A study of low noise JFETs exposed to large doses of gamma-rays and neutrons

The monolithic process has proved able to retain the radiation hardness characteristics of discrete JFETs (junction field-effect transistors) up to 1 MGy (100 Mrad) of ⁶⁰Co γ rays. Neutron irradiation tests on discrete devices confirm that Si JFETs show very moderate damage up to 10¹³ Ncm^-2. In comparative tests Si JFET preamplifiers have been irradiated up to 600 kGy (60 Mrad) of γ rays and up to 4×10¹⁴ Ncm^-2. The preamplifiers were able to withstand the tests and have shown less radiation sensitivity than GaAs MESFET preamplifiers in the region of peaking times longer than ≈40 ns. The results are of interest in connection with the survival of front-end electronics for hadron collider experiments which may be subject to in excess of 30 Mrad of ionizing radiation and 10¹⁴ Ncm^-2 over a 10-year period