Depth of interaction and bias voltage depenence of the spectral response in a pixellated CdTe detector operating in time-over-threshold mode subjected to monochromatic X-rays

Abstract

Fröjdh, E. et al. (2012) Depth of interaction and bias voltage depenence of the spectral response in a pixellated CdTe detector operating in time-over-threshold mode subjected to monochromatic X-rays. Journal of Instrumentation, 7 (3).

HEXITEC: A High-Energy X-ray Spectroscopic Imaging Detector for Synchrotron Applications

“…At 60 keV the mean free path of a -ray is 0.26 mm while at 122 keV it is 1.70 mm, as the sensor is only 1 mm thick, this means that the higher energy -rays are capable of depositing energy at any depth in the sensor. Those events that occur close to the pixelated anode will suffer from a larger contribution from the hole charge carrier leading to greater low-energy tailing and a reduction in spectroscopic performance [17]. The CSD spectrum recorded by each of the 6,400 channels of the detector can be summed together to produce a single global spectrum which also demonstrates the excellent uniformity of the sensors.…”

Energy calibration of a CdTe X-ray pixel sensor hybridized to a Timepix chip

“…This prevents an efficient reconstruction of incident X-ray spectrum and can therefore limit the applications of fine pitch CdTe sensors for energy-resolved X-ray imaging at high energy. To be noted, results obtained in [5,6] suggest that this effect is reduced with a pixel size of 110 µm instead of 55 µm.…”

“…Acquisitions in cluster-processed TOT mode are performed at different energies: monochromatic synchrotron beam at SOLEIL (6,10,15,20, and 25 keV), irradiation with 55 Fe (5.9 keV), 109 Cd (22-25 keV), 241 Am (59.5 keV) and 57 Co (122 keV) gamma ray sources at ESRF and CEA-LETI. Photopeaks in the image histograms are identified and fitted with Gaussians, and the TOT values corresponding to the peaks center positions are extracted as a function of the incident photon energy (figure 4).…”

A GEANT4 based simulation for pixelated X-ray hybrid detectors

“…Similar procedures can be employed to study defects on high-Z sensor materials [10,11] and also to monitor the detector characteristics as it is irradiated along time and its material properties can change according to a possible non-homogeneous radiation dose accumulated at different regions of the detector geometry [12]. However, there are not such measurements for thin silicon pixel hybrids available for comparison in the literature yet.…”