CdTe sensor configurations for robot assisted photon counting gamma camera

Abstract

In this work, different Cadmium Telluride (CdTe) sensor configurations are assessed for the usage in a robot assisted portable gamma camera. In the first part, four CdTe sensors, with thickness of 0.45 mm, 1 mm, 2 mm and 3 mm and pixel sizes of 55 µm and 110 µm, are investigated regarding their spectroscopic performance. The photon counting detector Timepix1 is hereby used. The 3 mm CdTe sensor shows increase in count rate up to a factor of 1.25 compared to a 2 mm CdTe sensor, 1.84 compared to a 1 mm CdTe sensor and up to 2.71 compared to a 0.45 mm CdTe sensor in the case of 137 Cs. In the second part, the 3 mm CdTe sensor was implemented in a commercially available gamma camera, the iPIX. The system was integrated in the bomb disposal robot and tested in different scenarios. The integrated 3 mm CdTe detector measured 21.5 counts per second emitting from a 60 Co source with an activity of 2.8 ± 0.07 Gbq in 20 meters distance in an open environment. The acquisition time was 116 seconds. The angular resolution was sufficient for the user to localize the radioactive isotope inside the test structure.

Sub-pixel energy-weighting techniques for metallic contaminant highlighting in a pharmaceutical hard capsule using a Timepix3 CdZnTe hybrid pixel detector

“…In the past, this material has shown encouraging results in terms of performance [17,18] when combined with the Timepix ASIC [19,20]. Its photon absorption efficiency can be improved by increasing its thickness [21], which simultaneously increases charge-sharing [11,12]. For this study, a 2 mm thick CdZnTe sensor was bump-bonded to a Timepix3 ASIC.…”

Characterization of a 5 mm thick CZT-Timepix3 pixel detector for energy-dispersive γ-ray and particle tracking

“…is the decay constant with t 1/2 = 2.6029(8) yrs [25]. P emission denotes the probability of the γ-ray emission per decay: P emission,511 keV = 0.903 (9) and P emission, 1275 keV = 0.9994 (13) [25]. The numbers of detected i-line (511 or 1275 keV) photons N i were determined after spectrum decomposition by linearly extrapolating the 1275 keV line's Compton continuum towards lower energies and bin-wise count rate subtraction (see figure 14).…”

“…Thus, high-Z material has been evaluated for spectral x-ray imaging and spectral micro-CT [4]. With recent analysis methodology improvement towards a 3D reconstruction of particle interactions within the semiconductor sensors [5,6], enabled by the nanosecond-scale time resolution combined with a highly-segmented sensor, CdTe sensors were evaluated for use as single-layer Compton Cameras to search for locations of γ-radiation sources [7][8][9].…”