Electrically conductive shield for refrigerator
View Patent ↗A cryogenic magnet system, comprising a cryogenic vessel ( 1 ) housing a magnet winding, a vacuum jacket ( 3 ) enclosing the cryogenic vessel and a refrigerator ( 4 ) at least partially housed within the vacuum jacket and thermally linked ( 6 ) to the cryogenic vessel. In particular, the system further comprises an electromagnetic shield.
1. A cryogenic magnet system, comprising:
a cryogenic vessel housing a magnet winding;
a vacuum jacket enclosing the cryogenic vessel; and
a refrigerator at least partially housed within the vacuum jacket; wherein,
the refrigerator comprises at least one cooling stage and a magnetic material that moves during operation of the refrigerator and is housed within a part of the refrigerator;
the system further comprises an electrically conductive shield that is thermally linked to a cooling stage of the refrigerator, and is arranged to substantially surround that part of the refrigerator which houses the magnetic material which moves; and
the electrically conductive shield is formed by a matieral that is one of aluminum, copper, and another material having similar electrical and thermal properties.
2. The cryogenic magnet system according to claim 1 , wherein the refrigerator is a two-stage refrigerator and the electrically conductive shield substantially surrounds the second stage of the refrigerator.
3. The cryogenic magnet system according to claim 1 , wherein the refrigerator is a Gifford McMahon type refrigerator, and the magnetic material is a movable regenerator.
4. The cryogenic magnet system according to claim 3 , wherein the refrigerator is a two-stage Gifford McMahon type refrigerator and the magnetic material is disposed in the second-stage of the refrigerator.
5. The cryogenic magnet system according to claim 1 , wherein:
the refrigerator is housed within a refrigerator interface sleeve;
said interface sleeve is disposed substantially within a space between the cryogen vessel and the vacuum jacket; and
the electrically conductive shield is placed on the outside of said interface shield sleeve.
6. The cryogenic magnet system according to claim 1 , wherein the cooling part of the refrigerator is exposed to the interior of the cryogen vessel.
7. The cryogenic magnet system according to claim 1 , wherein the shield material is of at least 99.999% purity.
8. The cryogenic magnet system according to claim 1 , wherein the shield comprises at least two component parts assembled into place around the refrigerator.
9. A cryogenic magnet system, comprising:
a cryogenic vessel housing a magnet winding;
a vacuum jacket enclosing the cryogenic vessel; and
a refrigerator at least partially housed within the vacuum jacket; wherein,
the refrigerator comprises at least one cooling stage and a magnetic material that moves during operation of the refrigerator, and is housed within a part of the refrigerator;
the system further comprises an electrically conductive shield that is thermally linked to a cooling stage of the refrigerator, and is arranged to substantially surround that part of the refrigerator which houses the magnetic material which moves:
the electrically conductive shield comprises at least two component parts that are assembled into place around the refrigerator; and
the at least two component parts are defined by a cut along an axial length of the shield, perpendicular to a field direction of said magnet winding.