The space-borne INTEGRAL-SPI gamma ray telescope: test and calibration campaigns

The SPI, Spectrometer aboard the ESA INTEGRAL satellite, to be launched in 2002, will study the gamma ray sky in the 20 keV to 8 MeV energy band with a spectral resolution of 2 keV for photons of 1 MeV thanks to its 19 germanium detectors. A coded mask imaging technique provides a 2/spl deg/ angular resolution. An active BGO veto shield is used for background rejection. After the integration and test campaigns at CNES in Toulouse, the flight model of SPI has undergone a one month pre-launch calibration campaign at the CEA center of Bruye/spl grave/res le Cha/spl circ/tel, using an accelerator for homogeneity measurements and high activity radioactive sources for imaging performance measurements. After presentation of the scientific goals and the different detector components, we report on the SPI measurement campaigns. We emphasize the methods used to achieve a good timing alignment using the digital front end electronics and present first detector performance and imaging capabilities.