Three-dimensional position sensitivity in two-dimensionally segmented HP-Ge detectors

GRETA — Gamma Ray Energy Tracking Array

“…It gives an excellent energy resolution for all the segments; about 1.9 keV for 1.33 MeV gamma rays and 1.2 keV for 60 keV gamma rays [5]. Extensive position sensitivity measurements have been carried out on this prototype and they demonstrated that the position of a single interaction within a segment could be determined with an accuracy of about 1 mm in all three dimensions [6]. In these measurements, to ensure a single interaction at a well-defined position, we used a collimated 137 Cs source and collimated NaI detectors to detect the Compton scattered gamma ray at 90 degrees in coincidence with the signal in the Ge detector.…”

Position resolution studies with MSU 32-fold segmented HPGe detector

“…The segmentation scheme allows for a position-dependent Doppler correction to be applied, yielding better energy resolution and improved spectrum quality. As we have shown in our previous work, position resolution can be much smaller than segment size if digital pulse shape analysis is used [1]. We discuss here the best 3-D position resolution achievable in the MSU detector and how that resolution varies with location in the crystal.…”

“…4. We calculated expected signals from the electric field and weighting potentials as in [1]. Further, these signals were convolved with the measured preamplifier responses.…”

“…Position sensitivity was calculated as in [1]. The noise level was measured to be about 6 keV for all segments, and this constant value was used in the calculations.…”

“…F OR the last several years, we have been studying position resolution in segmented high-purity germanium (HPGe) detectors [1], [2]. A three-dimensional position resolution is a prerequisite for the concept of gamma-ray tracking based on the Compton process, which allows imaging of gamma-ray source locations.…”