Abstract:

A method of spontaneous deposition of ²¹⁰Po on a silver disc was used to prepare the standard plane source in a ²¹⁰Pb solution. The prepared source was measured by an alpha spectrometer. There was a unique alpha peak of 5.304 MeV with a full width at half maximum of 23.92 keV in the measured spectrum. A plateau length of about 1000 V was given in the plateau curve measued with a multi-wire proportional counter. The determined surface emission rate was 2.565 ×10⁴ min^-1 at JAN.  3RD , 2019, with the extended uncertainty of 2.7% (k=2). Some MPC9604 gas-flow low background gross alpha and gross beta counters were used to test the source according to the verification regulation JJG 1100-2014. All the α detection efficiencies were not less than 77%, the repeatability within 1.5% and the α interference to β channel not greater than 2.5%. It’s showed that the prepared source was in good quality and performance to meet the calibration of gas-flow low background gross alpha and gross beta counters.

Key words: ²¹⁰Po, spontaneous deposition, surface emission rate, energy resolution

摘要：

采用自沉积法从²¹⁰Po溶液中制备了²¹⁰Po平面源，用α谱仪测量该平面源，测量谱中只有一个5.304 MeV α能峰，能量分辨率为23.92 keV。用2πα、2πβ表面发射率标准装置测量该平面源的坪曲线，坪区为0.8~1.8 kV，坪长为1 000 V，测定的表面发射率为2.565×10⁴ min^-1（参考日期2019年1月3日），扩展不确定度为2.7%（k=2）。按JJG 1100-2014检定规程用MPC9604型流气式低本底α、β测量仪测定该源，探测效率不低于77%，重复性在1.5%以内，α对β道串道比在2.5%以内。该方法操作简便，制备的²¹⁰Po平面标准源性能满足工作需求。

关键词: ²¹⁰Po, 自沉积, 表面发射率, 能量分辨率