Performance Results of a Low Current, High Gradient Superconducting Quadrupole Magnet

A large bore, high gradient superconducting quadrupole magnet has been fabricated and tested which generates a gradient of 60 T/m in a cold bore 12.7 cm in diameter and 2.8 m long. The magnet operates safely without active quench protection and the unwanted multipole fields of the magnet sum to four parts per thousand at a bore radius of 5.0 cm. The magnet has been exposed to a neutral secondary beam at Fermilab produced by targeting a 400 GeV/c primary proton beam on a 30 cm Be target. When operated at a gradient of 52.5 T/m (86% of short sample) the magnet is quenched at a primary beam intensity of 6 x 1011 protons per one second spill. The corresponding energy deposition in the magnet coils has been calculated to be 2 mJ/cm3.