New measurements of magnetic field decay in 1 meter SSC-type dipoles

Previous studies of magnetic field decay in model SSC (Superconducting Super Collider) dipoles due to changes in magnetization currents caused by flux creep have used the assumed SSC injection energy of 1 TeV, or an 0.33-T central dipole field, and an excitation to the storage field of 6.6 T. More recently, it has been decided to inject at 2 TeV, or 0.66 T and so more recent tests have been carried out at the new injection field, or at both the new and old fields. Additionally, the effects of temperature changes and excitation cycles on the field decay have been studied. The roughly log linear decay of magnetization current multipole fields has been demonstrated in several new dipoles. A suggested mechanism of thermally induced activation in the additional 0.5-K range has been effectively countered by temperature measurements that show temperature fluctuation ten to thirty times lower, over a 90-min time period.