Radiation damage tests of GaAs HV switches for MSGCs bias control

GaAs optoelectronic switches as local control of the HV MSGCs strips are being developed for the CMS experiment. The radiation environment inside the CMS tracker will be very high. Typical hadron fluence will be up to approximate to 10(14) cm(-2) and ionising doses as large as 100 kGy during the experiment lifetime. The aim of this work is to test the performance of some GaAs devices in terms of radiation hardness up to the levels of hadron fluence and ionising doses expected inside the CMS tracker.