera , D. Marín , F. Marini , L.Á. Tejedor Álvarez","doi":"10.1016/j.nima.2026.171308","DOIUrl":"10.1016/j.nima.2026.171308","url":null,"abstract":"<div><div>An international collaboration is developing the advanced camera (AdvCam), the next-generation camera for Imaging Atmospheric Cherenkov Telescopes (IACTs), designed specifically for the Large-Sized Telescopes (LSTs) of the Cherenkov Telescope Array Observatory (CTAO), which feature a segmented mirror with a diameter of 23 m and a focal length of 28 m. AdvCam incorporates cutting-edge Silicon photomultipliers and a fully digital readout system, setting new standards for performance and efficiency.</div><div>The AdvCam will feature four times more channels than the existing PMT-based camera installed at LST-1. Covering the same field of view, this upgraded camera design enables finer image resolution and significantly improves the angular precision and background noise rejection. To cope with the increase in number of channels, many technological challenges are being tackled, from low-power and high-speed integrated chip design to real-time data processing on hardware accelerators.</div><div>This technological leap will lower the energy threshold by allowing telescopes to operate at a lower minimum signal level and providing brighter images with higher signal-to-noise ratio. The increase in effective area, angular resolution and energy resolution of this new-generation of IACTs will enhance CTAO’s sensitivity, unlocking new potential for gamma-ray astronomy. In this work, we present the performance of the AdvCam’s core building blocks and its innovative architecture capable of enabling unprecedented triggering capabilities. We also showcase the latest performance results based on Monte Carlo simulations that have been tuned to reflect the latest stages of the on-going technological developments, highlighting the transformative capabilities of this next-generation IACT camera.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1085 ","pages":"Article 171308"},"PeriodicalIF":1.4,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078179","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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