Pub Date : 2025-02-22DOI: 10.1016/j.nima.2025.170327
O.V. Bogdanov, S.V. Bragin
The generation of twisted photons during the motion of relativistic electrons in elliptical undulators has been studied. The influence of undulator ellipticity on the radiation intensity of twisted photons, asymmetry and selection rules when the undulator operates in the dipole and wiggler regime is investigated. Numerical calculations for prospective and existing elliptical undulators are presented.
{"title":"Peculiarities of generation of twisted photons in elliptic undulators","authors":"O.V. Bogdanov, S.V. Bragin","doi":"10.1016/j.nima.2025.170327","DOIUrl":"10.1016/j.nima.2025.170327","url":null,"abstract":"<div><div>The generation of twisted photons during the motion of relativistic electrons in elliptical undulators has been studied. The influence of undulator ellipticity on the radiation intensity of twisted photons, asymmetry and selection rules when the undulator operates in the dipole and wiggler regime is investigated. Numerical calculations for prospective and existing elliptical undulators are presented.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1075 ","pages":"Article 170327"},"PeriodicalIF":1.5,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479638","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 : 2025-02-21DOI: 10.1016/j.nima.2025.170322
A. Barresi, D. Chiesa, M. Nastasi, E. Previtali, M. Sisti
One of the main background sources of low background high purity germanium (HPGe) detectors is the cosmic muon showers produced in the interaction with the lead and copper shield surrounding the detector that can induce signals not distinguishable from radioactivity events. Plastic scintillators are widely used to implement active veto systems to reduce this contribution and increase the measurement sensitivity. In this work, we present the implementation of a high-efficiency muon veto system for the alpha-beta/gamma coincidence detector, called GeSparK. The veto system consists of six plastic scintillator detectors accurately positioned around the HPGe and liquid scintillator detectors. The final design includes two detectors above and four inside the passive shielding between the copper and lead layers. In this way, we can limit both their size and the event rate produced by external radioactivity, compared to the usual veto systems implemented outside the lead shielding. A dedicated background measurement showed that the achieved background reduction is a bit less than 93%.
{"title":"Implementation of a high-efficiency muon veto system for the GeSparK alpha-beta/gamma coincidence detector","authors":"A. Barresi, D. Chiesa, M. Nastasi, E. Previtali, M. Sisti","doi":"10.1016/j.nima.2025.170322","DOIUrl":"10.1016/j.nima.2025.170322","url":null,"abstract":"<div><div>One of the main background sources of low background high purity germanium (HPGe) detectors is the cosmic muon showers produced in the interaction with the lead and copper shield surrounding the detector that can induce signals not distinguishable from radioactivity events. Plastic scintillators are widely used to implement active veto systems to reduce this contribution and increase the measurement sensitivity. In this work, we present the implementation of a high-efficiency muon veto system for the alpha-beta/gamma coincidence detector, called GeSparK. The veto system consists of six plastic scintillator detectors accurately positioned around the HPGe and liquid scintillator detectors. The final design includes two detectors above and four inside the passive shielding between the copper and lead layers. In this way, we can limit both their size and the event rate produced by external radioactivity, compared to the usual veto systems implemented outside the lead shielding. A dedicated background measurement showed that the achieved background reduction is a bit less than 93%.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1075 ","pages":"Article 170322"},"PeriodicalIF":1.5,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-21DOI: 10.1016/j.nima.2025.170333
D.W. Luo , C.Y. Guo , S.Y. Zhang , Z.X. Zhou , D.X. Wang , H.Y. Wu , Z.H. Li , H. Hua , L. Ni , J.Z. Zhang , Z. Liu , W.Q. Zhang , H. Huang , Q.B. Zeng , Z.G. Gan , Z.Y. Zhang , M.H. Huang , H.B. Yang , L. Ma , J.G. Wang , M.M. Zhang
A focal plane detector system was implemented at the gas-filled recoil separator SHANS for the decay studies of heavy isotopes. The performance of the system using standard sources and in-beam experiments was described. A significant reduction of the background induced by light-charged particles was achieved using pulse shape analysis techniques with the digital electronics. In addition, the detector system allows the measurements of internal conversion electrons with a low energy threshold of about 100 keV.
