Study About Calibrating Radon Detector With Canned Radon

[Objective]:In order to meet the need of the radon detector's calibration and checking during verification interval,developing a method to calibrate the radon detector with radon in a can.This measurement is based on the principle of measuring radon and the law of radon decay,and developed a dynamic and standard material----radon-in-can,which can effectively overcome the lack and shortcomings of the standard radiumsource,achieving the quality control of the radon detector.[Methods]:Experimental material:HD-3 type multifunctional radon chamber?the Jiangsu provincial quality and technical supervision of radon measuring instrument measuring station radon measurement standards,Measurement Standard No.[2005]province standard certification No.127th?,FD-125 analyzer of thorium radonand RAD7electronic Emanometer;related parts experiment:rotor flowmeter,constant flow pump,dryer and valve;desiccant used in experiment is silica gel.Radon effective decay constant?_etest for radon cylinders:Repeat the test with radon for the same radon tank for 5 times,for 7 to 8 days each time,for practical use with radon tanks?Day 2 to Day 8?),Select the data between each measurement 24h¹68h to calculate the?_e of the radon tank,to get the range of the?_e.Comparison of radon tank and standard radon chamber:To calibrate 2 radon measuring instruments RAD7 with standard radon chamber and canned radon respectively,and calculating the volume activity response and repeatability of RAD7.Analyze the comparative results.[Results]:1?The 5 test results show that the range of ?_e of the canned radon is?8.83×10-3⁹.55×10-3?h^-1,the average value is 9.13×10-3h^-1,repeatability is 3.3%,the relative error is4.5%,and the fitting of the R² is greater than.0.993.2?Radon detector numbered by 2576,calibrated with the standard radon chamber scale,its volumetric activity response is 0.905,repeatability is 2.7%;calibrated with radon tank scale,its volume activity response is0.909,repeatability range of 2.8%⁶.2%,the relative inherent error is-3.6%;The relative error between the volumetric activity response of two scale methods is 0.4%.Radon detector numbered by 2314,calibrated with the standard radon chamber scale,its volumetric activity response is0.903,repeatability is 3.4%;calibrated with radon tank scale,its volume activity response is 0.895,repeatability range of 3.4%⁶.1%,the relative inherent error is 3.8%;The relative error between the volumetric activity response of two scale methods is0.9%.[Conclusion]:It is feasible to calibrate radon emanometer with canned radon.It can not only satisfy the“verification regulation of radonmeasurement”?JJG825-2013?,which means that the relative extended uncertainty of dynamic stability of the radon concentration of the radon source is less than 10%?k=2?;but also ensure scale instrument repeatability of not more than 15%,relative to the inherent error of not more than±20%,compared with standard radon chamber,when it is used to calibrate Radon detectors.