• G. Zinkann, E. Clifft, S.I. Sharamentov
  ANL, Argonne, Illinois

The ATLAS (Argonne Tandem Linear Accelerator System) superconducting cavities use a pneumatic system to maintain the cavity eigenfrequency at the master oscillator frequency. The present pneumatic slow tuner control has a limitation in the tuning slew rates. In some cases, the frequency slew rate is as low as 30 Hz/sec. The total tuning range for ATLAS cavities varies from 60 KHz to as high as 450 KHz depending on the cavity type. With the present system, if a cavity is at the extreme end of its tuning range, it may take an unacceptable length of time to reach the master oscillator frequency. We have designed a new slow tuner control system that increases the frequency slew rates by at least a factor of ten to a factor of three hundred in the more extreme cases. This improved system is directly applicable for use on the RIA (Rare Isotope Accelerator) cavities. This paper discusses the design of the system and the results of a prototype test.