Calorimetry by Boil-Off Measurement

Very low boil-off of cryogens is required for cryostats containing superconducting magnets used in various fields. It is important that the thermal insulating efficiency is improved. In order to accurately design the thermal insulating efficiency of components for cryostats, it is necessary to measure the emissivity of the thermal shielding plates and the average thermal conductivity of the multilayer insulation and supports. The boil-off calorimetry method has often been used for measurements of these low temperature heat transfer characteristics. In this review, applications of the boil-off calorimetry method and details of measurement are summarized.