An observed correlation between alpha-particle peak-fitting parameters

Using a silicon PIPS detector, a number of alpha-particle spectra were recorded from sources of different nuclide activities. These spectra were fitted using a ''Simplex'' computer programme. The fitting function contains a term which is the convolution of a truncated exponential with a Gaussian function. We have studied the variation of the value of the characteristic energy in the exponential with the value of the variance of the Gaussian. Both values are obtained from the best fits in the least-squares sense. After subtraction of baseline values, we find a significant correlation between the two parameters, which is attributed to the skewed distribution of the energy losses of the alpha-particles prior to detection. (author)