Induction cores, used to accelerate the heavy ion beams in inertial fusion, are built around the outer diameter of the cryostat that houses the superconducting quadrupole array. A compact cryostat would be highly desirable for reducing the cost of the induction cores. Recent experience with the fabrication of a cryostat for single beam transport revealed that the spacing in the cryostat vacuum jacket could be reduced by using low-emissivity thermal insulation material instead of conventional MLI. However, compared with MLI, the installation of the new type of insulation is labor-intensive. To address this problem, this project will investigate the possibility of combining the low-emissivity material with conventional MLI as the cryostat insulation material. Phase I will design and fabricate two small cryostats. In each, a specific kind of low-emissivity insulation material will be combined with the MLI, and the vacuum jacket spacing will be built as compact as practical. The cryostats will be filled with liquid helium and the heat leak rate will be evaluated by monitoring the change in helium level. The test results will be used to select an optimal combination of the insulations. The selected mixed insulation will be used to build prototype compact cryostats in the Phase II.
Commercial Applications and Other Benefits as described by the awardee: The compact cryostat with the combined insulation should find use in superconducting magnets for a wide range of applications including particle accelerators, fusion energy research, NMR, NMI, laboratory high field experiments, and industrial magnets
