Computer simulation of bunch lengthening effects caused by a third harmonic cavity in conjunction with deflecting cavities in 3 GeV Taiwan Photon Source

Abstract

The effects of utilizing a third harmonic RF cavity in thelengthening mode have been investigated by computer simulation onquality of the electron beam as well as the emitted photons in thedeflecting RF structures for TPS. For the obtained optimumsynchronous and relative harmonic phases with a harmonic voltage of0.472 MV the Touschek lifetime increases by around 8 hours. For theextreme operation mode of deflectors (h=8 and 6 MV deflectingvoltage) the eventual horizontal and vertical emittancesdramatically blows up to 3.07 nm-rad and 85 pm-rad, respectively. Inaddition, no significant difference in duration of the radiatedpulses between operation of the main and the third harmonic RFcavities is observed. The results show that the intensity of theemitted X-ray pulses with a 0.5 ps FWHM reduces by 10% for thedouble RF operation in TPS.