The digital ASIC for the Digital Front End Electronics of the SPI astrophysics gamma-ray experiment

The SPI spectrometer is one of the gamma-ray astronomy instruments that will be installed on the ESA INTEGRAL satellite intended to be launched in 2001 by the European Space Agency. The Digital Front-End Electronics sub-system (DFEE) is in charge of the real time data processing of the various measurements produced by the germanium (Ge) detectors and the Bismuth Germanate (BGO) anti-coincidence shield. The central processing unit of the DFEE is implemented in a digital ASIC circuit, which provides the real time association of the various time signals, acquires the associated energy measurements, and classifies the various types of physics events. The paper gives the system constraints of the DFEE, the architecture of the ASIC circuit, the technology requirements, and the strategy for test and integration. Emphasis is given to the high level language development and simulation, the automatic circuit synthesis approach, and the performance estimation.