Lattice Function Measurements in the Fermilab Accumulator Ring

The betatron phase advance between two points in a storage ring can be very accurately determined from a transverse beam transfer function measurement with DC beam. The phase advance can be determined from the difference in the phase response between an upper betatron sideband (N+Q line) and a lower betatron sideband (N-Q line) in an open loop network analyzer measurement between a kicker and a pickup. The beta functions can then be extracted from these phase measurements. This method has the advantage that it does not depend on the amplitude response of the pickup, kicker, or electronics. This technique is applied to the Fermilab Accumulator Ring to measure the betatron phase advance at 90 points around the ring, and these measurements are compared to a MAD[1] model.