Two important problems are discussed: equations and data used for quantitation on one hand, diffusion under irradiation on another hand. It is suggested that recent semiempirical stopping power data for hydrogen and helium are sufficiently accurate to be used in any good calibration method, while for heavier ions it is preferable to use the "double reaction method", which avoids the use of stopping power data. The problem of the additivity of the stopping powers in the case of compounds is also discussed and it is shown in a specific case that BRAGG-KLEEMAN's rule is valid. Deep diffusion under irradiation has sometimes been mentioned (e.g. F in Ge, Cu in Si): it can be an important source of errors in trace analysis. The possible deep diffusion of F in Ge has been studied: it is shown that such a diffusion does not occur, while surface contamination problems can lead to erroneous observations.
ASJC Scopus subject areas
- Molecular Medicine
- Radiology Nuclear Medicine and imaging