Letter to the Editor

IBIS: The Imager on-board INTEGRAL

¹ Istituto di Astrofisica Spaziale e Fisica Cosmica, CNR, via del Fosso del Cavaliere 100, 00133 Roma, Italy
² CEN, Saclay, 91191 Gif-sur-Yvette Cedex, France
³ IASF-Bologna, via P. Gobetti 101, 40129 Bologna, Italy
⁴ School of Physics and Astronomy, University of Southampton, Highfield, Southampton, S017 1BJ, UK
⁵ University of Bergen, Allegaten 55, 5007 Bergen, Norway
⁶ IASF-Palermo, via U. La Malfa 153, 90146, Palermo, Italy
⁷ IASF-Milano, via Bassini 15, 21033, Milano, Italy
⁸ Marshall Space Flight Center, NASA, Ec 43, 35812 Huntsville, Alabama, USA
⁹ University of Valencia, Dr. Moliner 50, 46100 Burjasot, Spain
¹⁰ INTA, Carretera de Ajalvir km. 4 Torrejon 28691, Torrejon de Arzon (Madrid), Spain
¹¹ Univ. of Tübingen, Inst. for Astronomy and Astrophysics (IAAT), Sand 1, 72076 Tübingen, Germany
¹² Copernicus Astronomical Centre Bartycka 18 00716 Warsaw, Poland

Corresponding author: P. Ubertini, ubertini@rm.iasf.cnr.it

Received: 9 July 2003
Accepted: 8 August 2003

Abstract

The IBIS telescope is the high angular resolution gamma-ray imager on-board the INTEGRAL Observatory, successfully launched from Baikonur (Kazakhstan) the 17th of October 2002. This medium size ESA project, planned for a 2 year mission with possible extension to 5, is devoted to the observation of the gamma-ray sky in the energy range from 3 keV to 10 MeV (Winkler [CITE]). The IBIS imaging system is based on two independent solid state detector arrays optimised for low ( keV) and high ( MeV) energies surrounded by an active VETO System. This high efficiency shield is essential to minimise the background induced by high energy particles in the highly excentric out of van Allen belt orbit. A Tungsten Coded Aperture Mask, 16 mm thick and ~1 squared meter in dimension is the imaging device. The IBIS telescope will serve the scientific community at large providing a unique combination of unprecedented high energy wide field imaging capability coupled with broad band spectroscopy and high resolution timing over the energy range from X to gamma rays. To date the IBIS telescope is working nominally in orbit since more than 9 month.