极小气体流量测量技术研究  

Measurement of Extremely Low Gas Flow

作　　者：李得天 冯焱 成永军 张涤新 郭美如 

机构地区：[1]兰州物理研究所真空低温技术与物理重点实验室,兰州730000

出　　处：《真空科学与技术学报》2011年第4期435-439,共5页Chinese Journal of Vacuum Science and Technology

摘　　要：介绍了固定流导法极小气体流量测量技术,利用流导值为10-9m3/s量级的精密小孔,通过在10-110 Pa范围内调节进气压力,实现了10-810-10Pa·m3/s的流量测量,合成标准不确定度为0.94%。利用流导比值为187.9的两个激光小孔,将固定流导法产生了流量分流为总流量的0.53%,实现了10-1010-12Pa·m3/s范围内流量的测量,合成标准不确定度为1.2%。利用极小气体流量测量技术校准了小于10-8Pa·m3/s量级的真空漏孔,而且避免了四极质谱计的非线性引入的测量不确定度。与现有气体流量测量技术相比,提出的极小气体流量测量技术将测量下限延伸了4个数量级。A novel technique was developed to measure an extremely low gas flow rate,based on constant conductance method.In the technique,the pressure of the inlet gas was adjusted in a range between 10-1 Pa to 10 Pa so that the gas passes the orifice at a conductance of 10-9 m3/s.As a result,the measurement of the extremely low gas-flow rate ranges from 10-10 Pa·m3/s to 10-8 Pa·m3/s with a combined standard uncertainty of 0.94%.The gas flow,generated by a dedicated gas flow meter designed in constant conductance method,is then injected into a separate flow chamber with orifices.Since the conductance ratio of the two orifices was designed to be 187.9,only 0.53% of the gas flow enters the calibration chamber.The newly-developed technique makes it feasible to measure the extremely gas flow rate ranging from 10-12 Pa·m3/s to 10-10 Pa·m3/s,with a combined standard uncertainly of 1.2%.Moreover,when it comes to the calibration of a leak rate lower than 10-8 Pa·m3/s,the new technique outperforms the method based on quadrupole mass spectroscopy.Moreover,the technique has reduced the lower limit of gas flow rate of the conventional methods by a factor of 104.

关 键 词：极小气体流量 固定流导法 分流法 漏率校准 

分 类 号：TB77[一般工业技术—真空技术]