{"title":"The implementation of a focal plane detector system at the gas-filled recoil separator for the decay studies of heavy nuclei","authors":"D.W. Luo , C.Y. Guo , S.Y. Zhang , Z.X. Zhou , D.X. Wang , H.Y. Wu , Z.H. Li , H. Hua , L. Ni , J.Z. Zhang , Z. Liu , W.Q. Zhang , H. Huang , Q.B. Zeng , Z.G. Gan , Z.Y. Zhang , M.H. Huang , H.B. Yang , L. Ma , J.G. Wang , M.M. Zhang","doi":"10.1016/j.nima.2025.170333","DOIUrl":"10.1016/j.nima.2025.170333","url":null,"abstract":"<div><div>A focal plane detector system was implemented at the gas-filled recoil separator SHANS for the decay studies of heavy isotopes. The performance of the system using standard sources and in-beam experiments was described. A significant reduction of the background induced by light-charged particles was achieved using pulse shape analysis techniques with the digital electronics. In addition, the detector system allows the measurements of internal conversion electrons with a low energy threshold of about 100 keV.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1075 ","pages":"Article 170333"},"PeriodicalIF":1.5,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479636","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 : 2025-02-20DOI: 10.1016/j.nima.2025.170313
Hayk L. Gevorgyan , Koryun L. Gevorgyan , Anahit H. Shamamian , Lekdar A. Gevorgian
The problem of undulator radiation from a bunch of charged particles, taking into account a medium polarization, is considered. In a dispersive medium, at a zero angle, in addition to hard photons, soft photons are also generated. A formula for the frequency-angular distribution of the number of radiated soft and hard photons has been obtained. If the wavelength of the soft photons is greater than or equal to the longitudinal size of the microbunches formed during the XFEL process, the microbunches radiate coherently. Consequently, the radiation of the bunch will be partially coherent. As a result, intense, quasi-monochromatic, and directed X-ray photon beams are produced, which can have wide practical applications.
{"title":"Line shape of soft photon radiation generated at zero angle in an undulator with a dispersive medium","authors":"Hayk L. Gevorgyan , Koryun L. Gevorgyan , Anahit H. Shamamian , Lekdar A. Gevorgian","doi":"10.1016/j.nima.2025.170313","DOIUrl":"10.1016/j.nima.2025.170313","url":null,"abstract":"<div><div>The problem of undulator radiation from a bunch of charged particles, taking into account a medium polarization, is considered. In a dispersive medium, at a zero angle, in addition to hard photons, soft photons are also generated. A formula for the frequency-angular distribution of the number of radiated soft and hard photons has been obtained. If the wavelength of the soft photons is greater than or equal to the longitudinal size of the microbunches formed during the XFEL process, the microbunches radiate coherently. Consequently, the radiation of the bunch will be partially coherent. As a result, intense, quasi-monochromatic, and directed X-ray photon beams are produced, which can have wide practical applications.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1075 ","pages":"Article 170313"},"PeriodicalIF":1.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479542","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 : 2025-02-20DOI: 10.1016/j.nima.2025.170357
Hang Zhou , Kexin Sun , Zhenna Lu , Hao Li , Xiaocong Ai , Jin Zhang , Xingtao Huang , Jianbei Liu
The proposed Super Tau-Charm Facility (STCF) is an electron-positron collider designed to operate in a center-of-mass energy range from 2 to 7 GeV. It provides a unique platform for physics research in the tau-charm energy region. To fulfill the physics goals of STCF, high tracking efficiency and good momentum resolution is required for charged particles with momenta from 50 MeV/c to 3.5 GeV/c. A global track finding algorithm based on Hough transform has been developed and implemented in the STCF software framework to meet this requirement. The design of the algorithm and its performance with simulation are presented in this paper.
