Experimental heat leak measurements on the APT 210 KW CW RF power coupler

摘要

A cryogenic test rig was designed and fabricated to measure the heat leak from room temperature to 2 K for the Accelerator production of Tritium (APT) 700 MHz, 210 kW continuous wave (CW) co-axial power coupler (PC). The outer conductor of the PC is stainless steel with 15 μm copper film on the inside. The copper inner conductor operates at room temperature and contributes considerable infra-red radiation heat load to 2 K. Two thermal intercept heat exchangers cooled by supercritical helium are incorporated into the outer conductor to reduce the heat conducted to the lowest temperatures. A brief description of the experimental apparatus is presented. A comparison of the experimental measurements and the predictions of a detailed thermal model is given. There is also a discussion of anomalous behavior observed in the thermal intercepts, and fluctuations in the helium coolant properties.