• H. Ghasem, G.-H. Luo
  NSRRC, Hsinchu

Quadruple Bend Achromat (QBA) low emittance lattice of 3GeV Taiwan Photon Source (TPS) allows us to consider three configurations for location of a pair of superconducting transverse RF deflecting cavities for generation ultra short X-ray pulses. The available arrangements for location of cavities in a super-period of TPS are investigated. We find that use of such deflecting cavities in the middle of two QBA lattices in a super-period of TPS provides better conditions for emittance of electron beam.

• H. Ghasem, G.-H. Luo
  NSRRC, Hsinchu

Deflecting cavity generates a correlation between longitudinal position and vertical momentum of electrons in the synchrotron light sources for production short X-ray pulses. Use of such structures leads to growth in vertical amplitude and slope of stored electrons. Since errors are characteristic of real machine, any errors associated with the photon compression system must be considered and the tolerance of them must be evaluated. In this paper we present simulation of main errors due to deflecting structures, QBA lattice and injection system and find tolerances of them.

• H. Ghasem
  NSRRC, Hsinchu

A superconducting accelerating RF cavity is going to be installed in 3GeV Taiwan Photon Source (TPS). It causes a reduction in bunch length in contrast with operation of normal type of RF cavity. A higher harmonic RF cavity is usually considered as an important tool to control the bunch length in the storage rings. The harmonic cavity in lengthening mode can also be helpful for improving the lifetime which is usually dominated in the storage rings by large angle intrabeam scattering (Touschek). In this paper we study the effects of third active harmonic cavity on bunch length of the TPS ring. We present the procedure, the simulation and the formulae to analyze the effects of third harmonic cavity on the rms bunch length while the main superconducting RF system is operated in 3MV. It is shown that the longitudinal rms electron bunches will lengthen up to 7.9 times for the optimum operation of the harmonic system.

• H. Ghasem, G.-H. Luo
  NSRRC, Hsinchu

Since use of such deflecting structures leads to growth in vertical amplitude and slope of electrons, non-zero momentum compaction factor, nonlinearities and coupling of the elements between the deflectors affect the tilted electrons even in perfect machine and change their amplitude and slope at second deflecting cavity. It causes the second deflector cannot cancel the first kick perfectly and leads to increase of transverse emittance. We have studied simulation and detail analyses of effects of non-zero momentum compaction factor and sextupoles between the deflecting structures, as sources of emittance degradation in TPS and evaluate how much emittance growths due to the effects. We also contrast the statuses of interior sextupoles and elucidate them.