The internal bunch coordinate monitor (IBCM)

An instrument has been developed and installed at the AGS for recording the transverse motion of each rf bunch. It can be operated from any node of the Apollo control system. A preliminary version of this report has appeared elsewhere. Appendix A is an instruction manual. Two digitizers, running off the same 100 MHz clock, sampled the output of either a horizontal or vertical pick-up electrode (PUE) pair. The coordinate of each rf bunch was calculated each time it passed the PUEs during a 320 microsecond interval. Thus, the motion of each bunch could be followed during this interval. Subsequent analysis computed the Fourier transform of this motion. Bunch motion has been studied at several times during the AGS cycle: the betatron oscillations induced by the tune meter's vertical kick have been seen, and their Fourier analysis gives results consistent with the tune meter; at transition, the effect of the radial kick on each bunch has been observed; coupled-bunch oscillations have been studied; and instabilities produced by high intensities have been observed. 6 figs., 1 tab.