• Q. Luo, H. He, P. Li, P. Lu, B. Sun, J. H. Wang
  USTC/NSRL, Hefei, Anhui

For the development of accelerators we require increasingly precise control of beam position. Cavity BPMs promise a much higher position resolution compared to other BPM types and manufacture of cavity BPMs is in general less complicated. The cavity BPM operating at S-band for HLS (Hefei Light Source) was designed. It consists of two cavities: a position cavity tuned to TM110 mode and a reference cavity tuned to TM010 mode. To suppress the monopole modes we use waveguides as pickups. Superheterodyne receivers are used in electronics for many cavity BPMs while we decide to use chip AD8302 produced by Analog Devices to process the signals. To simulate and calculate the electromagnetic field we use MAFIA.

• B. Y. Wang, P. Lu, B. Sun, J. Wang, J. H. Wang, H. Xu
  USTC/NSRL, Hefei, Anhui

A simple measurement method of beam bunch length in time domain for HLS (Hefei Light Source) has been proposed. The Bunch length measurement system is composed of an optical system, a high speed photo-receiver and a wide bandwidth oscilloscope. The photo-receiver which is made by FEMTO has high sensitivity and high bandwidth, which converts the synchrotron radiation light into electronic signal. The oscilloscope which is made by Tektronix is TDS7704B, which has a high bandwidth up to 7GHz and show the bunch length in time domain. The measurement results of the bunch length and its analysis are given. We compare the results with that determined by the conventional method using a streak camera.