Cryocooler and magnetic shield
AssigneeSum Itomo Heavy Industries, Ltd.
InventorsYosuke Matsumura, Takaaki Morie, Jun Yoshida
Life of this patent
Estimating the term…
Abstract
A cryocooler includes a second-stage cooling stage, a second cylinder which includes the second-stage cooling stage on a terminal of the second-stage cylinder, a second-stage displacer which includes a magnetic regenerator material and is accommodated in the second-stage cylinder so as to be able to reciprocate in the second-stage cylinder, and a tubular magnetic shield which is installed on the second-stage cooling stage and extends along the second-stage cylinder outside the second-stage cylinder. The magnetic shield is formed of a normal conductor and a product of an electrical conductivity in a temperature range of 10 K (Kelvin) or less and a thickness of the tubular magnetic shield is 60 MS (Mega-Siemens) to 1980 MS.
Claims11
A cryocooler comprising:
- a cooling stage cooled to a cryogenic temperature around or below 4.2 K;
- a cylinder which includes the cooling stage on a terminal of the cylinder;
- a displacer which includes a magnetic regenerator material and is accommodated in the cylinder so as to be able to reciprocate in the cylinder;
- and
- a tubular magnetic shield which is installed on the cooling stage and extends along the cylinder outside of the cylinder,
- wherein the tubular magnetic shield is formed of a normal conductor and a product of an electrical conductivity in a temperature range of 10 K (Kelvin) or less and a thickness of the tubular magnetic shield is formed to have a conductance of 60 MS (Mega-Siemens) to 1980 MS,
- wherein the tubular magnetic shield is formed of pure copper and cooled to the cryogenic temperature around or below 4.2 K.
A tubular magnetic shield which is directly installed on a cooling stage of a cryocooler, wherein the cooling stage cooled to a cryogenic temperature around or below 4.2 K,
- wherein the magnetic shield is formed of a normal conductor and a product of an electrical conductivity in a temperature range of 10 K (Kelvin) or less and a thickness of the tubular magnetic shield is formed to have a conductance of 60 MS (Mega-Siemens) to 1980 MS,
- wherein the tubular magnetic shield is formed of pure copper and cooled to the cryogenic temperature around or below 4.2 K.
Dependencies are inferred from the claim text.