Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment最新文献

{"title":"Quality assurance tests and techniques to investigate and improve hermeticity of ATLAS Phase II Resistive Plate Chamber detectors","authors":"Aashaq Shah","doi":"10.1016/j.nima.2025.170510","DOIUrl":"10.1016/j.nima.2025.170510","url":null,"abstract":"<div><div>The Phase II upgrade of the ATLAS Muon Spectrometer will involve the installation of approximately 1000 next-generation single Resistive Plate Chamber (RPC) detectors, also referred to as singlets. This upgrade aims to enhance detector coverage, increase hit efficiency, and improve timing precision, ultimately strengthening the precision and robustness of the muon trigger system. The upgrade is essential for maintaining the performance of the muon spectrometer in the high-luminosity environment of the HL-LHC, where increased radiation and event rates pose significant challenges. Currently, detector production is underway, with gas gaps being produced in Italy. To ensure the integrity of these gas gaps, especially their mechanical properties and gas tightness, several investigative techniques have been proposed and implemented.</div><div>This study discusses the results of Thermal Cycling tests performed on ATLAS RPC gas gaps. These tests were conducted between <span><math><mrow><mo>−</mo><mn>33</mn><mo>°</mo></mrow></math></span>C and <span><math><mrow><mo>+</mo><mn>35</mn><mo>°</mo></mrow></math></span>C in a climate room at University of Cambridge and <span><math><mrow><mo>−</mo><mn>20</mn><mo>°</mo></mrow></math></span>C and <span><math><mrow><mo>+</mo><mn>30</mn><mo>°</mo></mrow></math></span>C in laboratories at INFN Frascati, providing insights into the effects of mechanical stress due to thermal expansion on gas leaks. Additionally, it outlines various methods employed to assess and enhance the gas tightness of the detectors. The ultimate objective is to produce hermetic RPC detectors, minimising the emission of environmentally harmful gases and mitigating their impact on global warming.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1076 ","pages":"Article 170510"},"PeriodicalIF":1.5,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820785","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}

{"title":"Performance of the ATLAS RPC detector and Level-1 muon barrel trigger with a new CO2-based gas mixture","authors":"Shixiang Su,&nbsp;ATLAS Collaboration","doi":"10.1016/j.nima.2025.170482","DOIUrl":"10.1016/j.nima.2025.170482","url":null,"abstract":"<div><div>Resistive Plate Chambers (RPCs) are used in the ATLAS experiment for trigger on muons in the barrel region. The current RPC detectors operate with a Freon-based gas mixture containing <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>F</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span> and <span><math><msub><mrow><mi>SF</mi></mrow><mrow><mn>6</mn></mrow></msub></math></span>, both of which have a high global warming potential. To reduce environmental impact and operating costs, it is essential to explore alternative, environmentally friendly gas mixtures. In August 2023, after the completion of proton–proton data-taking, the ATLAS collaboration replaced the standard gas mixture (94.7% <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>F</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span>, 5.0% <span><math><mrow><mi>i</mi><mtext>-</mtext><msub><mrow><mi>C</mi></mrow><mrow><mn>4</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>10</mn></mrow></msub></mrow></math></span>, 0.3% <span><math><msub><mrow><mi>SF</mi></mrow><mrow><mn>6</mn></mrow></msub></math></span>) with a new mixture with <span><math><msub><mrow><mi>CO</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> added: 64% <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>F</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span>, 30% <span><math><msub><mrow><mi>CO</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>, 5.0% <span><math><mrow><mi>i</mi><mtext>-</mtext><msub><mrow><mi>C</mi></mrow><mrow><mn>4</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>10</mn></mrow></msub></mrow></math></span>, 1% <span><math><msub><mrow><mi>SF</mi></mrow><mrow><mn>6</mn></mrow></msub></math></span>. This paper presents the performance of the RPC detector with the new mixture, focusing on detector current density, cluster size, and the efficiency of the Level-1 muon barrel trigger system.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1076 ","pages":"Article 170482"},"PeriodicalIF":1.5,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834375","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}

