Phase Measurements on the ZGS 50-MeV LINAC

Abstract

Measurements of the radio-frequency phase at several points in the Argonne 50 MeV linac have been made, with and without proton beam, in an attempt to define the maximum phase changes and phase-shift rates that must be expected in the NAL 200 MeV linac. The initial results suggest that at the high-energy end of the tank a 22 mA beam produces a maximum phase shift of the order of 8° with a slope of at least 0.16 degree per microsecond. The magnitude and speed of the phase shift are both smaller as one goes farther toward the main drive loop. These results are only preliminary, as a better understanding of the effects of the rf amplitude control servo may show that it is modifying the phase performance of the system.