Loss-free counting with a digital spectrometer and a software program

The computer program LFREE was written to do loss-free counting with a digi tal spectrometer. It runs in parallel with the normal data acquisition soft ware and corrects the counting losses once per second without interrupting data acquisition. The spectrometer's live time clock is used to measure the live time fraction. Tests showed that losses are accurately corrected at v ariable count rates which cause dead times as high as 80%. For half-lives o f the order of 10 seconds, the accuracy is limited by the response of the l ive time clock to very rapidly changing count rates.