{"title":"Enhanced energy dispersive inelastic X-ray Scattering for advanced environmental monitoring","authors":"Daniela A. Riego ,&nbsp;Viviana M. Sbarato ,&nbsp;Roberto Daniel Perez","doi":"10.1016/j.nima.2025.170519","DOIUrl":"10.1016/j.nima.2025.170519","url":null,"abstract":"<div><div>One of the useful characteristics for evaluating the chemical speciation of a given element is to use the dependence of Resonant Inelastic X-ray Scattering (RIXS) on the electronic configuration of its environment. The remarkable amount of information provided by this methodology, combined with advances in high-intensity X-ray sources such as synchrotrons or FELs, has driven significant growth in RIXS in recent years. However, transferring this technique to conventional laboratories, while desirable, represents a major instrumentation challenge due to its low probability of occurrence, which becomes even more critical in specific applications such as studying heavy metal contamination. Indeed, in these studies, contaminant concentrations can be low, requiring maximum efficiency in sample excitation.</div><div>In the present work, we analyzed the possibility of using an X-ray tube as an excitation source for RIXS in the energy-dispersive configuration (EDIXS). To increase the efficiency of the experimental setup, an X-ray tube with an anode made of the same material as the element under study was used, combined with a monochromator that selected the characteristic Kβ line of the source. This line generally has a slightly lower energy but is very close to the K-edge of the element that produces it, thereby inducing resonant inelastic scattering with high probability.</div><div>The proposed configuration was implemented to analyze copper, using a monochromator with a large acceptance solid angle (12.5° aperture) based on a logarithmic spiral profile covered with 18 pieces of flat Si(100) crystal. The manufacturing and implementation processes of this monochromator, specifically for a copper X-ray tube, are described in detail in this work. The proposed EDIXS methodology, implemented with this device, was applied to a set of inorganic copper compounds to evaluate sensitivity to the chemical environment, achieving results similar to those previously reported using synchrotron radiation. Finally, the methodology was tested for monitoring the chemical state of copper absorbed by aquatic plants in a phytoremediation system, yielding satisfactory results in agreement with previous predictions. The proposed methodology offers a viable alternative for implementing RIXS in conventional laboratories, with sufficient sensitivity to analyze the chemical state of elements at concentrations as low as 1 % w/w, typically found in environmental contamination monitoring.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1076 ","pages":"Article 170519"},"PeriodicalIF":1.5,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834373","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}

{"title":"Outdoor MARTA RPCs performace update","authors":"L. Lopes ,&nbsp;P. Assis ,&nbsp;G. Neves ,&nbsp;R. Conceição ,&nbsp;M. Ferreira ,&nbsp;L. Mendes ,&nbsp;J.C. Nogueira","doi":"10.1016/j.nima.2025.170476","DOIUrl":"10.1016/j.nima.2025.170476","url":null,"abstract":"<div><div>Over the last two decades, the possibility of using RPCs in outdoors systems has increased considerably. Our group has participated in this effort having installed several systems and continues to work on their optimization, while simultaneously studying and developing new approaches that can lead to use of RPCs in outdoor applications.</div><div>In particular, some detectors, deployed in the field at the Pierre Auger Observatory in 2019, remained inactive, awaiting the commissioning of support systems. During the pandemic the detectors were left without gas flow for more than two years, until 2022 when they were filled with gas and HV was turned on. The behavior of 4 large area RPCs deployed under one of the AUGER water Cherenkov tanks will be presented.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1076 ","pages":"Article 170476"},"PeriodicalIF":1.5,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816698","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}

{"title":"First studies of crystal collimation for the FCC-ee","authors":"G. Broggi ,&nbsp;A. Abramov ,&nbsp;M. Boscolo ,&nbsp;R. Bruce ,&nbsp;D. Mirarchi ,&nbsp;S. Redaelli","doi":"10.1016/j.nima.2025.170479","DOIUrl":"10.1016/j.nima.2025.170479","url":null,"abstract":"<div><div>The Future Circular electron–positron Collider (FCC-ee) is being designed to push the energy and luminosity frontiers for lepton colliders. This requires managing unprecedented intensities of lepton beams, with stored beam energies up to 17.5 MJ. Therefore, a beam collimation system is essential not only for control of experimental backgrounds but also for safely disposing of unavoidable beam losses and ensuring machine availability. Unique challenges for the collimation system design need to be addressed, and the exploitation of channeling of charged particles in a bent-crystal-assisted collimation scheme is being explored as a possible solution to improve collimation performance. This paper presents the first studies to assess the feasibility of implementing such a collimation scheme in the FCC-ee.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1076 ","pages":"Article 170479"},"PeriodicalIF":1.5,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816697","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}

