A prototype superconducting insertion quadrupole magnet for TRISTAN

An iron-free superconducting quadrupole with a 140 mm coil inner diameter and a field gradient of 70 T/m has been built and tested as a prototype magnet for use in low beta insertions of the TRISTAN Main Ring. The magnet is made from 27 strands of NbTi Rutherford type cable clamped with stainless steel collars. A maximum field gradient of 80 T/m with a peak field of 6.0 T in the coil was obtained after five quenches. Quench characteristics and field gradient homogeneity of this quadrupole were studied in a vertical cryostat. Mechanical disturbance energies in the coil were also obtained from measurements of the voltages across the coil