{"title":"Global track finding based on the Hough transform in the STCF detector","authors":"Hang Zhou , Kexin Sun , Zhenna Lu , Hao Li , Xiaocong Ai , Jin Zhang , Xingtao Huang , Jianbei Liu","doi":"10.1016/j.nima.2025.170357","DOIUrl":"10.1016/j.nima.2025.170357","url":null,"abstract":"<div><div>The proposed Super Tau-Charm Facility (STCF) is an electron-positron collider designed to operate in a center-of-mass energy range from 2 to 7 GeV. It provides a unique platform for physics research in the tau-charm energy region. To fulfill the physics goals of STCF, high tracking efficiency and good momentum resolution is required for charged particles with momenta from 50 MeV/c to 3.5 GeV/c. A global track finding algorithm based on Hough transform has been developed and implemented in the STCF software framework to meet this requirement. The design of the algorithm and its performance with simulation are presented in this paper.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1075 ","pages":"Article 170357"},"PeriodicalIF":1.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488446","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 : 2025-02-20DOI: 10.1016/j.nima.2025.170318
Antonio Bianchi
Resistive Plate Chambers (RPCs), widely used in particle detection, offer high efficiency, excellent time resolution, and cost-effectiveness. The environmental impact of gases such as tetrafluoroethane and sulfur hexafluoride, commonly used in RPCs, has driven research into more sustainable gas mixtures.
This study explores the accuracy of simulating the electron swarm parameters in environmentally friendly gas mixtures for RPCs, particularly focusing on the potential substitution of the gas tetrafluoroethane (C2H2F4) with tetrafluoropropene (C3H2F4). Using Monte Carlo simulations with the MATOQ framework, we demonstrate agreement with experimental measurements recently obtained from RPCs operating with C3H2F4-based gas mixtures at room temperature and atmospheric pressure. This confirms the accuracy of the electron collision cross sections for C3H2F4 available in the literature, extending their validation from 45 kPa to atmospheric pressure, and strengthening their reliability for simulations focused on RPC applications.
The benchmark of electron collision cross sections for C3H2F4 paves the way for future research aimed at optimizing environmentally friendly gas mixtures for RPCs. Results of this study show that the effective Townsend coefficient can vary by more than an order of magnitude when C3H2F4 is mixed with molecular oxygen, nitrogen, carbon dioxide, argon, or helium. These findings support a viable strategy for lowering the working point of RPCs by combining C3H2F4 with another gas that has a low global warming potential, as demonstrated by various experimental studies. Variations in electron drift velocity, a key factor in determining the time resolution of RPCs, have also been observed when C3H2F4 is combined with the aforementioned atmospheric gases.
{"title":"Advancements in the simulation of environmentally friendly gas mixtures for Resistive Plate Chambers","authors":"Antonio Bianchi","doi":"10.1016/j.nima.2025.170318","DOIUrl":"10.1016/j.nima.2025.170318","url":null,"abstract":"<div><div>Resistive Plate Chambers (RPCs), widely used in particle detection, offer high efficiency, excellent time resolution, and cost-effectiveness. The environmental impact of gases such as tetrafluoroethane and sulfur hexafluoride, commonly used in RPCs, has driven research into more sustainable gas mixtures.</div><div>This study explores the accuracy of simulating the electron swarm parameters in environmentally friendly gas mixtures for RPCs, particularly focusing on the potential substitution of the gas tetrafluoroethane (C<sub>2</sub>H<sub>2</sub>F<sub>4</sub>) with tetrafluoropropene (C<sub>3</sub>H<sub>2</sub>F<sub>4</sub>). Using Monte Carlo simulations with the MATOQ framework, we demonstrate agreement with experimental measurements recently obtained from RPCs operating with C<sub>3</sub>H<sub>2</sub>F<sub>4</sub>-based gas mixtures at room temperature and atmospheric pressure. This confirms the accuracy of the electron collision cross sections for C<sub>3</sub>H<sub>2</sub>F<sub>4</sub> available in the literature, extending their validation from 45 kPa to atmospheric pressure, and strengthening their reliability for simulations focused on RPC applications.</div><div>The benchmark of electron collision cross sections for C<sub>3</sub>H<sub>2</sub>F<sub>4</sub> paves the way for future research aimed at optimizing environmentally friendly gas mixtures for RPCs. Results of this study show that the effective Townsend coefficient can vary by more than an order of magnitude when C<sub>3</sub>H<sub>2</sub>F<sub>4</sub> is mixed with molecular oxygen, nitrogen, carbon dioxide, argon, or helium. These findings support a viable strategy for lowering the working point of RPCs by combining C<sub>3</sub>H<sub>2</sub>F<sub>4</sub> with another gas that has a low global warming potential, as demonstrated by various experimental studies. Variations in electron drift velocity, a key factor in determining the time resolution of RPCs, have also been observed when C<sub>3</sub>H<sub>2</sub>F<sub>4</sub> is combined with the aforementioned atmospheric gases.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1075 ","pages":"Article 170318"},"PeriodicalIF":1.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-20DOI: 10.1016/j.nima.2025.170352
