Low level gamma spectrometry by high speed digital sampling

Thermoluminescent dating usually involves estimation by dosimetry of environmental radiation. We use a NaI(Tl) crystal detection system in a massive Pb and Fe castle. Signal conditioning involves the usual preamplification, pulse shaping, discrimination and dedicated MCA. The successful use of a Phoswich detector (NaI(Tl) + CaF2(Eu)) for beta/gamma discrimination usually involved further stages of pulse processing and manipulation relying on the different pulse shape characteristics resulting from the different scintillator relaxation times (250 ns and 1000 ns respectively). The prospect of needing several NIM racks (Nuclear Instrument Modules) packed with various modules, all of which require tuning, has induced us to have another look at the overall problem of data collection and data analysis for low-level gamma counting, i.e. one event per second