Ultra-low-temperature device and method for refrigerating object to be refrigerated using the same

Abstract

Provided is an ultra-low-temperature device that enables the cold head of a refrigeration device to be coupled in a detachable manner so as to be capable of highly efficient heat transfer with respect to an object being cooled, while effectively suppressing the infiltration of heat into the object being cooled. This ultra-low-temperature device is equipped with: a cooled object container (); a cold head insertion unit () having a cylindrical part () and a base part (); a thermal coupling formation part () forming a thermal coupling part between the low-temperature end () of the cold head () and the base part (); and a heat switch () provided between the base part () and the cooled object (). The thermal coupling formation part () has refrigeration-device side recesses and protrusions () and insertion-unit-side recesses and protrusions (), with the thermal coupling part being formed by the freezing of a gaseous heat transfer medium in the gaps () between these recesses and protrusions. The heat switch () has an insertion-unit-side heat switch element provided on the base part (), and a cooled-body-side switch element, and the transfer of heat is enabled or prevented on the basis of whether the switch elements are in contact or are separated from each other.