As interest in double perovskites is growing,especially in applications like photovoltaic devices,understanding their mechanical properties is vital for device durability.Despite extensive exploration of structure and...As interest in double perovskites is growing,especially in applications like photovoltaic devices,understanding their mechanical properties is vital for device durability.Despite extensive exploration of structure and optical properties,research on mechanical aspects is limited.This article builds a vacancyordered double perovskite model,employing first-principles calculations to analyze mechanical,bonding,electronic,and optical properties.Results show Cs_(2)Hfl_(6),Cs_(2)SnBr_(6),Cs_(2)SnI_(6),and Cs_(2)PtBr_(6)have Young's moduli below 13 GPa,indicating flexibility.Geometric parameters explain flexibility variations with the changes of B and X site composition.Bonding characteristic exploration reveals the influence of B and X site electronegativity on mechanical strength.Cs_(2)SnBr_(6)and Cs_(2)PtBr_(6)are suitable for solar cells,while Cs_(2)HfI_(6)and Cs_(2)TiCl_(6)show potential for semi-transparent solar cells.Optical property calculations highlight the high light absorption coefficients of up to 3.5×10^(5) cm^(-1)for Cs_(2)HfI_(6)and Cs_(2)TiCl_(6).Solar cell simulation shows Cs_(2)PtBr_(6)achieves 22.4%of conversion effciency.Cs_(2)ZrCl_(6)holds promise for ionizing radiation detection with its 3.68 eV bandgap and high absorption coefficient.Vacancy-ordered double perovskites offer superior flexibility,providing valuable insights for designing stable and flexible devices.This understanding enhances the development of functional devices based on these perovskites,especially for applications requiring high stability and flexibility.展开更多
In recent years, cooling technology for liquid xenon(LXe) detectors has advanced driven by the development of dark matter(DM) detectors with target mass in the 100–1000 kg range. The next generation of DM detectors b...In recent years, cooling technology for liquid xenon(LXe) detectors has advanced driven by the development of dark matter(DM) detectors with target mass in the 100–1000 kg range. The next generation of DM detectors based on LXe will be in the 50,000 kg(50 t)range requiring more than 1 k W of cooling power. Most of the prior cooling methods become impractical at this level.For cooling a 50 t scale LXe detector, a method is proposed in which liquid nitrogen(LN2) in a small local reservoir cools the xenon gas via a cold finger. The cold finger incorporates a heating unit to provide temperature regulation. The proposed cooling method is simple, reliable, and suitable for the required long-term operation for a rare event search. The device can be easily integrated into present cooling systems, for example the ‘‘Cooling Bus’ ’employed for the Panda X I and II experiments. It is still possible to cool indirectly with no part of the cooling or temperature control system getting in direct contact with the clean xenon in the detector. Also, the cooling device can be mounted at a large distance, i.e., the detector is cooled remotely from a distance of 5–10 m. The method was tested in a laboratory setup at Columbia University to carry out different measurements with a small LXe detector and behaved exactly as predicted.展开更多