O. Ashraf , Nada M. Nobei , Ayman M. Abdalla , A.M. Ismail , E.M. Awad , A.H. Ashry
The latent tracks formed on CR-39 solid state nuclear track detector on exposure of alpha particles and fission fragments (FF) emitted from collimated 241Am and 252Cf sources were developed by a chemical etching method. In this study, we use molten hydrated barium hydroxide (MBH) as an etching solution to register FF. In this experiment, one set of detectors were exposed to FF from 252Cf radioactive source with activity (1.84 μCi). The second set of detectors has been exposed to alpha particles with different energies ranging from 1 to 5 MeV. The irradiated samples were etched with MBH at different temperatures (78 °C, 80 °C, 85 °C, and 90 °C) for different periods ranging from 2 to 20 min. We calculated etching parameters including bulk etching rate, track etching rate, sensitivity, etching efficiency, and activation energy (EB and ET). The main advantage of the current method lies in its ability to achieve efficient etching of CR-39 detectors at a temperature of 90 °C with an etch rate (VB) of 14.67 μm/h and an etching duration of 16 min. Furthermore, we identified the optimal etching conditions for detecting alpha particles in CR-39 detectors, aiming for short etching durations.
{"title":"MBH as an etching solution for fast detection of alpha particles and fission fragments using CR-39 detector","authors":"O. Ashraf , Nada M. Nobei , Ayman M. Abdalla , A.M. Ismail , E.M. Awad , A.H. Ashry","doi":"10.1016/j.nima.2025.170352","DOIUrl":"10.1016/j.nima.2025.170352","url":null,"abstract":"<div><div>The latent tracks formed on CR-39 solid state nuclear track detector on exposure of alpha particles and fission fragments (FF) emitted from collimated <sup>241</sup>Am and <sup>252</sup>Cf sources were developed by a chemical etching method. In this study, we use molten hydrated barium hydroxide (MBH) as an etching solution to register FF. In this experiment, one set of detectors were exposed to FF from <sup>252</sup>Cf radioactive source with activity (1.84 μCi). The second set of detectors has been exposed to alpha particles with different energies ranging from 1 to 5 MeV. The irradiated samples were etched with MBH at different temperatures (78 °C, 80 °C, 85 °C, and 90 °C) for different periods ranging from 2 to 20 min. We calculated etching parameters including bulk etching rate, track etching rate, sensitivity, etching efficiency, and activation energy (E<sub>B</sub> and E<sub>T</sub>). The main advantage of the current method lies in its ability to achieve efficient etching of CR-39 detectors at a temperature of 90 °C with an etch rate (V<sub>B</sub>) of 14.67 μm/h and an etching duration of 16 min. Furthermore, we identified the optimal etching conditions for detecting alpha particles in CR-39 detectors, aiming for short etching durations.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1075 ","pages":"Article 170352"},"PeriodicalIF":1.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143473970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A laser-based resonance ionization-Paul trap mass spectrometer was initially designed for trace analysis of 90Sr by combining resonance ionization, quadrupole mass spectrometry, and ion trap mass spectrometry. This apparatus has been proven capable of capturing 90Sr ions in our previous research. A new ion guide assembly, located between the quadrupole mass spectrometer and the ion trap, has been developed and is the focus of this paper. This new ion guide is designed to decelerate the selected 90Sr ions after the quadrupole mass spectrometer and efficiently transport them into the ion trap.
In this paper, we report the construction of the ion trap-laser cooling spectrometer (ITLCS) along with modeling and simulation results to evaluate its performance. Corresponding parameters, such as the 90Sr ions' transmission rate through the ion guide and the capture rate of the ion trap, have been simulated and analyzed. The simulation results demonstrate that the capture rate for the 90Sr ions in ITLCS reached approximately 17%. Furthermore, initial experiments using natural metallic Sr samples were conducted to validate the system's core functionalities, including ion production through resonant ionization, mass selection, transport via the ion guide, and injection into the ion trap. These results provide a solid foundation for future optimization and application of the ITLCS in trace isotope analysis.
