Signal Processing for Semiconductor Detectors

Abstract

This is a tutorial paper designed to provide a ; balanced perspective on the processing of signals produced by semiconductor detectors. The general problems of pulse shaping to optimize resolution with constraints imposed by noise, counting rate and rise time fluctuations are discussed.'

Simultaneous ballistic deficit immunity and resilience to parallel noise sources: A new pulse shaping technique

“…In Fig. 1 we compare, on an arbitrary vertical scale, the CR-RC shaping network to other two shaping networks that are among the most commonly used in nuclear spectroscopy: the so-called sin 4 and sin 6 shaping networks. The amplitude of the responses to an ideal pulse (infinitesimal rise time) is normalized to 1 and the numbers in parenthesis show the time vs. amplitude value of the waveforms at the 1 This work was performed under the auspices of the Department of Energy under contract No.…”

“…This is especially bothersome at higher energies (above 100 keV) because of the longer interaction length of the more energetic photons [3]. When the detector material presents different mobility and trapping phenomena for electrons and holes, the resulting image charge induced on the collection electrode has a shape that depends on how far from such electrode the interaction took place [4]. Moreover, high energy photons also present Compton scattering phenomena that introduce complex structure in the image charge.…”

“…For example, often a practical solution for the mitigation of ballistic deficit is to simply choose a long(er) peaking time (where "long" is compared to the rise time at the output of the charge preamplifier and to its spread). It is also known that a long peaking time is usually associated with signals with an increased area and this implies degradation in electronic resolution due to low frequency noise contributions (both parallel and f 1 ) [4] and the consequential worsening of rate-handling capabilities of the pulse processing system. It is clear that in order to design a pulse shaping system immune to ballistic deficit one generally has to trade rate for resolution and tolerate the accentuation of low frequency noise terms [8].…”

Field Profile Tailoring in a-Si:H Radiation Detectors

“…7 ~ diode indicate that the main contribution to the measured noise in this bias range is due to delta noise [7] which is proportional to the diode capacitance.…”

Applications of a-Si:H radiation detectors

“…Since the a-Si:H layers in these devices are limited to a few 1. 1 m thickness and their electrodes are all parallel plates, the detector capacitance is fairly large and so is the noise component known as the delta noise in the standard nuclear electronics for single particle detection [ 4]. Therefore, it is difficult to operate these devices in pulse mode (counting individual panicles).…”