Digital beta counting and pulse-shape analysis for high-precision nuclear beta decay half-life measurements: Tested on Alm26

A digital β-counting method has been developed for high-precision nuclear β-decay half-life experiments that use a gas proportional counter. An 8-bit, 1-GS/s sampling-rate digitizer was used to record the waveforms from the detector and a software filter was designed, tested and applied successfully to discriminate genuine β-decay events from spurious signals by pulse-shape analysis. The method of using a high-speed digitizer for precision β counting is described in detail. We have extensively tested the digitizer and the off-line filter by analyzing saved waveforms from the decay of Alm26 acquired at rates up to 10,000 per second. The half-life we obtain for Alm26 is 6345.30±0.90 ms, which agrees well with previous published measurements and is as precise as the best of them. This work demonstrates the feasibility of applying a high-speed digitizer and off-line digital signal processing techniques for high-precision nuclear β-decay half-life measurements.