Silicon x-ray array detector on spectrum-x-gamma satellite
Abstract
The SPECTRUM-X-GAMMA mission objectives include broad- and narrow-band imaging spectroscopy from EUV to gamma rays. The major telescopes on board are two SODART x- ray telescopes with 8 m focal lengths. One of them includes the Finnish silicon x-ray array detector (SIXA) experiment as one of its focal plane instruments. SIXA's main task is to measure x-ray spectra with good resolution together with an imaging detector or polarimeter under the other parallel telescope. The original idea of fabricating 19 hexagonal measuring pixels on a single high resistivity silicon wafer has had to be rejected due to poor availability of material and project constraints. A nearly identical back-up detector is used instead. It consists of 19 discrete, circular, and closely packed Si(Li) detectors. The estimated resolution is 170 - 180 eV at 6 keV. A passive cooling system on the satellite provides 105 - 110 K operating temperature for the detector. The electronics system of the SIXA instrument has 19 parallel amplifier channels. Two parallel microprocessors are used to provide up to four simultaneous measurement modes for different scientific purposes. Memory is protected against single event upsets with hardware error detection and correction systems. Additional memory is provided by the use of two hard disks in hermetically sealed containers inside the instrument electronics box. This paper gives an updated description of the SIXA instrument concept. The results from preamplifier development tests are summarized and different detector concepts compared. Thermal questions connected with the detector unit and passive cooler design are discussed.
- Publication:
-
EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy II
- Pub Date:
- October 1991
- DOI:
- 10.1117/12.48342
- Bibcode:
- 1991SPIE.1549..246S
- Keywords:
-
- Imaging Spectrometers;
- Satellite-Borne Instruments;
- Silicon Radiation Detectors;
- Space Missions;
- X Ray Detectors;
- Extreme Ultraviolet Radiation;
- Gamma Ray Astronomy;
- X Ray Spectra;
- Spacecraft Instrumentation