A 1.8 T dipole magnet using thin grain oriented silicon steel laminations has been constructed as a prototype for a muon synchrotron ramping at 400 Hz. Following the practice in large 3 phase transformers and our own Opera-2d simulations, joints are mitred to take advantage of the magnetic properties of the steel which are much better in the direction in which the steel was rolled. Measurements with a Hysteresigraph 5500 and Epstein frame show a high magnetic permeability which minimizes stored energy in the yoke allowing the magnet to ramp quickly with modest voltage. Coercivity is low which minimizes hysteresis losses. A power supply with a fast Insulated Gate Bipolar Transistor (IGBT) switch and a capacitor was constructed. Coils are wound with 12 gauge copper wire. Thin wire and laminations minimize eddy current losses. The magnetic field was measured with a peak sensing Hall probe.
@article{arxiv.1207.6730,
title = {Test of a 1.8 Tesla, 400 Hz Dipole for a Muon Synchrotron},
author = {D. J. Summers and L. M. Cremaldi and T. L. Hart and L. P. Perera and M. Reep and H. Witte and S. Hansen and M. L. Lopes and J. Reidy,},
journal= {arXiv preprint arXiv:1207.6730},
year = {2012}
}