^(95)Zr水样的测量方法研究

A study on measurement of water sample contains zirconium - 95

采用BH12 2 4型能谱仪测量了95 Zr水样的能谱图 ,并对其测量的重复性、样品量和活度对测量结果的影响等进行了测定分析 ,确定了相应的校正曲线。结果显示 :1) 95 Zr能谱有三个峰 ,选取S3峰 (2 40 30 0能谱道 )作为样品活度的测量道较为合适 ;2 )测量时间对测样的计数率没有影响 ;样品量对测样的重复性影响较小 ;3)随着样品量的增加 ,同一活度样品的测量值呈下降趋势 ,应进行该项目的校正 ,校正曲线为Y1 =1.0 183- 0 .0 0 70X1 (X1 为测样的样品量 g) ;4)仪器死时间引起的漏计数不容忽视 ,对测量结果应进行死时间校正 ,其校正系数 (% )Y2 =10 1.33- 0 .0 2 2 6X2 (X2 为测样的计数率cps) ;5 )样品活度对测量的重复性有影响 ,当测样的活度过小时 ,其重复性就较差 ;为获得较好的测量重复性 (<1% ) ,活度以大于2 0 0Bq为宜。

The energy spectrum curve of 95 Zr water samples was measured by using BH1224 energy spectrometer, and the influence of its metrical repeatability, the weight of samples and radioactivity on the results was determined and analyzed, then concluded the corresponding calibration curve. The results showed: 1) The energy spectrum of 95 Zr had three apices, it's rather suitable to select the apex of S3 (energy spectrum path:240 300) as the measurement path; 2) The time of measurement had no effects on the count ratio of measuring samples; the weight of samples had less influence on the measuring repeatability; 3) With increasing samples' weight, the measuring values of the samples with same radioactivity was downtrend, which showed that the values should be calibrated. The calibration curve was as follows: Y 1=1.0183-0.0070X 1( X 1 was samples weight, unit is g); 4) The leaked counts caused by the dead time should not be neglected and the measuring results should be calibrated. The calibration factor (%) was as follows: Y 2=101.33-0.0226X 2 (X 2 was the counts per second, unit is cps); 5) When samples radioactivity was too low, the repeatability was comparatively bad, which illustrated that samples radioactivity affected metrical repeatability. Therefore in order to obtain better metrical repeatability (<1%), the radioactivity should exceed 200Bq.