BEAM-PHASE MEASUREMENT SYSTEM FOR HIRFL

Abstract

The beam phase measurement system in HIRFL is<br />introduced. The system had been improved using RFsignal<br />mixing and filtering techniques and noise<br />cancellation method. Therefore, the influence of strongly<br />RF disturbing was eliminated and the signal to noise rate<br />was increased, and a stable and sensitive phase<br />measurement system was developed. The phase history of<br />the ion beam was detected by using 15 sets of capacitive<br />pick-up probes installed in the SSC cyclotron. The beam<br />phase information was necessary for tuning purposes to<br />obtain an optimized isochronous magnetic field, where<br />the beam intensity was increased and the beam quality<br />was optimized. The measurement results before and after<br />optimized isochronous magnetic field for 40Ar15+ ion and<br />12C6+ ion in SSC were given. The phase measurement<br />system was reliable by optimizing isochronous magnetic<br />field test, and the precision reached &plusmn;0.5o, the sensitivity<br />of beam signal measurement was about 10nA as well