Gamma-ray spectral analysis with the COSPAJ continuum fitting routine

We present a method to fit γ-ray full-energy peaks. Instead of performing a local fit to a limited number of channels around full-energy peaks simultaneously to the peak fit, it uses a spectral continuum fitting program, COSPAJ, to determine the peak base-line independently to the peak fitting. Full-energy peaks are described by the sum of two exponential distributions convoluted with a Gaussian. The method produces consistent results, accurate determinations of peak areas and it induces relative area uncertainties down to 0.02%.