DEVELOPMENT OF A DOUBLE METAL, AC-COUPLED SILICON PAD DETECTOR

A large area radial silicon pad detector has been produced, tested, an d installed for the WA98 experiment at CERN. This paper describes the structure and the first test results of the silicon sensors used in th is detector. Double metal technology has been used to lead the signals from the inner pads to the edge of the sensitive region. The capacita nce for each pad has been measured and is shown to vary according to t he pad size. Signals from Sr-90 radiation have been analysed, and a si gnal-to-noise ratio of over 30 has been achieved. The RMS noise varies with the capacitance of each pad, and the variation agrees with the s pecification of the preamplifier. No evidence of cross talk due to the capacitance coupling between two metal layers has been observed.