微结构探测器是目前国际上气体探测器研究的热点,但普通微结构探测器的性能无法满足核保障等研究领域对能量分辨的要求。为此团队自主研制了一种高能量分辨MicroMegas探测器。通过建立测试系统对探测器进行测试,发现其性能不仅取决于探...微结构探测器是目前国际上气体探测器研究的热点,但普通微结构探测器的性能无法满足核保障等研究领域对能量分辨的要求。为此团队自主研制了一种高能量分辨MicroMegas探测器。通过建立测试系统对探测器进行测试,发现其性能不仅取决于探测器本身的制作工艺,还与系统的使用及测试方法紧密相关。为充分发挥探测器性能,需要对气体探测器性能影响的各方面因素进行测试与分析,建立数据库,优化测试系统和实验条件。在上述研究基础上,利用^(55)Fe放射源在Ar+5%iC_4H_(10)的气体下对原子能院制作的MicroMegas进行能量分辨测试,在5.9 ke V能量下获得能量分辨的平均值为11.7%,与目前国际上微结构探测器的最好水平持平。通过优化测试系统和实验条件,能够获得更加稳定的探测器性能,更容易在核保障、核物理与辐射探测领域推广。展开更多
The PICOSEC Micromegas(MM)is a precise timing gaseous detector based on a Cherenkov radiator coupled with a semi-transparent photocathode and an MM amplifying structure.It features a two-stage amplification process th...The PICOSEC Micromegas(MM)is a precise timing gaseous detector based on a Cherenkov radiator coupled with a semi-transparent photocathode and an MM amplifying structure.It features a two-stage amplification process that leads to a significant deterioration of non-uniformity when scaling up to larger areas.Since the performance of gaseous detectors is highly dependent on the choice of working gas,optimizing the gas mixture offers a promising solution to improve the uniformity performance.This paper addresses these challenges through a combined approach of simulation based on Garfield++and experimental studies.The simulation investigates the properties of different mixing fractions of gas mixtures and their impact on detector performance,including gain uniformity and time resolution.To verify the simulation results,experimental tests were conducted using a multi-channel PICOSEC MM prototype with different gas mixtures.The experimental results are consistent with the findings of the simulation,indicating that a higher concentration of neon significantly improves the detector’s gain uniformity.Furthermore,the influence of gas mixtures on time resolution was explored as a critical performance indicator.The study presented in this paper offers valuable insights for improving uniformity in large-area PICOSEC MM detectors and optimizing overall performance.展开更多
The study of the charge conjugation and parity(CP)violation of hyperon is the precision frontier for probing possible new CP violation sources beyond the standard model(SM).With the large number of quantum entangled h...The study of the charge conjugation and parity(CP)violation of hyperon is the precision frontier for probing possible new CP violation sources beyond the standard model(SM).With the large number of quantum entangled hyperonantihyperon pairs to be produced at Super Tau-Charm Facility(STCF),the CP asymmetry of hyperon is expected to be tested with a statistical sensitivity of 10^(−4) or even better.To cope with the statistical precision,the systematic effects from various aspects are critical and need to be studied in detail.In this paper,the sensitivity effects on the CP violation parameters associated with the detector resolution,including those of the position and momentum,are studied and discussed in detail.The results provide valuable guidance for the design of STCF detector.展开更多
The Wilson coefficients of the standard model effective field theory are subject to a series of positivity bounds.It has been shown that while the positivity part of the ultraviolet(UV)partial wave unitarity leads to ...The Wilson coefficients of the standard model effective field theory are subject to a series of positivity bounds.It has been shown that while the positivity part of the ultraviolet(UV)partial wave unitarity leads to the Wilson coefficients living in a convex cone,further including the nonpositivity part caps the cone from above.For Higgs scattering,a capped positivity cone was obtained using a simplified,linear unitarity condition without utilizing the full internal symmetries of Higgs scattering.Here,we further implement stronger nonlinear unitarity conditions from the UV,which generically gives rise to better bounds.We show that,for the Higgs case in particular,while the nonlinear unitarity conditions per se do not enhance the bounds,the fuller use of the internal symmetries do shrink the capped positivity cone significantly.展开更多
