| 摘要 |
PROBLEM TO BE SOLVED: To sufficiently cool a heat shield body to a low temperature, reduce the amount of heat intrusion due to radiation heat, and reduce the amount of evaporation of liquid helium. SOLUTION: As a heat transfer medium means of a heat shield body 1, for example, a nonmagnetic helium gas with a large heat conduction rate is airtightly sealed into each channel 5 that is constituted by laminating an edge part 3 and a separation part 4 of a film 2 such as two lamination films made of a nonmagnetic material and a polyester film with a nonmagnetic adhesive or by welding materials. Regarding the outer surface part of the film 2, an aluminum film with a film thickness of several μm is formed by vapor deposition to prevent the helium gas of the sealed heat transfer medium from leaking through a sheet. Although aluminum has improved electrical conductivity, the film thickness is less than 0.1 mm, so that an induction current is small and a magnetic noise is fully small. |
