飞行时间质谱计测量结果的修正  

CORRECTIONS OF TOF MASS SPECTROMETER MEASUREMENTRESULTS

作　　者：李宁[1] 金奇计[1] 

机构地区：[1]清华大学电子工程系,北京100084

出　　处：《真空与低温》1999年第4期233-237,共5页Vacuum and Cryogenics

摘　　要：清华大学研制的小型飞行时间质谱计（ＴＯＦＭＳ） 体积小，且具有质量范围宽，全谱分析快等优点，分辨率亦满足要求。检测系统对ＴＯＦＭＳ的性能有很大影响。目前采用的时间－ 数字转换器（ＴＤＣ） 检测系统中存在“多个离子同时到达”和“死时间”效应，它们使ＴＯＦＭＳ在大计数率下产生严重的数据丢失、谱图变形，给成分分析带来很大不便，还大大降低了系统的线性范围。讨论了多个离子同时到达和死时间效应的起因和危害，并提出了有效的修正方法。通过修正，在一定范围内消除了上述两种效应给ＴＯＦＭＳ带来的负面影响。它不仅使测量的准确度大大提高， 还有效地扩大了线性范围，结果令人满意。The novel Mini-TOFMS developed in Tsinghua university not only has a large mass range and a high analysis speed,but also realized good resolution in a small volume.A detection system plays an important role in the performance of TOFMS.There exist simultaneous ion arrival and dead time effects in the time-to-digital converter,which is used in the detection system.These effects cause data loss and spectrum distortion at high detection rate and greatly limit the linear range of the spectrometer.This paper discusses simultaneous ion arrival and dead time effects in detail,and gives an effective correction method to eliminate the bad influence caused by the two effects.After the correction,both the precision and the linear range of the sprectrometer were largely improved.The result is satisfactory.

关 键 词：飞行时间质谱计 死时间效应 线性范围 修正 

分 类 号：TL817.8[核科学技术—核技术及应用]