水流吸收型高能激光能量计溯源方法及其溯源体系研究

提出了一种利用电加热丝作为校准源的高能激光能量计校准方法,将水流从吸收腔前端导入至加热容器,在加热后流入吸收腔。通过精确计量水流吸收的热能并与能量计测量结果进行比较,达到对高能激光能量计校准的目的。研究表明校准系统的热交换模型与吸收腔内的热交换模型一致,均经历了储能和功率平衡两个阶段。水流及相变气体的散射效应对测量结果的影响较小,经过修正后可以忽略其影响。通过深入分析各个环节的测量不确定度表明,残留能量和流量变化对测量不确定度的影响最显著,增加水箱的容积可以有效降低残留能量对测量不确定度的影响。在对各个环节的影响修正后估算出系统的测量不确定度约为4.8%(k=2),被校高能激光能量计校准后的测量结果与其他类型的参考高能激光能量计进行比对,两者具有很好的一致性,修正因子仅为1.006,标准偏差为1.4%。

Calibration methods and calibration systems of water-absorption-type high energy laser energy meters

Water-absorption-type high energy laser energy meters are widely applied to the energy measurement of high energy lasers for their high efficiency in the heat exchange. However, its calibration is a considerable difficulty for the absence of high power standard lasers. A calibration method for the high energy laser energy meter with the electric heating wires was introduced, and water was led into a heating container at the entrance of the absorption cavity. Then it is heated before flowing into the absorption cavity. The energy absorbed by the water flow was estimated and compared with the one measured by the energy meter to calibrate the energy meter. The conclusion can be drawn that the heat exchange modal of the calibration system is just the same with the one in the absorption cavity. They include two stages, in the first stage energy is stored and in the second stage the power reaches equivalent. The scattering of the flow and the gas has few effects on the measurement results, and the effects can be ignored after the results are calibrated. It can be concluded that the remaining energy and the flow rate have great effects on the measurement results and the effects caused by remaining energy on the measurement uncertainty can be efficiently decreased by increasing the volume of the reservoir. The measurement uncertainty was estimated at 4.8％(k=2) after it was calibrated, and the calibrated high energy laser energy meter was compared with the other measurement systems, yielding a calibration coefficient of 1.006 and a standard deviation of 1.4% (k=2).