{"title":"From simulation to fabrication: Realizing silicon crystalline undulators with silicon nitride stressor layer patterning","authors":"L. Malagutti ,&nbsp;L. Bandiera ,&nbsp;F. Bonafè ,&nbsp;N. Canale ,&nbsp;D. De Salvador ,&nbsp;P. Fedeli ,&nbsp;V. Guidi ,&nbsp;A.V. Korol ,&nbsp;F. Mancarella ,&nbsp;R. Negrello ,&nbsp;G. Paternò ,&nbsp;M. Romagnoni ,&nbsp;F. Sgarbossa ,&nbsp;A.V. Solov’yov ,&nbsp;A. Sytov ,&nbsp;D. Valzani ,&nbsp;A. Mazzolari","doi":"10.1016/j.nima.2025.170480","DOIUrl":"10.1016/j.nima.2025.170480","url":null,"abstract":"<div><div>A crystalline undulator is a crystal exhibiting periodic deformations that cause channeled particles to oscillate, generating coherent electromagnetic waves. In this study, stressor layer patterning has been employed to induce the desired deformations on a silicon substrate. Finite element method simulations were performed to optimize the geometric parameters of the undulator. The primary focus was on achieving sinusoidal deformation with sub-millimeter period and amplitude exceeding 1 nm, utilizing the silicon (110) plane for its superior channeling properties. Key parameters, such as substrate thickness and undulator period, were meticulously refined to ensure uniform deformation while minimizing the impact of higher harmonics, which could degrade performance. Based on the simulation results, a crystalline undulator, 160 <span><math><mrow><mspace></mspace><mi>μ</mi><mtext>m</mtext></mrow></math></span> thick and consisting of 10 periods with a period length of 334 <span><math><mrow><mspace></mspace><mi>μ</mi><mtext>m</mtext></mrow></math></span>, has been successfully fabricated. The final device demonstrates structural integrity and a uniform deformation extending up to 20 <span><math><mrow><mspace></mspace><mi>μ</mi><mtext>m</mtext></mrow></math></span> from the surface. Specifically designed for use with 5–30 <!--> <!-->GeV particle beams, the undulator is capable of generating gamma photons in the 5–15 <!--> <!-->MeV range. This work effectively integrates advanced simulation techniques with precise fabrication methods, demonstrating the feasibility of crystalline undulators as high-performance devices for generating gamma radiation.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1076 ","pages":"Article 170480"},"PeriodicalIF":1.5,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838882","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}

{"title":"Innovative resistive plate chambers for the CMS phase-2 upgrade: Project summary, construction, and quality assurance","authors":"J. Vandenbroeck ,&nbsp;M. Tytgat ,&nbsp;K. Mota Amarilo ,&nbsp;A. Samalan ,&nbsp;K. Skovpen ,&nbsp;G.A. Alves ,&nbsp;E. Alves Coelho ,&nbsp;F. Marujo da Silva ,&nbsp;M. Barroso Ferreira Filho ,&nbsp;E.M. Da Costa ,&nbsp;D. De Jesus Damiao ,&nbsp;B.C. Ferreira ,&nbsp;S. Fonseca De Souza ,&nbsp;L. Mundim ,&nbsp;H. Nogima ,&nbsp;J.P. Pinheiro ,&nbsp;A. Santoro ,&nbsp;M. Thiel ,&nbsp;R. Gomes De Souza ,&nbsp;A. Aleksandrov ,&nbsp;J. Eysermans","doi":"10.1016/j.nima.2025.170453","DOIUrl":"10.1016/j.nima.2025.170453","url":null,"abstract":"<div><div>In view of the Phase-2 of the LHC physics program, called High Luminosity LHC (HL-LHC), the CMS muon system will be upgraded to maintain a robust muon triggering and reconstruction performance. Therefore RE3/1 and RE4/1 stations of the forward muon system will be equipped with new improved Resistive Plate Chambers (iRPC) as dedicated detectors for muon triggering in CMS. The new iRPC detectors have a different design and geometry with respect to the present RPC system to improve the rate capability and survive the harsh background condition during HL-LHC. This work summarizes the iRPC project including the iRPC design and production process, details of the ongoing detector production, quality control procedures at the production sites and results of performance studies with high energy muon beam under intense gamma radiation at the CERN Gamma Irradiation Facility (GIF++) facility.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1076 ","pages":"Article 170453"},"PeriodicalIF":1.5,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834376","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}

