Development of a tritium accelerator mass spectrometer

An accelerator mass spectrometer (AMS) for direct atom counting of tritium has been developed using the Crocker Nuclear Laboratory´s (CNL) 76-in sector-focused cyclotron. Tritons were accelerated to 6.2 MeV and detected in a silicon Delta E-E charged-particle telescope. A detection efficiency of 2.4*10/sup -5/ was achieved with the smallest sample detected, which contained 2.6 mBq (70 fCi) of tritium at a T/H ratio of 3.7*10/sup -13/. Counting times were 3 to 6 min, with smaller samples requiring less time. This technique greatly reduces counting times and sample sizes from that required in existing beta -decay detection of ambient levels of tritium.<>