7.62 cm(3英寸)光电倍增管(Photomultiplier Tube,PMT)是江门中微子实验(Jiangmen Underground Neutrino Observatory,JUNO)巨型探测器的重要组成部分,以此构成的一套独立探测系统,承担着独立物理测量、与50.8 cm(20英寸)PMT探测系统相...7.62 cm(3英寸)光电倍增管(Photomultiplier Tube,PMT)是江门中微子实验(Jiangmen Underground Neutrino Observatory,JUNO)巨型探测器的重要组成部分,以此构成的一套独立探测系统,承担着独立物理测量、与50.8 cm(20英寸)PMT探测系统相互检验等重要任务。为提高探测系统的可靠性,使每个7.62 cm PMT供电高压的单通道电流不超过10?A,研究了不同高压电流对7.62 cm PMT探测性能的影响。采用三种高压电流的分压器,对海南展创生产的型号为XP72B20(样管编号为70069)的7.62 cm PMT的性能进行实验测试,包括增益、能量分辨率、峰谷比和阳极输出信号的非线性。结果表明:不同分压电流对7.62 cm PMT性能的影响较小。这个结果为该7.62 cm PMT在JUNO探测器中使用小分压电流的方案提供了重要的实验依据。展开更多
The quality of PMT signals is crucial for large-size and high-precision neutrino experiments, but most of these experiments are affected by the overshoot of PMT signals from the positive HV-single cable scheme. Oversh...The quality of PMT signals is crucial for large-size and high-precision neutrino experiments, but most of these experiments are affected by the overshoot of PMT signals from the positive HV-single cable scheme. Overshoot affects the trigger, dead time and charge measurement from a detector. For the JUNO prototype detector, we have performed a detailed study and calculation on PMT signal overshoot to control the ratio of overshoot to signal amplitude to;%, with no effect on other PMT parameters.展开更多
Objective:To observe the effects of laurocapram and borneol as transdermal penetration enhancers applied to herbal cake-partitioned moxibustion on liver lipids,hormone-sensitive lipase(HSL)and hydroxymethylglutaryl Co...Objective:To observe the effects of laurocapram and borneol as transdermal penetration enhancers applied to herbal cake-partitioned moxibustion on liver lipids,hormone-sensitive lipase(HSL)and hydroxymethylglutaryl CoA(HMG-CoA)reductase in hyperlipidemia rabbits.Methods:Forty New-Zealand rabbits were randomly divided into 5 groups using the random number table method,with 8 rats in each group.Rabbits in the blank group were fed routinely with a normal diet;rabbits in the other groups were fed with high-fat diet for 12 weeks to establish the hyperlipidemia model.Rabbits in the blank and the model groups were not given any intervention.After the model was prepared successfully,rabbits in the non-transdermal penetration enhancer group received herbal cake-partitioned moxibustion without transdermal penetration enhancers;rabbits in the laurocapram group and the borneol group received herbal cake-partitioned moxibustion with laurocapram or borneol respectively.After 4 weeks of treatment,the serum was isolated and enzyme-linked immunosorbent assay(ELISA)was applied for the detection of HSL and HMG-CoA reductase.The liver tissues were isolated,and total cholesterol(TC)and triglycerides(TG)were measured by enzymatic methods.One-step method was applied for high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C)detection,and transmission turbidimetry was for apolipoprotein A1(Apo-A1)and apolipoprotein B(Apo-B)detection.Results:The serum concentrations of the drugs in the laurocapram and the borneol groups were significantly higher than those in the non-transdermal penetration enhancer group(both P<0.05);all drug penetrations in the borneol group were significantly higher than those in the laurocapram group(both P<0.05),except for tanshinoneⅡA.Compared with the non-transdermal penetration enhancer group,the HSL was significantly increased while the HMG-CoA reductase was significantly decreased in the laurocapram and the borneol groups(both P<0.05);between groups,the HSL in the borneol group was significantly higher than that in the laurocapram group(P<0.05).Compared with the blank group,the levels of LDL-C,TG,TC and Apo-B in rabbit liver were significantly increased in the model group(P<0.05);compared with the model group,the levels of LDL-C,TG,TC and Apo-B in the non-transdermal penetration enhancer,the laurocapram,and the borneol groups were significantly decreased(all P<0.05);between groups,the TG and TC in the laurocapram group and the LDL-C,TG,TC and Apo-B in the borneol group were significantly