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

The energy spread measurement by use the energy spectrum analysis system at HLS LINAC now is an intercepting measurement which can't measure the real injection beam. To achieve the non-intercepting measurement, a new Beam position monitor (BPM) with eight stripline electrodes in four-axis symmetry is designed, which can measure the energy spread at HLS LINAC in real time. This paper has introduced the physical structure of this new BPM which include eight 20 degree opening angle, 1/4 wavelength (26.2mm) length Stripline electrodes in detail, analyzed and calculated the electrode response and picking up the quadrupole component, and got the theoretical sensitivities of different methods. The BPM is simulated and calculated by CST Microwave Studio Program. The results shows the parameters such as characteristic impedance, electrode coupling degree, time-domain response and frequency-domain response etc are all meet the requirement of HLS LINAC and transfer line.

• Q. Luo, J. Fang, D.H. He, B. Sun
  USTC/NSRL, Hefei, Anhui

An s-band re-entrant cavity BPM system is designed for new high brightness injector at HLS. A prototype cavity BPM system was manufactured for off-line test, which is also called cold test. According to the results of computer simulation, wire scanning off-line test method can be used to calibrate the BPM and estimate the performance of the on-line BPM system. Cross-talk problem was detected during the cold test. Ignoring nonlinear effect, transformation matrix is a way to correct cross-talk. Analysis of cold test results showed that position resolution of prototype BPM is better than 3 μm.