• L.M. Gu, S.F. Lin, P. Lu, C.B. Shen, B. Sun
  USTC/NSRL, Hefei, Anhui

The stability of synchrotron radiation source is of great significance for users, and an accurate and reliable photon beam position monitor (PBPM) is essential for success of synchrotron radiation experiments. Recently, we development a new PBPM called staggered pair photon beam position monitor for photon beam position measurement in Hefei Light Source (HLS). Its main advantage is to reduce the influence of bunch size. Usually, difference over sum (Δ/Σ) method is used to process the photon beam signal. Two new methods are put forward, which are a ratio method and a log-ratio method. For photon beam with Gaussian distribution, differences among methods of Δ/Σ, ratio and log-ratio are introduced. Some calculating results are given for three signal processing methods. Comparing those three methods of position signal processing, log-ratio method is found to have the widest range of linearity, and can obtain identical beam position with different bunch size. Based on that, we also compare staggered pair monitor with double-blade monitor. The staggered pair monitor is found to have higher sensitivity, as well it can ignore the influence of bunch size.