CRYOGENICS FOR THE MUON G-2 SUPERCONDUCTING MAGNET SYSTEM

The g-2 muon storage ring magnet system consists of four large superco nducting solenoids that are up to 15.1 m in diameter[1,2]. In addition there is a 1.8 meter long actively shielded inflector dipole that is to guide the beam into the storage ring. The g-2 superconducting magne ts will be cooled using forced two-phase helium in tubes that is provi ded from the J-T circuit of a 625 W refrigerator. The two-phase helium flows from the refrigerator J-T circuit through a heat exchanger in a storage dewar that acts as a phase separator and a buffer for helium returning from the magnets. The g-2 magnet cooling system consists of three parallel two-phase helium flow circuits that provide cooling to: the four large superconducting solenoids, the current interconnects b etween the solenoids with the 5300 A solenoid gas cooled electrical le ads, and the inflector dipole with its 2850 A gas cooled electrical le ads.