User's guide for GRAAS version 3.0

GRAAS is a FORTRAN program written to run on the Control Data Corporation (CDC) 6600/CYBER 170 system at CRNL. It analyses gamma ray spectra individually producing printed, plotted, and/or tape output at the user's request. Peaks in a spectrum are recognized by examining the smoothed second derivative of the data. A Gaussian distribution on a straight line background is fitted to each peak which is determined to be statistically significant in order to determine its area. The corresponding energy of each peak may be found automatically from calibration spectra interspersed among the other spectra or from a separate input spectrum. GRAAS is usually run after the file maintenance program X2FM but an appendix explains how spectra from other sources may be processed