Radiation hardness characterisation of the monolithic amplifier system for the E831 microvertex detector

A new monolithic front-end system was purposely developed for the readout of the silicon microstrip vertex detector of the E831 fixed target experiment at Fermilab. The chip, fabricated in a JFET-CMOS-SIMOX technology, consists of 32 analog channels, performing signal preamplification and time-invariant shaping with 25 ns peaking time. The paper presents the results of the experimental characterisation of the radiation tolerance of the chip, which was irradiated with 60Co γ-rays up to a 400 krad integrated dose.