Radiation effects at cryogenic temperatures in Si-JFET, GaAs MESFET, and MOSFET devices

Front-end electronics for liquid ionization chamber calorimetry at hadron collider experiments may be exposed to substantial levels of ionizing radiation and neutron fluences in a cryogenic environment. Measurements of devices built with rad-hard technologies have shown that devices able to operate in these conditions exist. Several families of devices (Si-JFETs, rad-hard MOSFETs, and GaAs MESFETs) have been irradiated and tested at a stable cryogenic temperature up to doses of 55 Mrad of ionizing radiation and up to neutron fluences of 4/spl times/10/sup 14/ n/cm/sup 2/. Radiation effects on DC characteristics and on noise will be presented.