Abstract: Materials for cryogenic refrigerator regenerators are formed by a high yield spark erosion cell. The materials are made of erbium or dysprosium and are spherical shaped. The spheres have a diameter range of 150 .mu.m to 400 .mu.m with a packing factor of at least 50%. The materials are made by disposing chunks of a starting material into a liquid dielectric in a spark chamber, agitating the chunks, impressing a spark voltage in order to cause melting of the chunks and formation of spherical particles, and collecting the particles at the bottom of the spark chamber. The particles may then be gathered, dried, and separated.

Abstract: A superconductive magnet having at least one superconductive coil is provided. A thermal radiation shield is situated inside a vacuum vessel and the thermal radiation shield encloses the superconductive coil. A thermal diode is provided for thermally linking the superconductive coil and the thermal radiation shield when the thermal radiation shield is colder than the superconductive coil.

Abstract: A cryorefrigerator mount for a refrigerated superconductive magnet is disclosed. In particular, a cryorefrigerator system has two separate cryorefrigerators such that one of the cryorefrigertors contacts and cools the magnet while the other cryorefrigerator is held in a raised, standby position. If the first cryorefrigerator malfunctions and can no longer cool the magnet, the second cryorefrigerator is lowered to contact and cool the magnet. The first cryorefrigerator is then raised so it can be repaired, serviced or replaced.

Abstract: A Gifford-McMahon cryorefrigerator is modified by using opposed sub-displacers which are sinusoidally reciprocated in opposite directions with respect to one another such that the force vectors of inertia created by the movement of the sub-displacers are cancelled out. The cancelling out of the force vectors should substantiallly reduce adverse affects associated with displacer banging.

Abstract: A two-stage harmonic reciprocating Stirling engine has a primary heater and a pair of regenerators with an intermediate heat exchanger disposed in the fluid flow between the two regenerators. High temperature heat above 5000.degree. F. is supplied to the heater head of the engine while lower temperature, otherwise wasted, heat between 500.degree. F. and 1500.degree. is supplied to the intermediate heat exchanger. The lower temperature heat can be from exhaust gases of the primary burner, or can be waste heat from another process for use in a cogeneration installation.