Design and operation of a superconducting high energy beam line at the Argonne National Laboratory zero gradient synchrotron

A superconducting high energy physics beam line 60 meters long is now operating at the Argonne National Laboratory Zero Gradient Synchrotron (ZGS). The line transports 12 GeV/c polarized protons to a large particle spectrometer. It consists of ten superconducting dipoles, two superconducting quadrupoles, and several conventional magnets. The superconducting magnets are contained in four cryostats; three 3-dipole cryostats, each 3.5 meters long; and one quad-dipole-quad (QDQ) cryostat 2.7 meters long. The superconducting magnets have a useful aperture of 7.6 cm diameter. At 12 GeV/c the dipoles operate at 2.6 T over 91 cm, with 160 amperes, and the quadrupoles at 0.31 T/cm over 41 cm, with 190 amperes. The cryostat installation, initial cooldown, boil-off gas recovery system, power supply controls, beam optics, and operating experience are presented.