Experimental results of the model coil for cooling design of a 1T cryocooler-cooled pulse coil for SMES

We have been developing high-Tc superconducting coil for SMES. Our primary goal is to make a HTS coil which is cooled to 40 K by a single-stage cryocooler and continuously operated at 1 Hz with a field amplitude of 1 T. The coil has heat drains of AIN plates to remove heat because of ac losses. We made a cooling model coil system to study the effective arrangement of the heat drains. The system consisted of a model coil using Cu conductors, current leads and a cryocooled system. The test coil was divided into three sections in different arrangement of heat drains. The model coil was daubed with the high thermal conductivity epoxy resin to improve thermal contact resistance between the conductors and AIN plates. We tested the coil by joule heating which was equal to ac losses. We measured the temperature distribution in the coil and the temperature difference between Cu conductors and AIN plates. The temperature difference was measured between 0.2 K and 0.7 K. The results will be applied to the 1 T HTS coil design.