Document 
Free access article
A&A 411, L141-L148 (2003)
DOI: 10.1051/0004-6361:20031367
Letter
ISGRI: The INTEGRAL Soft Gamma-Ray Imager
F. Lebrun1, J. P. Leray1, P. Lavocat1, J. Crétolle1, M. Arquès2, C. Blondel1, C. Bonnin1, A. Bouère1, C. Cara1, T. Chaleil3, F. Daly1, F. Desages4, H. Dzitko1, B. Horeau1, P. Laurent1, O. Limousin1, F. Mathy2, V. Mauguen1, F. Meignier1, F. Molinié3, E. Poindron1, M. Rouger4, A. Sauvageon1 and T. Tourrette11 CEA-Saclay, DSM/DAPNIA/Service d'Astrophysique, 91191 Gif-sur-Yvette Cedex, France,
2 CEA-Grenoble, LETI, 17 rue des Martyrs, Grenoble Cedex 9, France,
3 CEA-Saclay, DSM/DAPNIA/SIS, 91191 Gif-sur-Yvette Cedex, France,
4 CEA-Saclay, DSM/DAPNIA/SEDI, 91191 Gif-sur-Yvette Cedex, France
(Received 17 July 2003 / Accepted 4 September 2003)
Abstract
For the first time in the history of high energy
astronomy, a large CdTe gamma-ray camera is operating in space.
ISGRI is the low-energy camera of the IBIS telescope on board the
INTEGRAL satellite. This paper details its design and its
in-flight behavior and performances. Having a sensitive area of
2621 cm2 with a spatial resolution of 4.6 mm, a low threshold
around 12 keV and an energy resolution of ~8% at 60 keV,
ISGRI shows absolutely no signs of degradation after 9 months in
orbit. All aspects of its in-flight behavior and scientific
performance are fully nominal, and in particular the observed
background level confirms the expected sensitivity of 1 milliCrab
for a 10
6 s observation.
Key words: space telescope -- cadmium telluride detectors -- gamma-ray astronomy -- calibration -- INTEGRAL -- IBIS.
Offprint request: F. Lebrun, flebrun@cea.fr
© ESO 2003