Operating experience with a superconducting magnet in a primary proton beam

Two superconducting dipole magnet modules have been operated successfully at BNL since October 1973 to bend 30 GeV/c protons from the AGS by 8° in the new North Area beam to the 7-ft. Bubble Chamber. The magnets have been energized for over 1000 hours, and, of that time, have been traversed by the proton beam with beam intensities up to 5 × 10¹²protons per pulse, for about 750 hours. Operation of these series connected magnet units, each 2 meters long at 35kG has been routine even when they were intermittently subjected to beam heating of several hundred joules per pulse due to other operational beam difficulties. Experiments were also performed where copper blocks were inserted 2 meters upstream, resulting in very large interaction rates in the beam tube inside the units. A magnet quench occurred with target thicknesses such that energy approaching 1kJ per pulse was being absorbed in the system. These are the first superconducting magnets in operation in a primary beam on which extensive radiation heating tests have been performed.