A Si/CdTe Compton Camera for gamma-ray lens experiment

Abstract

Cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) have been regarded as promising semiconductor materials for hard X-ray and γ -ray detection. However, a considerable amount of charge loss in these detectors results in a reduced energy resolution. We have achieved a significant improvement in the spectral properties by forming the Schottky junction on the Te side of the CdTe wafer. With the further reduction of leakage current by an adoption of guard ring structure, we have demonstrated a CdTe pixel detector with high energy resolution and full charge collection capabilty. The detector has a pixel size of a few mm and a thickness of 0.5 − 1 mm. We apply this high resolution detector to a new silicon and CdTe Compton Camera which features high angular resolution. We also describe a concept of the stack detector which consists of many thin CdTe layers and provides sufficient efficiency for hard X-rays and gamma-rays up to several hundred keV maintaining good energy resolution. A narrow-FOV Compton telescope can be realized by installing a Si/CdTe Compton Camera inside the deep well of an active shield. This configuration is very suitable as focal plane detector for future focusing gamma-ray missions.

Prospects and requirements for measurements of extragalactic γ-ray lines

“…2 Suzaku HXD sensitivity [13]. For an updated version, see [22] -this volume Fig. 3 Spectral energy distribution from a cluster following positron injection by an AGN at various times.…”

Observation of Diffuse Cosmic and Atmospheric Gamma Rays at Balloon Altitudes With an Electron-Tracking Compton Camera

“…Recently, in addition to an ETCC, balloon experiments with new detection methods have been performed to achieve higher sensitivity in the sub-MeV/MeV band. For example, a double-Compton camera using a liquid Xe detector: the LXeGRIT (Aprile et al 2008); multiple Compton cameras (Kamae et al 1987) by using semiconductors: the nuclear Compton telescope (NCT; Boggs et al 2007), a Si/CdTe Compton telescope (Takahashi 2005), and the Tracking and Imaging Gamma Ray Experiment (TIGRE; Zych et al 2008); an electrontracking Compton camera using an electron tracker made of a semiconductor: the Medium Energy Gamma-ray Astronomy (MEGA) telescope (Bloser et al 2006); and a gamma-ray lens: CLAIRE (von Ballmoos et al 2005). Also, such experiments have renewed the attention given to observations of diffuse cosmic gamma rays, atmospheric gamma rays, and the background formed by cosmic rays at balloon altitudes.…”

Estimation of energy range measurements with newly developed Si/CdTe Compton camera for nuclear medicine imaging

“…The upper layer of the detectors, called the "scatterer detector," is made of Si and the Compton scattering of incident gamma rays occurs here. The lower layer, called the "absorber detector," is made of CdTe, and scattered gamma rays are absorbed here [2][3][4][5][6][7][8][9][10][11][12][13].…”