RF systems engineering for the SSC collider rings

Acceleration and storage of 70-mA proton beams in the 2×20 TeV Supercollider rings can be performed both with normal conducting as well as superconducting 360-MHz RF systems. A normal conducting accelerating structure would use 32 or 24 single-cell cavities per ring, operating with a mean gradient of 2-2.6 MV/m to generate the required peak voltage of 20 MV in the beam holding mode. Superconducting cavities would allow operation with mean gradients up to about 5 MV/m, and tolerate higher transient beam loading due to nearly tenfold larger stored energy in the accelerating structure. A superconducting structure could consist of five pairs of single-cell resonators per ring, each pair being fed by a 250-kW CW klystron amplifier. The use of 500-kW or 250-kW klystron amplifiers, six or eight per ring, would seem appropriate for feeding normal conducting structures. Provisions for feedforward and feedback (RF amplitude and phase) are included in the low-level RF system. Furthermore, active damping of undesired modes and corrections of bunch phase deviations are planned by means of auxiliary (broadband) RF systems