Offline calibration of stripline beam position monitor for HLS Ⅱ

A stripline beam position monitor(BPM) was designed for HLS Ⅱupgraded and used to measure beam parameter in the HLS storage ring. Position signal was offline calibrated using the difference/sum and log-ratio methods. Sensitivities, mapping figures and experienced fitting polynomials were acquired. The results showed that the sensitivities and linear range using logratio method were bigger than those using difference/sum method. The sum signal was offline calibrated and the result showed that the variety of normalized sum signal relative to the sum signal at the stripline BPM center was no more than 6 % in the range of (-5 mm, -5 mm) to (5 mm, 5 mm). The stripline BPM will be also used to measure the transverse quadrupole oscillation in the HLS storage ring, so calibrating transverse quadrupole component is needed. The Gaussian weighted method of a two-dimensional grid structure was used to simulate the Gaussian bunch and the difference/sum method was applied to calculate transverse quadrupole component. The measurement result was compared with the simulation result. The result showed that the sensitivity of the transverse quadrupole component varying with (x2-y2) by offline method was the same as simulation result and sensitivity was 0.001 1 mm-2. Experienced fitting polynomial was calculated to be used for the future online measurement.