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Radiation and gas conduction heat transport across a helium dewar multilayer insulation system

Description: This report describes a method for calculating mixed heat transfer through the multilayer insulation used to insulate a 4 K liquid helium cryostat. The method described here permits one to estimate the insulation potential for a multilayer insulation system from first principles. The heat transfer regimes included are: radiation, conduction by free molecule gas conduction, and conduction through continuum gas conduction. Heat transfer in the transition region between the two gas conduction regimes is also included.
Date: October 10, 1994
Creator: Green, M.A.
Partner: UNT Libraries Government Documents Department

A superconducting linear motor drive for a positive displacement bellows pump for use in the g-2 cryogenics system

Description: Forced two-phase cooling of indirectly cooled magnets requires circulation of liquid helium through the magnet cooling channel. A bellows helium pump is one possible way of providing helium flow to a magnet cooling system. Since the bellows type of helium pump is immersed in liquid helium, a superconducting linear motor drive appears to be an attractive option. This report describes a linear motor drive that employs oriented permanent magnet materials such as samarium-cobalt as the stator magnet system and a superconducting loud speaker voice coil type of drive as the armature of the linear motor. This report examines drive motor requirements for a helium pump.
Date: October 1994
Creator: Green, M. A.
Partner: UNT Libraries Government Documents Department

A design method for multiple tube gas-cooled electrical leads for the g-2 superconducting magnets

Description: This report presents a method for designing 5300 A gas cooled electrical leads for the g-2 solenoids and 2850 A leads for the g-2 self shielded inflector dipole magnet. Empirical design equations for annular tube gas cooled leads are presented. The leads are bundled tube leads which are cooled by helium flowing in annular cooling passages between tubes. Each tube in the bundle consists of nested circular copper tubes that can be cooled on both sides. Multiple current carrying tubes will increase the lead current capacity and cooling the tubes on both sides will increase lead efficiency for a given helium flow pressure drop. The design method presented here can applied to leads made from a variety of materials.
Date: December 1, 1994
Creator: Green, M.A.; Jia, L.X.; Addessi, L.J.; Cullen, J.R. Jr.; Esper, A.J. & Meier, R.E.
Partner: UNT Libraries Government Documents Department