多丝正比计数器工作气体压强变化对α、β表面粒子发射率测量的影响
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摘要
为了研究工作气体气压变化对α和β源表面发射率绝对测量的影响,在α、β表面粒子发射率基准装置上,通过改变多丝正比计数器工作气体压强,对大面积α平面源241Am、β平面源204Tl和90Sr/90Y的表面粒子发射率进行了绝对测量,并通过阈值外推方法对低能信号引起的漏计数率进行修正。结果表明,当工作气体压强在50～180 k Pa气压范围内变化时,不同气压条件下的α、β表面粒子发射率测量结果在实验不确定度范围内相一致。基于Geant4程序包对探测器结构进行建模,Monte Carlo方法给出的模拟结果得出的结论与实验结果相符。
In order to the investigation of the absolute measurements for α and β surface emission rates due to the working gas pressure variations in China NIM by using α and β multi-wire proportional counter. The surface emission rates measurement of plane sources241Am、204Tl and90Sr/90 Y is measured respectively by changing working gas pressure in multiwire proportional counter. The counting rate loss of small pules is corrected by the threshold extrapolation method. The results show that by taking in to account the counting loss of small pules,there is no significant difference observed and all of the measured emission rates are consistent in the range of the evaluated uncertainty within the range of 50 k Pa to 180 k Pa atmosphere. Monte Carlo simulations based on Geant4 code were also carried out to support our results. The results obtained by the Monte Carlo method are in agreement with the experimental results.
In order to the investigation of the absolute measurements for α and β surface emission rates due to the working gas pressure variations in China NIM by using α and β multi-wire proportional counter. The surface emission rates measurement of plane sources241Am、204Tl and90Sr/90 Y is measured respectively by changing working gas pressure in multiwire proportional counter. The counting rate loss of small pules is corrected by the threshold extrapolation method. The results show that by taking in to account the counting loss of small pules,there is no significant difference observed and all of the measured emission rates are consistent in the range of the evaluated uncertainty within the range of 50 k Pa to 180 k Pa atmosphere. Monte Carlo simulations based on Geant4 code were also carried out to support our results. The results obtained by the Monte Carlo method are in agreement with the experimental results.
引文
[1] Sullivan P,Ghushchyan V H,Slejko J F. Methods for primary standardization of activity[J]. Metrologia,2007,44:S17-S26.
[2]李泽西,贺海江,梁珺成,等. 2!α、2!β粒子发射率现场校准装置的建立[J].计量学报,2017,38(1):117-122.Li Z X,He H J,Liang J C,et al. The Establishment of the On-site Calibration Device for 2!αand 2!βParticle Emission Rate Measurement[J]. Acta Metrologica Sinica,2017,38(1):117-122.
[3] Yunoki A,Hino Y. APMP comparison of measurement of surface emission rate of 36Cl large area source(APMP. RI(II)-K2. Cl-36)[J]. Applied Radiation&Isotopes,2012,70(9):1831-1835.
[4] Hutchinson J M R,Bright S J. The NBS large-area alpha particle counting systems[J]. Res Natl Bur Stand,1987,92(5):311-323.
[5] King L E,Hutchinson J M R,Unterweger M P. A new large-area 2!,proportional counting system at NIST[J]. Applied Radiation&Isotopes,2008,66(6-7):877-880.
[6] Wuu J L,Yuan M C,Su S H,et al. The alpha and beta emitter measurement system in INER Institute of Nuclear Energy Research[J]. Applied Radiation&Isotopes Including Data Instrumentation&Methods for Use in Agriculture Industry&Medicine,2002,56(1):261-264.
[7]李奇,常永福,解峰,等.内充气正比计数管系统绝对测量87Kr放射性活度浓度[J].原子能科学技术,2006,40(4):443-446.Li Q,Chang Y F,Xie F,et al. Absolute Measurement of Activity Concentration of87Kr by Using Internal Gas Proportional Counting[J]. Atomic Energy Science and Technology,2006,40(4):443-446.
