Observation and Analysis of Static Deflections from ~ansverse Long-Range Wakefields in the SLC*

In the SLC main linac a train of three bunches is accelerated. The leading positron bunch is followed by two bunches of electrons. When the positron bunch passes off-mis through the RF structures, it excites dipole modes in the struttures, for example long-range transverse wakefields which deflect the subsequent electron bunches. Although the magnitude of the deflections is small one can infer the deflections by measuring the trajectory difference while changing the spacing between the positron and electron bunches. Knowing the positron trajectory the rnisalignrnents of the accelerating RF structures with respect to the -BPM’s can be calculated. We present measurements from the SLC linac and discuss the data analysis and errors. Presented at the 17th IEEE Particle Accelerator Conference (PAC 97): Accelerator Science, Technology and Applications, Vancouver, B. C., Canada, May 12–16, 1997 *Work supported by Dep=tment of Energy contract DE-AC03-76SFO0515. OBSERVATION AND ANALYSIS OF STATIC DEFLECTIONS FROM TRANSVERSE LONG-RANGE WAKEFIELDS IN THE SLC* R.W. Assmann, F.J. Decker, P. Raimondi, T.O. Raubenheimer Stanford Linear Accelerator Center, Stanford University, Stanford, CA 94309