Apparatus for thermal shielding of a superconducting magnet

Abstract

A thermal shield for a superconducting magnet includes a shield body having an annular shape. The shield body includes a material having a thermal conductivity greater than about 1000 W/m·K at about 70K.

1 . A thermal shield for a superconducting magnet, the thermal shield including: 
 a shield body having an annular shape and comprising a material having a thermal conductivity greater than about 1000 W/m·K at about 70K.    
   
   
       2 . The thermal shield of  claim 1 , wherein the shield body comprises a material having an electrical resitivity in a range of about 3 10-6 Ωm to about 3 10-3 Ωm.  
   
   
       3 . The thermal shield of  claim 1 , wherein the shield body comprises a material having a density less than about about 2.4 g/cm3.  
   
   
       4 . The thermal shield of  claim 1 , wherein the shield body comprises at least one of thermal pyrolitic graphite and pyrolitic boron nitride.  
   
   
       5 . The thermal shield of  claim 1 , wherein the shield body comprises: 
 a first sidewall;    a second sidewall disposed substantially parallel to the first sidewall and facing the first sidewall;    a third sidewall disposed substantially perpendicular to the first and second sidewalls and extended between corresponding edges of the first and second sidewalls; and    a fourth sidewall disposed substantially parallel to the third sidewall and extending between corresponding opposite edges of the first and second sidewalls.    
   
   
       6 . The thermal shield of  claim 5 , wherein the first, second, third and fourth sidewalls are connected to each other via mechanical joints.  
   
   
       7 . The thermal shield of  claim 6 , wherein the mechanical joints include a support ring disposed at an interior portion of each mechanical joint.  
   
   
       8 . The thermal shield of  claim 7 , wherein the mechanical joints include a high thermal conductive epoxy.  
   
   
       9 . The thermal shield of  claim 5 , wherein the first and second sidewalls each comprise a first and second sub-member.  
   
   
       10 . The thermal shield of  claim 9 , wherein the first and second sub-members are each connected via a support ring.  
   
   
       11 . The thermal shield of  claim 1 , wherein a high conductive aluminum tape is disposed at an inner surface of the thermal shield.  
   
   
       12 . The thermal shield of  claim 1 , further comprising thermal links providing thermal communication between the thermal shield and at least one of: 
 a coldhead sleeve disposed at the thermal shield; and    a penetration through the thermal shield that contains at least one of wires and instrumentation in communication with the superconducting magnet.    
   
   
       13 . A shielding system for shielding and cooling a superconducting magnet coil via a cryogen, the system comprising: 
 a cryogen vessel containing the cryogen and disposed proximate to the superconducting magnet coil to enclose the superconducting magnet coil;    a thermal shield including a shield body comprising a material having a thermal conductivity greater than about 1000 W/m·K at about 70K, the thermal shield being disposed proximate to the cryogen vessel to enclose the cryogen vessel; and    a vacuum vessel disposed proximate to the thermal shield to enclose the thermal shield.    
   
   
       14 . The system of  claim 13 , wherein the shield body comprises a material having an electrical resitivity in a range of about 3 10-6 Ωm to about 3 10-3 Ωm.  
   
   
       15 . The system of  claim 13 , wherein the shield body comprises a material having a density less than about about 2.4 g/cm3.  
   
   
       16 . The system of  claim 13 , wherein the shield body comprises at least one of thermal pyrolitic graphite and pyrolitic boron nitride.  
   
   
       17 . A thermal shield for a superconducting magnet, the thermal shield including: 
 a shield body having an annular shape; and    a cladding comprising a material having a thermal conductivity greater than about 1000 W/m·K at about 70K, the cladding being disposed at a surface of the shield body.    
   
   
       18 . The thermal shield of  claim 17 , wherein the cladding comprises a material having an electrical resitivity in a range of about 3 10-6 Ωm to about 3 10-3 Ωm.  
   
   
       19 . The thermal shield of  claim 17 , wherein the cladding comprises a material having a density less than about about 2.4 g/cm3.  
   
   
       20 . The thermal shield of  claim 17 , wherein the cladding comprises at least one of thermal pyrolitic graphite and pyrolitic boron nitride and a thickness of the cladding is selected in response to thermal gradient and average shield temperature variations.