{"title":"Design and simulation for a 90Sr ion trap – laser cooling spectrometer","authors":"Chao Zhang , Ryohei Terabayashi , Shuichi Hasegawa","doi":"10.1016/j.nima.2025.170321","DOIUrl":"10.1016/j.nima.2025.170321","url":null,"abstract":"<div><div>A laser-based resonance ionization-Paul trap mass spectrometer was initially designed for trace analysis of <sup>90</sup>Sr by combining resonance ionization, quadrupole mass spectrometry, and ion trap mass spectrometry. This apparatus has been proven capable of capturing <sup>90</sup>Sr ions in our previous research. A new ion guide assembly, located between the quadrupole mass spectrometer and the ion trap, has been developed and is the focus of this paper. This new ion guide is designed to decelerate the selected <sup>90</sup>Sr ions after the quadrupole mass spectrometer and efficiently transport them into the ion trap.</div><div>In this paper, we report the construction of the ion trap-laser cooling spectrometer (ITLCS) along with modeling and simulation results to evaluate its performance. Corresponding parameters, such as the 90Sr ions' transmission rate through the ion guide and the capture rate of the ion trap, have been simulated and analyzed. The simulation results demonstrate that the capture rate for the <sup>90</sup>Sr ions in ITLCS reached approximately 17%. Furthermore, initial experiments using natural metallic Sr samples were conducted to validate the system's core functionalities, including ion production through resonant ionization, mass selection, transport via the ion guide, and injection into the ion trap. These results provide a solid foundation for future optimization and application of the ITLCS in trace isotope analysis.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1074 ","pages":"Article 170321"},"PeriodicalIF":1.5,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18DOI: 10.1016/j.nima.2025.170310
N. Akchurin, T. Peltola
<div><div>Position sensitive <span><math><mi>n</mi></math></span>-on-<span><math><mi>p</mi></math></span> silicon sensors will be utilized in the tracker and in the High Granularity Calorimeter (HGCAL) of the Compact Muon Solenoid (CMS) experiment at High Luminosity Large Hadron Collider (HL-LHC). The detrimental effect of the radiation-induced accumulation of positive net oxide charge on position resolution in <span><math><mi>n</mi></math></span>-on-<span><math><mi>p</mi></math></span> sensors has typically been countered by the application of isolation implants like <span><math><mi>p</mi></math></span>-stop or <span><math><mi>p</mi></math></span>-spray between <span><math><msup><mrow><mi>n</mi></mrow><mrow><mo>+</mo></mrow></msup></math></span>-electrodes. In addition to the positively charged layer inside the oxide and close to the Si/SiO<sub>2</sub>-interface, surface damage introduced by ionizing radiation in SiO<sub>2</sub>-passivated silicon particle detectors includes the accumulation of trapped-oxide-charge and interface traps. A previous study of either n/<span><math><mi>γ</mi></math></span> (mixed field)- or <span><math><mi>γ</mi></math></span>-irradiated Metal-Oxide-Semiconductor (MOS) capacitors showed evidence of substantially higher introduction rates of acceptor- and donor-type deep interface traps (<span><math><msub><mrow><mi>N</mi></mrow><mrow><mtext>it,acc/don</mtext></mrow></msub></math></span>) in mixed-field environment. In this work, an inter-pad and -strip resistance (or resistivity (<span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mtext>int</mtext></mrow></msub></math></span>)) simulation study of <span><math><mi>n</mi></math></span>-on-<span><math><mi>p</mi></math></span> sensors with and without <span><math><mi>p</mi></math></span>-stop isolation implants was conducted for both irradiation types. Higher levels of <span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mtext>int</mtext></mrow></msub></math></span> showed correlation to higher densities of deep <span><math><msub><mrow><mi>N</mi></mrow><mrow><mtext>it,acc/don</mtext></mrow></msub></math></span>, with the inter-pad isolation performance of the mixed-field irradiated sensors becoming independent of the presence of <span><math><mi>p</mi></math></span>-stop implant between the <span><math><msup><mrow><mi>n</mi></mrow><mrow><mo>+</mo></mrow></msup></math></span>-electrodes up to about 100 kGy. The low introduction rates of deep <span><math><msub><mrow><mi>N</mi></mrow><mrow><mtext>it,acc/don</mtext></mrow></msub></math></span> in <span><math><mi>γ</mi></math></span>-irradiated sensors resulted in high sensitivity of <span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mtext>int</mtext></mrow></msub></math></span> to the presence and peak doping of <span><math><mi>p</mi></math></span>-stop above the lowest dose of about 7 kGy in the study. As a consequence of the advantageous influence of radiation-induced accumulation of deep <span><math><msub><mrow><mi>N</mi></mrow><mrow><m
{"title":"Modeling of surface-state induced inter-electrode isolation of n-on-p devices in mixed-field and γ-irradiation environments","authors":"N. Akchurin, T. Peltola","doi":"10.1016/j.nima.2025.170310","DOIUrl":"10.1016/j.nima.2025.170310","url":null,"abstract":"<div><div>Position sensitive <span><math><mi>n</mi></math></span>-on-<span><math><mi>p</mi></math></span> silicon sensors will be utilized in the tracker and in the High Granularity Calorimeter (HGCAL) of the Compact Muon Solenoid (CMS) experiment at High Luminosity Large Hadron Collider (HL-LHC). The detrimental effect of the radiation-induced accumulation of positive net oxide charge on position resolution in <span><math><mi>n</mi></math></span>-on-<span><math><mi>p</mi></math></span> sensors has typically been countered by the application of isolation implants like <span><math><mi>p</mi></math></span>-stop or <span><math><mi>p</mi></math></span>-spray between <span><math><msup><mrow><mi>n</mi></mrow><mrow><mo>+</mo></mrow></msup></math></span>-electrodes. In addition to the positively charged layer inside the oxide and close to the Si/SiO<sub>2</sub>-interface, surface damage introduced by ionizing radiation in SiO<sub>2</sub>-passivated silicon particle detectors includes the accumulation of trapped-oxide-charge and interface traps. A previous study of either n/<span><math><mi>γ</mi></math></span> (mixed field)- or <span><math><mi>γ</mi></math></span>-irradiated Metal-Oxide-Semiconductor (MOS) capacitors showed evidence of substantially higher introduction rates of acceptor- and donor-type deep interface traps (<span><math><msub><mrow><mi>N</mi></mrow><mrow><mtext>it,acc/don</mtext></mrow></msub></math></span>) in mixed-field environment. In this work, an inter-pad and -strip resistance (or resistivity (<span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mtext>int</mtext></mrow></msub></math></span>)) simulation study of <span><math><mi>n</mi></math></span>-on-<span><math><mi>p</mi></math></span> sensors with and without <span><math><mi>p</mi></math></span>-stop isolation implants was conducted for both irradiation types. Higher levels of <span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mtext>int</mtext></mrow></msub></math></span> showed correlation to higher densities of deep <span><math><msub><mrow><mi>N</mi></mrow><mrow><mtext>it,acc/don</mtext></mrow></msub></math></span>, with the inter-pad isolation performance of the mixed-field irradiated sensors becoming independent of the presence of <span><math><mi>p</mi></math></span>-stop implant between the <span><math><msup><mrow><mi>n</mi></mrow><mrow><mo>+</mo></mrow></msup></math></span>-electrodes up to about 100 kGy. The low introduction rates of deep <span><math><msub><mrow><mi>N</mi></mrow><mrow><mtext>it,acc/don</mtext></mrow></msub></math></span> in <span><math><mi>γ</mi></math></span>-irradiated sensors resulted in high sensitivity of <span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mtext>int</mtext></mrow></msub></math></span> to the presence and peak doping of <span><math><mi>p</mi></math></span>-stop above the lowest dose of about 7 kGy in the study. As a consequence of the advantageous influence of radiation-induced accumulation of deep <span><math><msub><mrow><mi>N</mi></mrow><mrow><m","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1074 ","pages":"Article 170310"},"PeriodicalIF":1.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444704","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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