高分辨率谱仪的最小噪声共享基线恢复.pdf

Nuclear Instruments and Methods in Physics Research A 482 (2002) 441–448 Shared baseline restoration at minimum noise for high resolution spectroscopy A. Geraci, I. Rech, E. Gatti*, G. Ripamonti Politecnico di Milano, Dipartimento di Elettronica e Informazione, Piazza Leonardo da Vinci 32, Milano 20133, Italy Received 1 July 2000; accepted 12 July 2001 Abstract Optimum filter theory in Nuclear Spectroscopy is revisited, taking into account the noise contribution o fthe baseline estimator (baseline restorer or other suitable filter). An overall optimization o fthe signal-to-noise ratio is performed, and new filters are obtained. They include as particular cases the cusp filter and the Deighton filter. The theory is carried out by considering only series voltage noise, but it can easily be expanded to include parallel current noise. r 2002 Elsevier Science B.V. All rights reserved. Keywords: Baseline restoration; High resolution spectroscopy 1. Introduction immune to baseline level shifts [3]. The second consists in using temporally distinct filters: one for In any spectroscopy system, signals at the output measuring at best the pulse amplitude, the other(s) o fthe shaper amplifier are always overlapped to a for measuring at best the baseline level in time voltage baseline level. This level is not stable and interval(s) where no pulse are present. Then the needs to be estimated and subtracted from the filter outputs are weighed and summed up so that signal, in order not to reduce accuracy o fthe the resulting overall filter b