CALISTE 64, an innovative CdTe hard X-Ray micro-camera

In the frame of the hard X-ray simbol-X observatory, a joint CNES-ASI space mission to be flown in 2013, a prototype of miniature camera equipped with 64 pixels has been designed. The device, called CALISTE 64, is a spectro- imager with high resolution event time-tagging capability. CALISTE 64 integrates a CdTe semiconductor detector with segmented electrode and its front-end electronics made of 64 independent analogue readout channels. This 10times10times18 mm
³
camera, able to detect photons in the range from 2 keV up to 250 keV, is an elementary detection unit juxtaposable on its four sides. Consequently, large detector array can be made assembling a mosaic of CALISTE 64 units. Electronics readout module is achieved by stacking four IDeF-X V1.1 ASICs in a 3D-module, perpendicular to the detection plane. We achieved good noise performances, with an equivalent noise charge better than 60 electrons rms in average. We choose CdTe detectors equipped with aluminum Schottky barrier contacts because of their very low dark current and excellent spectroscopic performances. The first integrated CALISTE 64 camera was realized and tested. The device operates properly and all the 64 pixels show good spectra. When the crystal is cooled down to -10degC and biased at -400 V, the resulting sum spectrum shows a spectral resolution of 697 eV FWHM at 13.9 keV and 808 eV FWHM at 59.54 keV. This paper presents the CALISTE 64 design and preliminary performance test results.