Adaptive digital filter for high-rate high-resolution gamma spectrometry

By automatically adapting the noise filtering time to individual pulse intervals, the preloaded digital filter (PLDF) combines low- to medium-rate resolutions comparable to those of high-quality Gaussian amplifiers with throughput rates of up to 100 kc/s and high-rate resolutions superior to those of state-of-the-art gated integrator systems. In contrast to commercially available digital filters, the PLDF in its new implementation performs pulse shortening as well as pole-zero cancellation in the analog domain. This not only results in a simpler digital core, but also, for the first time, makes possible the use of a low-cost analog-digital converter in a spectrometric application. Combined with real-time correction of counting losses according to the loss-free counting method, the PLDF is the core of a novel multichannel analyzer system for neutron activation analysis of short-lived isomeric transition.