In order to study the possibility of improving the timing performance of the time of flight （TOF） systems, which are made of plastic scintillator counters, and read out by photomultiplier tubes （PMT） with mesh dyn...In order to study the possibility of improving the timing performance of the time of flight （TOF） systems, which are made of plastic scintillator counters, and read out by photomultiplier tubes （PMT） with mesh dynodes and conventional electronics, we have conducted a study using faster PMTs and ultra fast waveform digitizers to read out the plastic scintillators. Different waveform analysis methods are used to calculate the time resolution of such a system. Results are compared with the conventional discriminating method based on a threshold and pulse height. Our tests and analysis show that significant timing performance improvements can be achieved by using this new system.展开更多
Research on a single cell Multi-gap Resistive Plate Chamber (MRPC) was carried out for the Time Of Flight detector (TOF) R and D of the STAR experi- ment. The property of the single chamber was tested with the test be...Research on a single cell Multi-gap Resistive Plate Chamber (MRPC) was carried out for the Time Of Flight detector (TOF) R and D of the STAR experi- ment. The property of the single chamber was tested with the test beam facility T10 at CERN in Geneva. The MRPC was scanned with the test beam to get the efficiency and time resolution at different position of the active area. The HV plateau was also measured. The time resolution is 65 ps which satisfies the requirement of STAR. The working mechanism of the MRPC is also explained.展开更多
A prototype of multi-gap resistive plate chamber (MRPC) modules with 6 gas gaps of 220 μm used for the time-of-flight (TOF) detectors has been developed by STAR TOF group. A tray (TOFr) composed of 28 MRPC modules wa...A prototype of multi-gap resistive plate chamber (MRPC) modules with 6 gas gaps of 220 μm used for the time-of-flight (TOF) detectors has been developed by STAR TOF group. A tray (TOFr) composed of 28 MRPC modules was constructed and operated in STAR for the d+Au collisions and Au+Au collisions during 2003 RHIC and 2004 RHIC run. Results show its time resolution is 85 ps with the average efficiency of 95% and clear identification of K/π up to 1.6 GeV and proton/ K up to 3.0 GeV.展开更多
A GEANT4-based Monte-Carlo （MC） model is developed to study the performance of endcap time- of-flight （ETOF） at BESIII. It＇s found that the multiple scattering effects, mainly from the materials at the MDC endcap...A GEANT4-based Monte-Carlo （MC） model is developed to study the performance of endcap time- of-flight （ETOF） at BESIII. It＇s found that the multiple scattering effects, mainly from the materials at the MDC endcap, can cause multi-hit on the ETOF＇s readout cell and significantly influence the timing property of ETOF. A multi-gap resistive plate chamber （MRPC） with a smaller readout cell structure is more suitable for the ETOF detector due to significantly reduced multi-hit rate （per channel）, from 71.5% for currently-used scintillator-based ETOF to 21.8% or 16.7% for MRPC-based ETOF, depending on the readout pad size used. The timing performance of an MRPC ETOF is also improved. These simulation results suggest and guide an ETOF upgrade effort at BESIII.展开更多
建立了超高效液相色谱-四极杆飞行时间质谱法（UPLC-Q-TOF-MS）对小鼠大脑中的多巴胺（DA）、5-羟色氨（5-HT）、二羟基苯乙酸（DOPAC）和高香草酸（HVA）4种单胺类神经递质的含量进行同时测定。样品以30%乙醇溶液（甲酸调至p H 5.0）...建立了超高效液相色谱-四极杆飞行时间质谱法（UPLC-Q-TOF-MS）对小鼠大脑中的多巴胺（DA）、5-羟色氨（5-HT）、二羟基苯乙酸（DOPAC）和高香草酸（HVA）4种单胺类神经递质的含量进行同时测定。样品以30%乙醇溶液（甲酸调至p H 5.0）匀浆处理后,冷冻离心,过滤。在优化色谱-质谱条件下,采用ESI和APCI复合源,正/负离子扫描方式进行数据采集。4种单胺类神经递质在0.5-1 000μg/L范围内呈良好线性关系,相关系数（r）大于0.999 3,方法的检出限为0.5-5.0μg/L,平均回收率为93.3%-101.8%,相对标准偏差为1.1%-3.3%。该方法具有操作简便、高效快速、回收率良好、灵敏度高、重现性好和准确度高等优点,可用于小鼠脑组织内4种单胺类神经递质的含量测定。展开更多
In order to test the performance of detector prototypes in a laboratory environment, we design and build a large area （90 crux52 cm） test platform for cosmic rays based on a well-designed Multi-gap Resistive Plate C...In order to test the performance of detector prototypes in a laboratory environment, we design and build a large area （90 crux52 cm） test platform for cosmic rays based on a well-designed Multi-gap Resistive Plate Chamber （MRPC） with excellent time resolution and a high detection efficiency for minimum ionizing particles. The time resolution of the MRPC module used is tested to be -80 ps, and the position resolution along the strip is -5 mm, while the position resolution perpendicular to the strip is -12.7 ram. The platform constructed by four MRPC modules can be used for tracking cosmic rays with a spatial resolution of -6.3 mm, and provide a reference time -40 ps.展开更多
基金Supported by National Natural Science Foundation of China(10979003)Main Direction Program of Knowledge Innovation Project of Chinese Academy of Sciences
文摘In order to study the possibility of improving the timing performance of the time of flight （TOF） systems, which are made of plastic scintillator counters, and read out by photomultiplier tubes （PMT） with mesh dynodes and conventional electronics, we have conducted a study using faster PMTs and ultra fast waveform digitizers to read out the plastic scintillators. Different waveform analysis methods are used to calculate the time resolution of such a system. Results are compared with the conventional discriminating method based on a threshold and pulse height. Our tests and analysis show that significant timing performance improvements can be achieved by using this new system.
