J4 ›› 2011, Vol. 28 ›› Issue (5): 528-533.

• Basic Optics • Previous Articles     Next Articles

Lifetime increase using a passive higher harmonic cavity for Hefei Light SourceⅡ

LIU Guangchao, WU CongFeng, WANG Lin, FAN Hao   

  1. National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
  • Received:2010-05-27 Revised:2010-06-07 Published:2011-09-28 Online:2011-08-18
  • Supported by:

    Work is supported by the National Nature Science Foundation of china (10675116)and by Hefei Light SourceⅡProject

Abstract:

Higher harmonic cavities are used in light sources to lengthen the bunch and increase the beam lifetime without effects on beam brightness. Some longitudinal beam dynamics equations with higher harmonic cavity are derived. Calculations for Hefei Light Source II(HLS-II) with a third harmonic cavity under the optimum conditions are presented. The results show that the factor of lifetime improvement is 2.9 and the bunch length is 45.65mm. The transient beam loading effect on the bunch length in harmonic cavity may be neglected for uniform fill of all rf buckets. Meanwhile, a third harmonic cavity with higher order modes damping was optimized through a large number of simulations.

Key words: synchrotron light source, beam lifetime, higher harmonic cavity, beam loading effects, higher order modes damping

CLC Number: