PURPOSE: To back up the increase of a power current generated as the radioactive ray dose rate is temporarily increased by providing a main power source, a backup power source and a discharge circuit discharging the power of the backup power source, and receiving the feed of the power from the main power source and the discharge circuit to operate electronic circuits.
CONSTITUTION: Electronic circuits 22, 24 are constituted of CMOS IC with semiconductor elements such as MOSFET, and the power from the main power source 10 is fed to the electronic circuits 22, 24 via a power line 30 and switches 26, 28. The power of the main power source 10 is fed to a backup power source 12 via a power line 32, a charge circuit 14 and a power line 34, and the backup power source 12 is charged by the power from the main power source 10. The output side of the backup power source 12 is connected to the power line 30 via a power line 36, a discharge circuit 20 and a power circuit 38, and the power of the backup power source 12 is fed to the electronic circuits 22, 24 when a discharge command is outputted to the discharge circuit 20 from a control device 16. Signals from a radioactive ray sensor 18 are inputted to the control device 16, and a discharge command is outputted to the discharge circuit 20 from the control device 16 when the radioactive ray dose rate exceeds a preset value.
SHIGENAKA NAOTO
FUSE MOTOMASA