lower than those in the non-transdermal penetration enhancer group(all P<0.05),and the TG,LDL-C and Apo-B in the borneol group were significantly lower than those in the laurocapram group(all P<0.05).Compared with the blank group,the HDL-C and Apo-A1 were significantly decreased in the model group(both P<0.05),while compared with the model group,the HDL-C and Apo-A1 were significantly increased in the non-transdermal penetration enhancer,the laurocapram,and the borneol groups(all P<0.05).Between groups,the Apo-A1 in the laurocapram group,the HDL-C and Apo-A1 in the borneol group were significantly higher than those in the non-transdermal penetration enhancer group(all P<0.05).Conclusion:The application of laurocapram and borneol,as transdermal penetration enhancers,in herbal cake-partitioned moxibustion can promote the penetration of the drugs in the herbal cake,increase the levels of HDL-C and Apo-A1,improve the metabolism of HSL and HMG-CoA reductase,and also simultaneously reduce the levels of TC,TG,LDL-C and Apo-B in the liver.The transdermal penetration enhancement effect of borneol is slightly better than or equivalent to that of laurocapram.展开更多
The neutrino detector of the Jiangmen Underground Neutrino Observatory（JUNO） is designed to use20 kilotons of liquid scintillator and approximately 16000 20 inch photomultipliers（PMTs）.One of the options is to use...The neutrino detector of the Jiangmen Underground Neutrino Observatory（JUNO） is designed to use20 kilotons of liquid scintillator and approximately 16000 20 inch photomultipliers（PMTs）.One of the options is to use the 20 inch R12860 PMT with high quantum efficiency which has recently been developed by Hamamatsu Photonics.The performance of the newly developed PMT preproduction samples is evaluated.The results show that its quantum efficiency is 30%at 400 nm.Its Peak/Valley（P/V） ratio for the single photoelectron is 4.75 and the dark count rate is 27 kHz at the threshold of 3 mV while the gain is at 1 × 10^7.The transit time spread of a single photoelectron is 2.86 ns.Generally the performances of this new 20 inch PMT are improved over the old one of R3600.展开更多
The neutrino detector for the Jiangmen Underground Neutrino Observatory（JUNO） requires a large number of photomultiplier tubes（PMTs）, including 15000 MCP PMTs and 5000 dynode PMTs. The TTS（transit time spread） o...The neutrino detector for the Jiangmen Underground Neutrino Observatory（JUNO） requires a large number of photomultiplier tubes（PMTs）, including 15000 MCP PMTs and 5000 dynode PMTs. The TTS（transit time spread） of the PMTs is very important for vertex and track reconstruction of the neutrinos in the detector. In this paper, we study the TTS of a 20-inch dynode PMT（R12860） from Hamamatsu for different high voltage, light intensity, light spot size and different photocathode regions. The impact from Earth＇s magnetic field is also studied.The results achieved in this paper will be very useful for the JUNO experiment.展开更多
文摘7.62 cm(3英寸)光电倍增管(Photomultiplier Tube,PMT)是江门中微子实验(Jiangmen Underground Neutrino Observatory,JUNO)巨型探测器的重要组成部分,以此构成的一套独立探测系统,承担着独立物理测量、与50.8 cm(20英寸)PMT探测系统相互检验等重要任务。为提高探测系统的可靠性,使每个7.62 cm PMT供电高压的单通道电流不超过10?A,研究了不同高压电流对7.62 cm PMT探测性能的影响。采用三种高压电流的分压器,对海南展创生产的型号为XP72B20(样管编号为70069)的7.62 cm PMT的性能进行实验测试,包括增益、能量分辨率、峰谷比和阳极输出信号的非线性。结果表明:不同分压电流对7.62 cm PMT性能的影响较小。这个结果为该7.62 cm PMT在JUNO探测器中使用小分压电流的方案提供了重要的实验依据。
基金Supported by Strategic Priority Research Program A-JUNO,High Energy Physics Experiment and Detector R&DNational Natural Science Foundation of China
文摘The quality of PMT signals is crucial for large-size and high-precision neutrino experiments, but most of these experiments are affected by the overshoot of PMT signals from the positive HV-single cable scheme. Overshoot affects the trigger, dead time and charge measurement from a detector. For the JUNO prototype detector, we have performed a detailed study and calculation on PMT signal overshoot to control the ratio of overshoot to signal amplitude to;%, with no effect on other PMT parameters.
