Dewar and biological magnetism measurement apparatus using the dewar

摘要

A DEWAR for SQUID is provided. In the DEWAR for SQUID, an amount of leak gas discharged from absorbent arranged in the upper portion higher than the liquid surface level of liquid helium is small even if the liquid surface level of the liquid helium is lowered. In order to attain the above object, a DEWAR in accordance with the present invention comprises an inner container for holding a SQUID magnetometer and a coolant, the inner container being made of a non-magnetic and electrically non-conductive material; an outer container for forming a thermal insulating space between the inner container and the outer container, the outer container being made of a non-magnetic and electrically non-conductive material; and a gas absorbing means provided inside the thermal insulating space, and the DEWAR further comprises a non-magnetic thermal conducting means in contact both with the gas absorbing means arranged at a level higher than a level of a holding position of the SQUID magnetometer and with a position of the inner container at a level lower than a level of the gas absorbing means.