Operating Experience with the Cryogenic Systems for a Superconducting Cyclotron

The successful operation of the superconducting cyclotron cryogenic system has been primarily dependent on understanding and improving its performance. In particular, operating experience with a superconducting magnet coil, a vacuum cryopanel, and a cryogenic distribution system has been gained during the past three years. The coil cryostat cooldown, boiloff rate, warmup, eddy current pulse, median plane heat leak, and helium leakage into the cryostat vacuum jacket have been measured. The vacuum cryopanel cooldown rate, heat load, pumping speed and long term gas storage have been determined. The present measurements have been conducted with simple independent transfer lines. A subcooled cryogenic distribution system, with parallel branches, has been designed and is presently under construction.