超灵敏度检漏仪校准技术进展

The Development of Calibration of Ultrasensitive Leak Detection

本文综述了国际上超灵敏度检漏仪的校准技术进展。超灵敏度检漏仪是高可靠长寿命真空器件封装的重要检漏工具,当前报道的检漏下限可达10−16 Pa·m^(3)/s,但检漏结果的正确性是器件可靠性的关键因素。超灵敏度检漏结果正确性主要取决于检漏仪的自身性能和计量校准,对于后者,国际上先后采用标准漏孔、可变漏率的白金丝漏孔及标准气体流量计作为参考标准来提高检漏结果的正确性。采用标准漏孔的方法是使用当前下限仅为10−11 Pa·m^(3)/s的漏孔作为参考标准,由于漏孔自身的偏差及检漏采用质谱计跨越几个数量级的线性递推方法,在小于10−14 Pa·m^(3)/s范围的检漏结果偏差可达一个数量级;采用可变漏率的白金丝漏孔作为参考标准,可提供(10−10~10−12)Pa·m^(3)/s范围内漏率,与标准漏孔相比对检漏结果的正确性有一定提升;采用近期新研制的宽量程标准气体流量计作为参考标准,可提供下限为10−16 Pa·m3/s范围内漏率,解决了目前超灵敏度检漏仪全量程的校准难题,将检漏结果的合成标准不确定度减小到15%以内,提升了长寿命真空器件的可靠性。

In this paper,the development of calibration of ultrasensitive leak detection in the world is reviewed.The ultrasensitive leak detector is a significant tool for packaging high reliability and long-life vacuum devices,at present,the reported lower limit of that can reach 10−16 Pa·m3/s.However,the correctness of leak detection results is the key factor for device reliability,which mainly depends on the performance and calibration of the leak detector.The standard leak,the platinum wire leak with variable leak rates and the standard gas flowmeter have been used as reference standards to improve the correctness of leak detection results for long years all over the world.The method of the standard leak is to use the leak with the current lower limit of only 10−11 Pa·m^(3)/s as the reference standard.Due to the deviation of the leak itself and the linear recurrence method of mass spectrometer spanning several orders of magnitude,the deviation of the leak detection results in the range of less than 10−14 Pa·m^(3)/s can reach one order of magnitude.Using the platinum wire leak as the reference standard can provide variable leak rates in the range of(10−10~10−12)Pa·m^(3)3/s,and the leak detection results will be more accurate compared with the standard leak method.In recent years,the newly developed standard gas flowmeter with a lower limit of 10−16 Pa·m^(3)/s solves the calibration problem of the ultrasensitive leak detector in the whole measurement range,reducing the combined standard uncertainty of the leak detection results to less than 15%,and improving the reliability of long-life vacuum devices.