| 摘要 |
PURPOSE:To improve the reflectance of a radiation shield and improve thermal insulating characteristics with a simple structure by a method wherein a surface of the radiation shield opposing to a low temperature side of a vacuum thermal insulation tank is made of a super-conductive material kept at its super-conductive condition and a surface of the radiation shield opposing to a hot temperature surface side is made of material having a high rate of reflection such as silver or aluminum and the like. CONSTITUTION:A super-conductive radiation shield 1 is composed of a thin film 5 of material having a high reflectance such as silver or aluminum and the like and of a super-conductive material 1a. The thin film side is faced to a hot temperature side and the superconductive material 1a. is faced to a low temperature side. Radiation heat radiated from a vacuum thermal insulation tank wall 2a is reflected, for its light having a wavelength shorter than that of a visible light, with a material 5 having a high reflectance. its light having a wave length longer than that of the above- described wavelength is fully reflected by the super-conductive radiation shield 1. As the applicable super-conductive material, for example, a cubic perovskite can be applied. This material reflects light up to a relative short wave length with a critical temperature of 250 kelvin. |
