This paper describes a detector magnet which returns flux between the coils rather than through an iron return path. This actively shielded, uniform field 2 T magnet can be fabricated in separate parts which can be manufactured on the SSC site. This magnet can be built so that central field is uniform enough to permit a TPC detector to be used without iron poles. The field outside of the coil can be made to fall of as R−N power where N approaches 9. A major advantage of the magnet described in the paper is that there is no pole piece to block the particle jets emanating from the collision region in the forward and backward directions. Inexpensive materials such as earth and concrete can be used to provide the mass needed to analyze particles such as mu mesons. As a result, problems such as experimental hall subsidence can be reduced. Perhaps the cost of such an experiment can also be reduced. This type of magnet would require experimenters to rethink their experimental concepts.

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A Large Superconducting Detector Magnet Without An Iron Return Path

Helium Cooling Systems for Large Superconducting Physics Detector Magnets

This paper describes the cryogenic tests of the TPC 2-meter-diameter superconducting solenoid on a 200 W refrigerator with gas-bearing turbines. The solenoid is cooled with two phase helium in forced flow around the superconducting winding. The two-phase helium was circulated using either the J-T circuit flow or a bellows type liquid helium pump. The particular problems associated with running a variable load on a gas-bearing turbine refrigerator are discussed.

/pdf/forced-two-phase-cooling-of-the-tpc-superconducting-solenoid-3a8alnjb4w.pdf

Forced Two-Phase Cooling of the TPC Superconducting Solenoid

/pdf/cryogenic-testing-of-the-tpc-superconducting-solenoid-26g4cd50ug.pdf

H. Petersen

Papers

Cryogenic testing of the TPC superconducting solenoid