基于指数法评估激光量热仪吸收测量不确定度

Evaluation of absorption measurement uncertainty of laser calorimeter by exponential method

为了掌握熔石英样品在紫外波段的吸收特性,研究了精确评估激光量热仪测量不确定度的方法。介绍了激光量热仪的吸收测量原理,选用指数法对吸收测量数据进行了拟合;通过分析各吸收率测量结果的影响分量,建立了测量不确定度评估模型;对各输入量的估计值以及估计值的标准不确定度逐一进行计算,并对影响吸收率测量结果的拟合计算参数A、γ进行了修正。考虑背景温度漂移对被测样品温度测量的影响,利用Matlab编程分析了线性、非线性温度漂移对吸收计算结果的影响,获得其相对标准不确定度及相对扩展不确定度分别为2.6%和5.2%。最后,更换熔石英基底并进行多次吸收测量,计算了吸收率10次测量结果平均值的相对标准不确定度为2.3%,相对扩展不确定度为4.6%,与评估结果基本相同。

To better understand the absorption characters of fused silica in ultra-violet wavelength, a method to evaluate accurately the measurement uncertainty of a laser calorimeter was explored. The measurement principle of laser calorimeter was introduced firstly, and then the measured absorption data were fitted by the exponential method. After analysis of different effect factors on measuring results, a model for the measurement uncertainty was established, the estimated value and its standard uncertainty of the each input were calculated and the fitting calculation parameters A,γ effecting on absorption measuring results were corrected. By taking the influence of background temperature drift on the measurement uncertainty into account, the influences of linear and nonlinear temperature drifts on the absorption result were simulated by Matlab. The results show that the relative standard uncertainty and relative extended uncertainty of the laser calorimeter are 2.6% and 5.2 % respectively. Finally, the absorption measurement was performed for several times by replacing fused silica substrates, and the average values of absorption measuring results for 10 times show the relative standard uncertainty to be 2.3 % and relative extended uncertainty to be 4.6 %, which are conform to that of evaluated results well.