文摘微结构探测器是目前国际上气体探测器研究的热点,但普通微结构探测器的性能无法满足核保障等研究领域对能量分辨的要求。为此团队自主研制了一种高能量分辨MicroMegas探测器。通过建立测试系统对探测器进行测试,发现其性能不仅取决于探测器本身的制作工艺,还与系统的使用及测试方法紧密相关。为充分发挥探测器性能,需要对气体探测器性能影响的各方面因素进行测试与分析,建立数据库,优化测试系统和实验条件。在上述研究基础上,利用^(55)Fe放射源在Ar+5%iC_4H_(10)的气体下对原子能院制作的MicroMegas进行能量分辨测试,在5.9 ke V能量下获得能量分辨的平均值为11.7%,与目前国际上微结构探测器的最好水平持平。通过优化测试系统和实验条件,能够获得更加稳定的探测器性能,更容易在核保障、核物理与辐射探测领域推广。
基金supported by the National Natural Science Foundation of China(12125505).
文摘The PICOSEC Micromegas(MM)is a precise timing gaseous detector based on a Cherenkov radiator coupled with a semi-transparent photocathode and an MM amplifying structure.It features a two-stage amplification process that leads to a significant deterioration of non-uniformity when scaling up to larger areas.Since the performance of gaseous detectors is highly dependent on the choice of working gas,optimizing the gas mixture offers a promising solution to improve the uniformity performance.This paper addresses these challenges through a combined approach of simulation based on Garfield++and experimental studies.The simulation investigates the properties of different mixing fractions of gas mixtures and their impact on detector performance,including gain uniformity and time resolution.To verify the simulation results,experimental tests were conducted using a multi-channel PICOSEC MM prototype with different gas mixtures.The experimental results are consistent with the findings of the simulation,indicating that a higher concentration of neon significantly improves the detector’s gain uniformity.Furthermore,the influence of gas mixtures on time resolution was explored as a critical performance indicator.The study presented in this paper offers valuable insights for improving uniformity in large-area PICOSEC MM detectors and optimizing overall performance.
基金supported by the National Key R&D Program of China(2022YFA1602200)the International Partnership Program of the Chinese Academy of Sciences(211134KYSB20200057).
文摘The study of the charge conjugation and parity(CP)violation of hyperon is the precision frontier for probing possible new CP violation sources beyond the standard model(SM).With the large number of quantum entangled hyperonantihyperon pairs to be produced at Super Tau-Charm Facility(STCF),the CP asymmetry of hyperon is expected to be tested with a statistical sensitivity of 10^(−4) or even better.To cope with the statistical precision,the systematic effects from various aspects are critical and need to be studied in detail.In this paper,the sensitivity effects on the CP violation parameters associated with the detector resolution,including those of the position and momentum,are studied and discussed in detail.The results provide valuable guidance for the design of STCF detector.
基金supported by the Fundamental Research Funds for the Central Universities(WK2030000036)the National Natural Science Foundation of China(12075233).
文摘The Wilson coefficients of the standard model effective field theory are subject to a series of positivity bounds.It has been shown that while the positivity part of the ultraviolet(UV)partial wave unitarity leads to the Wilson coefficients living in a convex cone,further including the nonpositivity part caps the cone from above.For Higgs scattering,a capped positivity cone was obtained using a simplified,linear unitarity condition without utilizing the full internal symmetries of Higgs scattering.Here,we further implement stronger nonlinear unitarity conditions from the UV,which generically gives rise to better bounds.We show that,for the Higgs case in particular,while the nonlinear unitarity conditions per se do not enhance the bounds,the fuller use of the internal symmetries do shrink the capped positivity cone significantly.
