Characterization of M-π-n CdTe pixel detectors coupled to HEXITEC readout chip

Abstract

Segmentation of the anode-side of an M-π-n CdTe diode, where the pn-junction is diffused into the detector bulk, produces large improvements in the spatial and energy resolution of CdTe pixel detectors. It has been shown that this fabrication technique produces very high interpixel resistance and low leakage currents are obtained by physical isolation of the pixels of M-π-n CdTe detectors. In this paper the results from M-π-n CdTe detectors stud bonded to a spectroscopic readout ASIC are reported. The CdTe pixel detectors have 250 µm pitch and an area of 5 × 5 mm 2 with thicknesses of 1 and 2 mm. The polarization and energy resolution dependence of the M-π-n CdTe detectors as a function of detector thickness are discussed. KEYWORDS: Solid state detectors; X-ray detectors; Detector control systems (detector and experiment monitoring and slow-control systems, architecture, hardware, algorithms, databases); X-ray radiography and digital radiography (DR)

Characterization of Edgeless CdTe Detectors for use in Hard X-Ray Imaging Applications

“…The detector was fabricated by Acrorad Ltd and segmented by VTT Technical Research Centre of Finland using the diamond blade segmentation technique [8]- [10]. The anode was segmented into 20 20 pixels with a pitch of .…”

“…A voltage was applied to the detector using a bias refresh scheme to avoid the polarisation effect widely reported for Schottky CdTe detectors [10], [22]- [24]. A bias of was applied for 60 s followed by the application of 0 V for 1 s; this biasing scheme was found to keep the detector leakage, and count rate, stable over the course of the measurements for both detectors.…”

“…If tiled arrays are to provide efficient imaging, then the non-detecting area between detectors must be kept to a minimum and ideally be reduced to zero. One method of achieving this is the use of edgeless detectors which have no guard ring and where the active area extends right to the edge of the detector [8]- [10].…”

Materials identification using a small-scale pixellated x-ray diffraction system

“…simultaneous measurements over a range of scattering angles and X-ray energies [5,6]. PixD was developed with the use of the HEXITEC pixellated energy-resolving detector [7,8,9]. HEXITEC is made up of a 20 × 20 × 1 mm cadmium telluride (CdTe) crystal bump bonded to an application-specific integrated circuit (ASIC) to give an 80 × 80 pixel array with 250 ñm pitch.…”

Fluorescence lifetime imaging microscopy analysis of defects in multi-tube physical vapor transport grown Cd1−x Zn x Te

“…Spectroscopic detectors produced in Si do not have sufficient stopping power at these energies and Ge detectors require cryogenic cooling. Cadmium telluride (CdTe) and Cd‐rich ternary tellurides are better suited materials as they operate at room temperature and have excellent spectroscopic energy resolution of 0.8 keV measured at 60 keV . Despite this excellent performance, CdTe detectors are limited to 1 mm thickness due to large leakage currents at typical operating voltages >500 V. Cd 1− x Zn x Te (CZT) alloys with a Zn fraction of typically x ∼ 0.1 have a larger band gap and a higher resistivity than CdTe, which reduces leakage currents and permits thicker (>1 mm) detectors.…”