文摘Research on a single cell Multi-gap Resistive Plate Chamber (MRPC) was carried out for the Time Of Flight detector (TOF) R and D of the STAR experi- ment. The property of the single chamber was tested with the test beam facility T10 at CERN in Geneva. The MRPC was scanned with the test beam to get the efficiency and time resolution at different position of the active area. The HV plateau was also measured. The time resolution is 65 ps which satisfies the requirement of STAR. The working mechanism of the MRPC is also explained.
基金Supported by National Foundation of Natural Sciences of China (10375062)
文摘A prototype of multi-gap resistive plate chamber (MRPC) modules with 6 gas gaps of 220 μm used for the time-of-flight (TOF) detectors has been developed by STAR TOF group. A tray (TOFr) composed of 28 MRPC modules was constructed and operated in STAR for the d+Au collisions and Au+Au collisions during 2003 RHIC and 2004 RHIC run. Results show its time resolution is 85 ps with the average efficiency of 95% and clear identification of K/π up to 1.6 GeV and proton/ K up to 3.0 GeV.
基金Supported by National Natural Science Foundation of China(10979003)
文摘A GEANT4-based Monte-Carlo （MC） model is developed to study the performance of endcap time- of-flight （ETOF） at BESIII. It＇s found that the multiple scattering effects, mainly from the materials at the MDC endcap, can cause multi-hit on the ETOF＇s readout cell and significantly influence the timing property of ETOF. A multi-gap resistive plate chamber （MRPC） with a smaller readout cell structure is more suitable for the ETOF detector due to significantly reduced multi-hit rate （per channel）, from 71.5% for currently-used scintillator-based ETOF to 21.8% or 16.7% for MRPC-based ETOF, depending on the readout pad size used. The timing performance of an MRPC ETOF is also improved. These simulation results suggest and guide an ETOF upgrade effort at BESIII.
文摘建立了超高效液相色谱-四极杆飞行时间质谱法（UPLC-Q-TOF-MS）对小鼠大脑中的多巴胺（DA）、5-羟色氨（5-HT）、二羟基苯乙酸（DOPAC）和高香草酸（HVA）4种单胺类神经递质的含量进行同时测定。样品以30%乙醇溶液（甲酸调至p H 5.0）匀浆处理后,冷冻离心,过滤。在优化色谱-质谱条件下,采用ESI和APCI复合源,正/负离子扫描方式进行数据采集。4种单胺类神经递质在0.5-1 000μg/L范围内呈良好线性关系,相关系数（r）大于0.999 3,方法的检出限为0.5-5.0μg/L,平均回收率为93.3%-101.8%,相对标准偏差为1.1%-3.3%。该方法具有操作简便、高效快速、回收率良好、灵敏度高、重现性好和准确度高等优点,可用于小鼠脑组织内4种单胺类神经递质的含量测定。
基金Supported by National Natural Science Foundation of China(11275196)Strategic Priority Research Program of the Chinese Academy of Sciences(XDA03010100)
文摘In order to test the performance of detector prototypes in a laboratory environment, we design and build a large area （90 crux52 cm） test platform for cosmic rays based on a well-designed Multi-gap Resistive Plate Chamber （MRPC） with excellent time resolution and a high detection efficiency for minimum ionizing particles. The time resolution of the MRPC module used is tested to be -80 ps, and the position resolution along the strip is -5 mm, while the position resolution perpendicular to the strip is -12.7 ram. The platform constructed by four MRPC modules can be used for tracking cosmic rays with a spatial resolution of -6.3 mm, and provide a reference time -40 ps.
