Astrophysics, abstract
astro-ph/0604365

From: Hiroyasu Tajima [view email]

Date: Mon, 17 Apr 2006 22:53:37 GMT (405kb)

Design and Performance of the Soft Gamma-ray Detector for the NeXT mission

Authors: H. Tajima (1), T. Kamae (1), G. Madejski (1), T. Mitani (2 and 3), K. Nakazawa (2), T. Tanaka (2 and 3), T. Takahashi (2 and 3), S. Watanabe (2), Y. Fukazawa (4), T. Ikagawa (5), J. Kataoka (5), M. Kokubun (3), K. Makishima (3), Y. Terada (6), M. Nomachi (7), M. Tashiro (8) ((1) Stanford Linear Accelerator Center, (2) Institute of Space and Astronautical Science, (3) University of Tokyo. (4) Hiroshima University, (5) Tokyo Institute of Technology, (6) RIKEN, (7) Osaka University, (8) Saitama University)

Comments: 9 pages, 17 figures, Contributed to IEEE Nuclear Science Symposium, Roma, Italia, October 16-October 22, 2004

Report-no: SLAC-PUB-11828

Journal-ref: IEEE Transactions on Nuclear Science, 52, 2749-2757 (2005)

The Soft Gamma-ray Detector (SGD) on board the NeXT (Japanese future high energy astrophysics mission) is a Compton telescope with narrow field of view (FOV), which utilizes Compton kinematics to enhance its background rejection capabilities. It is realized as a hybrid semiconductor gamma-ray detector which consists of silicon and CdTe (cadmium telluride) detectors. It can detect photons in a wide energy band (0.05-1 MeV) at a background level of 5 x 10^-7 counts/cm^2/s; the silicon layers are required to improve the performance at a lower energy band (<0.3 MeV). Excellent energy resolution is the key feature of the SGD, allowing it to achieve both high angular resolution and good background rejection capability. An additional capability of the SGD, its ability to measure gamma-ray polarization, opens up a new window to study properties of astronomical objects. We will present the development of key technologies to realize the SGD: high quality CdTe, low noise front-end ASIC and bump bonding technology. Energy resolutions of 1.7 keV (FWHM) for CdTe pixel detectors and 1.1 keV for Si strip detectors have been measured. We also present the validation of Monte Carlo simulation used to evaluate the performance of the SGD.

http://arxiv.org/abs/astro-ph/0604365