Digital coincidence counting - initial results

Digital Coincidence Counting (DCC) is a new technique in radiation metrolog y, based on the older method of analogue coincidence counting. It has been developed by the Australian Nuclear Science and Technology Organisation (AN STO), in collaboration with the National Physical Laboratory (NPL) of the U nited Kingdom, as a faster more reliable means of determining the activity of ionising radiation samples. The technique employs a dual channel analogu e-to-digital converter acquisition system for collecting pulse information from a 4 pi beta detector and an NaI(TI) gamma detector. The digitised puls e information is stored on a high-speed hard disk and timing information fo r both channels is also stored. The data may subsequently be recalled and a nalysed using software-based algorithms. In this letter we describe some re cent results obtained with the new acquistion hardware being tested at ANST O. The system is fully operational and is now in routine use. Results for C o-60 and Na-22 radiation activity calibrations are presented. initial resul ts with Sm-153 are also briefly mentioned. (C) 2000 Elsevier Science B.V. A ll rights reserved.