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

The authors have been developing high-Tc superconducting coils for SMES applications. Their 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 AlN plates to remove heat because of AC losses. They 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 a high thermal conductivity epoxy resin to improve thermal contact resistance between the conductors and AlN plates. They tested the coil by Joule heating which was equal to AC losses. They measured the temperature distribution in the coil and the temperature difference between Cu conductors and AlN 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.