Analysis of full charge reconstruction algorithms for X-ray pixelated detectors (original) (raw)
2011, 2011 IEEE Nuclear Science Symposium Conference Record
Existence of the natural diffusive spread of charge carriers on the course of their drift towards collecting electrodes in planar, segmented detectors results in a division of the original cloud of carriers between neighboring channels. This paper presents the analysis of algorithms, implementable with reasonable circuit resources, whose task is to prevent degradation of the detective quantum efficiency in highly granular, digital pixel detectors. The immediate motivation of the work is a photon science application requesting simultaneous timing spectroscopy and 2D position sensitivity. Leading edge discrimination, provided it can be freed from uncertainties associated with the charge sharing, is used for timing the events. Analyzed solutions can naturally be extended to the amplitude spectroscopy with pixel detectors. I. INTRODUCTION he goal of this work was to study charge reconstruction algorithms in pixel detectors with nominal pitch of 60 microns. The typical RMS spread of the photon charge has a Sigma of 10 microns[1]. The magnitude of the charge deposited is of the order of 2200 electrons (Monochromatic X-rays of 8keV in silicon, in our application x-ray photon correlation spectroscopy[2], produce 2200 electrons.), although the ability to detect smaller charges is generally desirable, and of course larger signals can occur. This charge is spread over up to four pixels, and charge reconstruction is in the summing nodes. The issue of charge sharing in pixilated photon detectors has been studied previously[3]. Several charge position reconstruction
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