IBIS Home Page at the IAAT

Welcome to the INTEGRAL IBIS home page at IAAT. It is located at the section Astronomy of the Institute for Astronomy and Astrophysics of the University of Tübingen (IAAT).

Overview

IBIS is an instrument for detailed gamma ray imaging on board of the INTEGRAL satellite, the International Gamma-Ray Astrophysics Laboratory. This satellite is dedicated to observe with high spectroscopic and angular resolution celestial gamma ray sources. It will be launched in April 2002. Two main instruments (Spectrometer SPI and Imager IBIS) and two monitors (optical OMC and X-Ray) will observe in parallel celestial objects of all classes.

The Imager IBIS

IBIS is designed to provide images in the energy range from 15 keV and 10 MeV. The angular resolution is about 12 arcmin, but the source location accuracy is about 1 arcmin. This will be achieved by an coded mask imaging system and a detector array.

The detector consists of two layers:

a front layer of 128 x 128 Cadmium - Telluride semiconductor detectors (ISGRI) with an energy range from 15 keV to about 500 keV.
a succeeding layer of 64 x 64 Caesium - Iodide - scintillation--pixels (PICsIT) with an energy range from 15 keV to 10 MeV.

Lateral radiation is shielded by an active BGO-detector veto system and a passive W-Pb foil. This arrangement provides a wide spectral range with good spectral resolution (>10%) and a high continuum sensivity.

Data Handling System (DHS)

IBIS has to cope with very high data rates (> 15.000 events/sec) from two detector layers (ISGRI and PICsIT). Because the available telemetry rate is only about 1/30 of the expected maximum data rate an on-board data reduction and pre-processing is neccessary. This task is performed by a tailored fast Hardware Event Preprocessor (HEPI) and a slow programmable Data Processing Electronics (DPE). Several processing modes can be combined to adapt the instrument IBIS to the aims of the observers.

The HEPI electronics (board and FPGA/ASIC) is completly developed at IAAT. Also the data processing part of the DPE software is written here. A lot of people of the institute and external manufactors are involved in this work.