| 摘要 |
PURPOSE:To surely prevent an infrared detecting element in a cooling device from being damaged by serially connecting a superconductor with the element in the cooling device. CONSTITUTION:An electric current supplied from a power source terminal 8 through a constant-current circuit 6 is supplied to a superconductor line 21 from a seal terminal 22 and outputted to another seal terminal 23 through a semiconductor infrared detecting element 5. In a state where the element 5 is cooled with liquid nitrogen, the resistance value of the line 21 is zero and the electric current from the circuit 6 makes a bias current to flow to the element 5. When the liquid nitrogen evaporates from the container or filling up of the container with liquid nitrogen is forgotten, the line 21 shows a high resistance value. Therefore, the element 5 is surely protected and is not damaged, since the bias current from the circuit 6 is cut off. |
