Radiation effect on silicon transistors in mixed neutrons–gamma environment

• We measure the gain degradation after irradiation of BJT and JFET transistors.
• We model the reactor and transistors in order to calculate irradiation dose.
• The gain degradation was higher in BJT than in JFET.
• Neutrons and gamma dose contributions of reactor were 2% and 98%, respectively.
• The highest neutron contribution comes from the fast and resonance absorption neutrons.

The effects of gamma and neutron irradiations on two different types of transistors, Junction Field Effect Transistor (JFET) and Bipolar Junction Transistor (BJT), were investigated. Irradiation was performed using a Syrian research reactor (RR) (Miniature Neutron Source Reactor (MNSR)) and a gamma source (Co-60 cell). For RR irradiation, MCNP code was used to calculate the absorbed dose received by the transistors.The experimental results showed an overall decrease in the gain factors of the transistors after irradiation, and the JFETs were more resistant to the effects of radiation than BJTs. The effect of RR irradiation was also greater than that of gamma source for the same dose, which could be because neutrons could cause more damage than gamma irradiation.