Introduction Pixel detectors fabricated with the silicon-on-insulator(SOI)technology suffered from the digital pickup,due to the capacitive coupling between the sensing electrode and the in-pixel circuit.In order to t...Introduction Pixel detectors fabricated with the silicon-on-insulator(SOI)technology suffered from the digital pickup,due to the capacitive coupling between the sensing electrode and the in-pixel circuit.In order to tackle this issue,an advanced process called double SOI has been developed.A prototype chip CPIXTEG3b adopting this new process was designed and characterized.While optimization concerning the double-SOI design and testing of the single pixel were already presented in a separate publication,this paper focuses on its noise performance of the full matrix and X-ray detection utilizing a synchrotron photon beam.Methods Equivalent noise charge(ENC)of the full pixel matrix was measured with electrical pulse tests.The threshold dispersion was minimized by the DAC tuning in each individual pixel.As a photon-counting X-ray imager,noise count accumulated up to 1 h was measured.Detection efficiency was measured with a micro-focused beam as well as a flat field generated by the X-ray scattering on a glassy carbon at the KEK PF beam line 14A.Results The typical ENC is 52 e−and the sigma of threshold dispersion is 10 e−over the full matrix.A merit of“zero”noise count is also demonstrated,which is consistent with the low ENC.The prototype chip has been tested with microbeam and used to measure the beam profile to be with a full width of 50µm at 2.4%of the maximum height.Both sensor depletion and charge sharing between neighboring pixels have been carefully characterized,providing insights for further development.The homogeneity of response to X-ray photons has been demonstrated in the flat field test.This work has drawn a final conclusion to the solution of digital pickup issue and opened a promising prospect in low-noise and high-resolution X-ray imaging.展开更多
基于兰州重离子研究装置冷却储存环(HIRFL-CSR)发展了等时性质谱术(Isochronous mass spectrometry,IMS),高精度测量了一批短寿命原子核的质量并研究了核结构和核天体领域的相关物理问题。本文综述了IMS实验的原理和步骤,重点介绍了目...基于兰州重离子研究装置冷却储存环(HIRFL-CSR)发展了等时性质谱术(Isochronous mass spectrometry,IMS),高精度测量了一批短寿命原子核的质量并研究了核结构和核天体领域的相关物理问题。本文综述了IMS实验的原理和步骤,重点介绍了目前正在发展的双TOF探测器谱仪。利用双TOF质量谱仪在测量离子回旋周期的同时测量了离子的速度,用来修正实验结果,可以在很宽的动量接收度内实现高质量分辨,并消除离子动量分散带来的系统误差。双TOF等时性质谱术是全新的概念,需要针对性开发相关实验技术。我们建立了基于CSRe的模拟平台,研制了高性能TOF探测器并安装在CSRe直线段,进行了在线束流测试,发展了新的束流光学设置并进行优化,开发了实验数据处理方法并在做进一步优化,并对下一步工作进行了展望。展开更多
基金supported by the National Natural Science Foundation of China(62305261,62305262)the Natural Science Foundation of Shaanxi Province(2024JC-YBMS-021,2024JC-YBMS-788,2023-JC-YB-065,2023-JC-QN-0693,2022JQ-652)+1 种基金the Xi’an Science and Technology Bureau of University Service Enterprise Project(23GXFW0043)the Cross disciplinary Research and Cultivation Project of Xi’an University of Architecture and Technology(2023JCPY-17)。
文摘As interest in double perovskites is growing,especially in applications like photovoltaic devices,understanding their mechanical properties is vital for device durability.Despite extensive exploration of structure and optical properties,research on mechanical aspects is limited.This article builds a vacancyordered double perovskite model,employing first-principles calculations to analyze mechanical,bonding,electronic,and optical properties.Results show Cs_(2)Hfl_(6),Cs_(2)SnBr_(6),Cs_(2)SnI_(6),and Cs_(2)PtBr_(6)have Young's moduli below 13 GPa,indicating flexibility.Geometric parameters explain flexibility variations with the changes of B and X site composition.Bonding characteristic exploration reveals the influence of B and X site electronegativity on mechanical strength.Cs_(2)SnBr_(6)and Cs_(2)PtBr_(6)are suitable for solar cells,while Cs_(2)HfI_(6)and Cs_(2)TiCl_(6)show potential for semi-transparent solar cells.Optical property calculations highlight the high light absorption coefficients of up to 3.5×10^(5) cm^(-1)for Cs_(2)HfI_(6)and Cs_(2)TiCl_(6).Solar cell simulation shows Cs_(2)PtBr_(6)achieves 22.4%of conversion effciency.Cs_(2)ZrCl_(6)holds promise for ionizing radiation detection with its 3.68 eV bandgap and high absorption coefficient.Vacancy-ordered double perovskites offer superior flexibility,providing valuable insights for designing stable and flexible devices.This understanding enhances the development of functional devices based on these perovskites,especially for applications requiring high stability and flexibility.
