Performance of Convectron gauge operated by a power supply cable of 500 m long

A Pirani gauge is usually operated in an accelerator for monitoring the pressure in the beginning of the pump down process. In the high-intensity proton beam accelerator, the gauge controller/power supply, including some semiconductor electronic devices, is often failed due to high levels of radiation, when being installed near the accelerator. In order to install the power supply far out of the tunnel, performance of the Convectron gauge was examined by using longer cables than catalog-specified cable. The gauge was tested with cables of 3 to 500 m long. An inaccurate value in the pressure reading was indicated at the pressure above 1000 Pa, when the cable length was 200 m long, or more. The voltage offset generated by cable resistance exceeds an acceptable input range of the amplifier. Remodeling the controller, a long cable of 500 m long was able to be adopted. (author)