Quantitative Thermal Desorption Spectrometry of Noble Gases in Solids

摘要

Quantitative thermal desorption spectrometry carried out with the doses below limits to avoid the creation of surface disorder, the interaction of gas atoms during the desorption cycle, the retrapping of helium during the desorption cycle, and the multiple occupation of traps by helium is described. These limits are quantified, and it is shown that in general small amounts of gas have to be detected. The accuracy with which the energy E and frequency factor nu can be extracted from a measured 1st order desorption peak is ultimately limited by shot noise in the mass spectrometer. This noise is quantified for both the static and dynamic modes of operation. Examples are given showing that accuracies of approximately 1% can be obtained for peaks with 100 million practicles for practically achievable values of L and S.