CHOOSING FITTING FUNCTIONS TO DESCRIBE PEAK TAILS IN ALPHA-PARTICLE SPECTROMETRY

We seek to identify the major differences between two types of peak-fi tting programs for alpha-particle spectrometry. One function is the we ll-known convolution of a Gaussian function with two (usually) left-ha nded exponential functions. The other function is contained in an anal ysis program described by Koskelo et al. (Koskelo, M. J., Burnett, W. C, and Cable, P. H. (1996) An advanced analysis program for alpha-part icle spectrometry. Radioactivity Radiochem. 7(1), 18) and has one tail ing parameter which can be adjusted to generate a modified Gaussian wh ich is skewed towards lower energies. Recently an inter-laboratory exe rcise (Euromet 325) has provided some data which can be used to compar e the two fitting functions. We present some results using the SRIM pr ogram (Ziegler, J. F., Monte-Carlo Program TRIM contained in Program s uite SRIM version 96.xxx, 1996) and discuss what might be the underlyi ng physical phenomena described by the fitting functions. (C) 1998 Els evier Science Ltd. All rights reserved.