Superconducting magnet with re-entrant tube suspension resistant to buckling

A superconductive magnet comprising:

• a) a generally longitudinally extending axis;
• b) a generally annularly-cylindrical-shaped vacuum enclosure generally coaxially aligned with said axis;
• b) a generally annularly-cylindrical-shaped thermal shield generally coaxially aligned with said axis and disposed within and spaced apart from said vacuum enclosure;
• c) a generally solenoidal-shaped superconductive coil generally coaxially aligned with said axis and disposed within and spaced apart from said thermal shield;
• and
• d) a magnet re-entrant support assembly including:
• (1) a generally annularly-cylindrical-shaped outer support cylinder generally coaxially aligned with said axis, disposed within and generally spaced apart from said vacuum enclosure, disposed outside and generally spaced apart from said thermal shield, having a first end rigidly connected to said vacuum enclosure, and having a second end rigidly connected to said thermal shield;
• (2) a generally annularly-cylindrical-shaped inner support cylinder generally coaxially aligned with said axis, disposed within and generally spaced apart from said thermal shield, disposed outside and generally spaced apart from said superconductive coil, having a first terminus rigidly connected to said thermal shield proximate said second end of said outer support cylinder, and having a second terminus disposed longitudinally between said first and second ends of said outer support cylinder and rigidly connected to said superconductive coil;
• and
• (3) a first stiffening ring having a value of Young's modulus which is at least equal to generally the value of Young's modulus for one of said outer and inner support cylinders, said first stiffening ring generally coaxially aligned with said axis and attached to said one of said outer and inner support cylinders longitudinally between said first and second ends of said one of said outer and inner support cylinders.