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|1. (WO2018181396) CRYOGENIC FREEZER AND MAGNETIC SHIELD|
|Applicants:||SUMITOMO HEAVY INDUSTRIES, LTD.
|Title:||CRYOGENIC FREEZER AND MAGNETIC SHIELD|
A cryogenic freezer comprises: a two-stage cooling stage 72; a two-stage cylinder 51 that is provided with the two-stage cooling stage 72 on the end thereof; a two-stage displacer 52 that is provided with a magnetic cold storage material 60b and that is housed in the two-stage cylinder 51 so as to be able to reciprocate in the two-stage cylinder 51; and a magnetic shield 70 that is installed on the two-stage cooling stage 72 and that extends outside the two-stage cylinder 51 along the two-stage cylinder 51. The magnetic shield 70 is formed from a normal conductor and the product of the electric conductivity in the temperature range of 10 K or less and the wall thickness of the magnetic shield 70 is 60 MS (mega siemens) to 1980 MS inclusive.