文摘Objective:To observe the effects of laurocapram and borneol as transdermal penetration enhancers applied to herbal cake-partitioned moxibustion on liver lipids,hormone-sensitive lipase(HSL)and hydroxymethylglutaryl CoA(HMG-CoA)reductase in hyperlipidemia rabbits.Methods:Forty New-Zealand rabbits were randomly divided into 5 groups using the random number table method,with 8 rats in each group.Rabbits in the blank group were fed routinely with a normal diet;rabbits in the other groups were fed with high-fat diet for 12 weeks to establish the hyperlipidemia model.Rabbits in the blank and the model groups were not given any intervention.After the model was prepared successfully,rabbits in the non-transdermal penetration enhancer group received herbal cake-partitioned moxibustion without transdermal penetration enhancers;rabbits in the laurocapram group and the borneol group received herbal cake-partitioned moxibustion with laurocapram or borneol respectively.After 4 weeks of treatment,the serum was isolated and enzyme-linked immunosorbent assay(ELISA)was applied for the detection of HSL and HMG-CoA reductase.The liver tissues were isolated,and total cholesterol(TC)and triglycerides(TG)were measured by enzymatic methods.One-step method was applied for high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C)detection,and transmission turbidimetry was for apolipoprotein A1(Apo-A1)and apolipoprotein B(Apo-B)detection.Results:The serum concentrations of the drugs in the laurocapram and the borneol groups were significantly higher than those in the non-transdermal penetration enhancer group(both P<0.05);all drug penetrations in the borneol group were significantly higher than those in the laurocapram group(both P<0.05),except for tanshinoneⅡA.Compared with the non-transdermal penetration enhancer group,the HSL was significantly increased while the HMG-CoA reductase was significantly decreased in the laurocapram and the borneol groups(both P<0.05);between groups,the HSL in the borneol group was significantly higher than that in the laurocapram group(P<0.05).Compared with the blank group,the levels of LDL-C,TG,TC and Apo-B in rabbit liver were significantly increased in the model group(P<0.05);compared with the model group,the levels of LDL-C,TG,TC and Apo-B in the non-transdermal penetration enhancer,the laurocapram,and the borneol groups were significantly decreased(all P<0.05);between groups,the TG and TC in the laurocapram group and the LDL-C,TG,TC and Apo-B in the borneol group were significantly lower than those in the non-transdermal penetration enhancer group(all P<0.05),and the TG,LDL-C and Apo-B in the borneol group were significantly lower than those in the laurocapram group(all P<0.05).Compared with the blank group,the HDL-C and Apo-A1 were significantly decreased in the model group(both P<0.05),while compared with the model group,the HDL-C and Apo-A1 were significantly increased in the non-transdermal penetration enhancer,the laurocapram,and the borneol groups(all P<0.05).Between groups,the Apo-A1 in the laurocapram group,the HDL-C and Apo-A1 in the borneol group were significantly higher than those in the non-transdermal penetration enhancer group(all P<0.05).Conclusion:The application of laurocapram and borneol,as transdermal penetration enhancers,in herbal cake-partitioned moxibustion can promote the penetration of the drugs in the herbal cake,increase the levels of HDL-C and Apo-A1,improve the metabolism of HSL and HMG-CoA reductase,and also simultaneously reduce the levels of TC,TG,LDL-C and Apo-B in the liver.The transdermal penetration enhancement effect of borneol is slightly better than or equivalent to that of laurocapram.
基金Supported by Strategic Priority Research Program of Chinese Academy of Sciences(X-DA10010200)Key Deployment Project of Chinese Academy of Sciences and CAS Center for Excellence in Particle Physics(CCEPP)
文摘The neutrino detector of the Jiangmen Underground Neutrino Observatory（JUNO） is designed to use20 kilotons of liquid scintillator and approximately 16000 20 inch photomultipliers（PMTs）.One of the options is to use the 20 inch R12860 PMT with high quantum efficiency which has recently been developed by Hamamatsu Photonics.The performance of the newly developed PMT preproduction samples is evaluated.The results show that its quantum efficiency is 30%at 400 nm.Its Peak/Valley（P/V） ratio for the single photoelectron is 4.75 and the dark count rate is 27 kHz at the threshold of 3 mV while the gain is at 1 × 10^7.The transit time spread of a single photoelectron is 2.86 ns.Generally the performances of this new 20 inch PMT are improved over the old one of R3600.
基金Supported by Strategic Priority Research Program of the Chinese Academy of Sciences(XDA10011100)National Natural Science Foundation of China(U1431109,11265003)
文摘The neutrino detector for the Jiangmen Underground Neutrino Observatory（JUNO） requires a large number of photomultiplier tubes（PMTs）, including 15000 MCP PMTs and 5000 dynode PMTs. The TTS（transit time spread） of the PMTs is very important for vertex and track reconstruction of the neutrinos in the detector. In this paper, we study the TTS of a 20-inch dynode PMT（R12860） from Hamamatsu for different high voltage, light intensity, light spot size and different photocathode regions. The impact from Earth＇s magnetic field is also studied.The results achieved in this paper will be very useful for the JUNO experiment.