{"title":"Higher-order modes damping structure for 166.6 MHz superconducting radio-frequency cavity","authors":"Xuerui Hao ,&nbsp;Zhongquan Li ,&nbsp;Pei Zhang","doi":"10.1016/j.nima.2025.170448","DOIUrl":"10.1016/j.nima.2025.170448","url":null,"abstract":"<div><div>The development of fourth-generation synchrotron light sources necessitates enhanced beam stability. This study presents a broadband higher-order modes damping system designed for 166.6 MHz superconducting cavities in the High Energy Photon Source to mitigate coupled-bunch instabilities induced by higher-order modes impedance. Our systematic investigation focuses on higher-order modes suppression through optimized extraction structures, where extracted higher-order modes are effectively dissipated by absorbers while fundamental mode protection is ensured via narrow-band filters. Experimental validation confirms the feasibility of the proposed scheme, demonstrating significant improvement in higher-order modes suppression performance.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1076 ","pages":"Article 170448"},"PeriodicalIF":1.5,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816696","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}

{"title":"Radiation portal monitor data file format for comprehensive background radiation monitoring","authors":"JungHyun Bae ,&nbsp;Alexander Enders ,&nbsp;Charles Massey ,&nbsp;Jake Livesay ,&nbsp;Christopher Blessinger","doi":"10.1016/j.nima.2025.170516","DOIUrl":"10.1016/j.nima.2025.170516","url":null,"abstract":"<div><div>Radiation portal monitors (RPMs) are widely used at border security checkpoints to detect the presence of radioactive materials in people, vehicles, and cargo. Typically, RPM detection systems consist of two pillars equipped with gamma and neutron detectors. To improve detection efficiency, RPMs employ techniques such as a limited energy window, dynamic alarm thresholds, and lead shielding. However, without continuous monitoring of background radiation, signal interpretation can be compromised, because environmental factors and mechanical failures can cause fluctuations. Here, we introduce a daily file format that logs gamma background and neutron background radiation levels continuously over a 24 h period; this format is different from traditional formats that record data only when the RPM is active or occupied. The approach enables RPM operators and analysts to (1) identify and diagnose malfunctioning components, (2) adjust system settings to account for dynamic environmental factors, and (3) use the recorded data to characterize outer space phenomena. Continuous background reporting is essential for identifying issues such as faulty connections, voltage divider failures, and errors in background updates. Continuous background reporting also enables the detection of external influences, including nearby X-ray scanners, temperature fluctuations, rainfall, cosmic radiation, and lunar phase changes. These data files are designed to be easily evaluated and parsed using common tools, and a quick review by an expert is often sufficient for problem diagnosis. We anticipate that continuous background radiation monitoring and these new strategies will significantly improve the accuracy and reliability of RPM systems, reducing the rate of false alarms and enhancing overall system performance.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1076 ","pages":"Article 170516"},"PeriodicalIF":1.5,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834372","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}

{"title":"Evaluation of cosmogenic Ge-68 background in a high purity germanium detector via a time series fitting method","authors":"W.H. Dai ,&nbsp;J.K. Chen ,&nbsp;H. Ma ,&nbsp;Z. Zeng ,&nbsp;M.K. Jin ,&nbsp;Q.L. Zhang ,&nbsp;J.P. Cheng","doi":"10.1016/j.nima.2025.170472","DOIUrl":"10.1016/j.nima.2025.170472","url":null,"abstract":"<div><div>Ge-68 is a cosmogenic isotope in germanium with a half-life of 270.9 days. Ge-68 and its decay daughter Ga-68 contribute considerable background with energy up to 3 MeV to low background <span><math><mi>γ</mi></math></span> spectrometers using high purity germanium (HPGe) detectors. In this paper, we evaluated the background of Ge-68 and Ga-68 in a <span><math><mi>p</mi></math></span>-type coaxial HPGe detector operated at China Jinping underground laboratory (CJPL) via a time series fitting method. Under the assumption that Ge-68 and Ga-68 are in radioactive equilibrium and airborne radon daughters are uniformly distributed in the measurement chamber of the spectrometer, we fit the time series of count rate in 1-3 MeV to calculate the Ge-68 activity, radon daughter concentrations, and the time-invariant background component. A total of 90-day measurement data were used in the analysis, a hypothesis test confirmed a significant Ge-68 signal at 99.64% confidence level. The initial activity of Ge-68 is fitted to be 477.0<span><math><mrow><mo>±</mo><mn>112</mn><mo>.</mo><mn>4</mn><mi>μ</mi></mrow></math></span>Bq/kg, corresponding to an integral count rate of 55.9 count/day in the 1-3 MeV range. During the measurement, Ge-68 activity decreased by about 30%, contributing about 62% of the total background in the 1-3 MeV range. Our method also provides an estimation of the variation of airborne radon daughter concentrations in the measurement chamber, which could be used to monitor the performance of radon reduction measures.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1076 ","pages":"Article 170472"},"PeriodicalIF":1.5,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785265","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}