基金the Ministry of Science and Technology of China(No.2016YFA0400301)the grants for the XENON Dark Matter Project。
文摘In recent years, cooling technology for liquid xenon(LXe) detectors has advanced driven by the development of dark matter(DM) detectors with target mass in the 100–1000 kg range. The next generation of DM detectors based on LXe will be in the 50,000 kg(50 t)range requiring more than 1 k W of cooling power. Most of the prior cooling methods become impractical at this level.For cooling a 50 t scale LXe detector, a method is proposed in which liquid nitrogen(LN2) in a small local reservoir cools the xenon gas via a cold finger. The cold finger incorporates a heating unit to provide temperature regulation. The proposed cooling method is simple, reliable, and suitable for the required long-term operation for a rare event search. The device can be easily integrated into present cooling systems, for example the ‘‘Cooling Bus’ ’employed for the Panda X I and II experiments. It is still possible to cool indirectly with no part of the cooling or temperature control system getting in direct contact with the clean xenon in the detector. Also, the cooling device can be mounted at a large distance, i.e., the detector is cooled remotely from a distance of 5–10 m. The method was tested in a laboratory setup at Columbia University to carry out different measurements with a small LXe detector and behaved exactly as predicted.
基金This work is supported by the National Nature Science Foundation of China,Grant Nos.11375226 and 11575220.
文摘Introduction Pixel detectors fabricated with the silicon-on-insulator(SOI)technology suffered from the digital pickup,due to the capacitive coupling between the sensing electrode and the in-pixel circuit.In order to tackle this issue,an advanced process called double SOI has been developed.A prototype chip CPIXTEG3b adopting this new process was designed and characterized.While optimization concerning the double-SOI design and testing of the single pixel were already presented in a separate publication,this paper focuses on its noise performance of the full matrix and X-ray detection utilizing a synchrotron photon beam.Methods Equivalent noise charge(ENC)of the full pixel matrix was measured with electrical pulse tests.The threshold dispersion was minimized by the DAC tuning in each individual pixel.As a photon-counting X-ray imager,noise count accumulated up to 1 h was measured.Detection efficiency was measured with a micro-focused beam as well as a flat field generated by the X-ray scattering on a glassy carbon at the KEK PF beam line 14A.Results The typical ENC is 52 e−and the sigma of threshold dispersion is 10 e−over the full matrix.A merit of“zero”noise count is also demonstrated,which is consistent with the low ENC.The prototype chip has been tested with microbeam and used to measure the beam profile to be with a full width of 50µm at 2.4%of the maximum height.Both sensor depletion and charge sharing between neighboring pixels have been carefully characterized,providing insights for further development.The homogeneity of response to X-ray photons has been demonstrated in the flat field test.This work has drawn a final conclusion to the solution of digital pickup issue and opened a promising prospect in low-noise and high-resolution X-ray imaging.
文摘基于兰州重离子研究装置冷却储存环(HIRFL-CSR)发展了等时性质谱术(Isochronous mass spectrometry,IMS),高精度测量了一批短寿命原子核的质量并研究了核结构和核天体领域的相关物理问题。本文综述了IMS实验的原理和步骤,重点介绍了目前正在发展的双TOF探测器谱仪。利用双TOF质量谱仪在测量离子回旋周期的同时测量了离子的速度,用来修正实验结果,可以在很宽的动量接收度内实现高质量分辨,并消除离子动量分散带来的系统误差。双TOF等时性质谱术是全新的概念,需要针对性开发相关实验技术。我们建立了基于CSRe的模拟平台,研制了高性能TOF探测器并安装在CSRe直线段,进行了在线束流测试,发展了新的束流光学设置并进行优化,开发了实验数据处理方法并在做进一步优化,并对下一步工作进行了展望。