[8]骆志平,庞洪超,刘阳,等.大面积气体闪烁正比计数器的研制及性能测试[J].原子能科学技术,2016,50(10):1871-1874.Luo Z P,Pang H C,Liu Y,et al. Development and performance testing of large surface gas scintillation proportional counter[J]. Atomic Energy Science and Technology,2016,50(10):1871-1874.
[9] Liang J C,Li Q,Liu J C, et al. The absolute measurement of 2!αand 2!βparticle emission rate[J]. Acta Metrologica Sinica,2016,37(2):209-213.
[10] Tu Z,Song K Z,Zhang M,et al. A new digital pulse processing method for 2!αand 2!βemitter measurement[J]. Nucl Sci Technol,2016,27(6):137-143.
[11] Kumar M, Gandhi S S, Nuwad J, et al. An electrochemical pathway to prepare circular planar 90Sr/90 Y sources for the calibration of surface contamination monitors[J]. Journal of Radioanalytical&Nuclear Chemistry,2014,302(1):709-719.
[12] Unterweger M P,Felice P De. Uncertainties in surface emission rate measurements[J]. Metrologia,2015,52(3):S165-S171.
[13]吴治华.原子核物理实验方法[M].北京:原子能出版社,1981.
[2]李泽西,贺海江,梁珺成,等. 2!α、2!β粒子发射率现场校准装置的建立[J].计量学报,2017,38(1):117-122.Li Z X,He H J,Liang J C,et al. The Establishment of the On-site Calibration Device for 2!αand 2!βParticle Emission Rate Measurement[J]. Acta Metrologica Sinica,2017,38(1):117-122.
[3] Yunoki A,Hino Y. APMP comparison of measurement of surface emission rate of 36Cl large area source(APMP. RI(II)-K2. Cl-36)[J]. Applied Radiation&Isotopes,2012,70(9):1831-1835.
[4] Hutchinson J M R,Bright S J. The NBS large-area alpha particle counting systems[J]. Res Natl Bur Stand,1987,92(5):311-323.
[5] King L E,Hutchinson J M R,Unterweger M P. A new large-area 2!,proportional counting system at NIST[J]. Applied Radiation&Isotopes,2008,66(6-7):877-880.
[6] Wuu J L,Yuan M C,Su S H,et al. The alpha and beta emitter measurement system in INER Institute of Nuclear Energy Research[J]. Applied Radiation&Isotopes Including Data Instrumentation&Methods for Use in Agriculture Industry&Medicine,2002,56(1):261-264.
[7]李奇,常永福,解峰,等.内充气正比计数管系统绝对测量87Kr放射性活度浓度[J].原子能科学技术,2006,40(4):443-446.Li Q,Chang Y F,Xie F,et al. Absolute Measurement of Activity Concentration of87Kr by Using Internal Gas Proportional Counting[J]. Atomic Energy Science and Technology,2006,40(4):443-446.
[8]骆志平,庞洪超,刘阳,等.大面积气体闪烁正比计数器的研制及性能测试[J].原子能科学技术,2016,50(10):1871-1874.Luo Z P,Pang H C,Liu Y,et al. Development and performance testing of large surface gas scintillation proportional counter[J]. Atomic Energy Science and Technology,2016,50(10):1871-1874.
[9] Liang J C,Li Q,Liu J C, et al. The absolute measurement of 2!αand 2!βparticle emission rate[J]. Acta Metrologica Sinica,2016,37(2):209-213.
[10] Tu Z,Song K Z,Zhang M,et al. A new digital pulse processing method for 2!αand 2!βemitter measurement[J]. Nucl Sci Technol,2016,27(6):137-143.
[11] Kumar M, Gandhi S S, Nuwad J, et al. An electrochemical pathway to prepare circular planar 90Sr/90 Y sources for the calibration of surface contamination monitors[J]. Journal of Radioanalytical&Nuclear Chemistry,2014,302(1):709-719.
[12] Unterweger M P,Felice P De. Uncertainties in surface emission rate measurements[J]. Metrologia,2015,52(3):S165-S171.
[13]吴治华.原子核物理实验方法[M].北京:原子能出版社,1981.