Radiation-hard Performance Research of Front-End Electronics for Fusion Diagnostic by Gamma Irradiation Experiment

In the environment of a fusion reactor, electronic systems are subjected to various influences including vibration, electromagnetic pulses, as well as irradiation from neutrons and gamma rays. Diagnostics systems on fusion reactors can accumulate radiation doses to a level where issues such as signal attenuation and system interruption can occur. Additionally, maintenance of electronic systems during fusion reactor experiments is often not feasible. Therefore, assessing the radiation tolerance of electronic systems used in fusion reactors is of paramount importance. To validate the radiation resistance of front -end electronics and cable in various diagnostic systems, a test circuit board was designed. This board integrates a variety of commonly used amplification chips and power supply chips to assess their performance in the environment of a fusion reactor. The experiment selected three different types of cables commonly used in fusion reactors for separate testing, to assess their parameter changes before and after irradiation experiments. Gamma Irradiation Experiments were conducted using a cobalt -60 (Co -60) radiation source at the Irradiation Center of Nanjing University of Aeronautics and Astronautics. The test circuit board was exposed to continuous gamma irradiation at two test points, with dose rates of 6 Gy/min and 1 Gy/min, respectively, for a total of 6.5 h, Data from the irradiation experiments were collected and analyzed. The results show that under continuous gamma irradiation, CJ7805 and AMS1117-5 chips stopped working at 586 Gy and 776 Gy, respectively. The output of the LT1175I5 chip dropped from -5 V to -1 V at 447 Gy. Apart from the radiation-resistant power supply chips, the output of other power supply chips slightly decreased. The signal reference of the charge amplifier dropped at 741 Gy but then slowly rose again, and the signal amplitude decreased at 900 Gy. The signal reference of the current amplification circuit remained unchanged, with a slight decrease in amplitude. The signal reference of the voltage amplifier exhibited jitter, with no change in amplitude. The experiment provides valuable data support for the radiation-resistant design of electronic systems in the environment of a nuclear fusion reactor.