1. Crab Cavity Study with GDFIDL Narong Chanlek and Roger Jones 20/12/06

2. Crab Cavity Crab cavities are used for the ILC in order to increase the luminosity of the colliding beams at the interaction point. These cavities use dipole electric field to kick the bunches into a suitable angle. 20/12/06 R.M. Jones et al.,linac 2006

3. Crab Cavity TM 110 dipole mode is used to operate. Cavity shape and field structure (G. Burt and P. Goudket) 20/12/06

4. Simulation Shape of one cell model by GDFIDL GDFIDL (finite difference algorithms) is used to simulate. Higher order modes (HOMs), lower order modes (LOMs) and same order modes (SOMs) are characterized. Why do we need to simulate: - HOMs, LOMs and SOMs can also be excited in the cavity. - These mode can disrupt the bunches. 20/12/06

5. Cavity Shape Geometric parameters of the cavity shapes 20/12/06 5 cell Niobium prototype cavity Schematic view of the cavity shape

6. Results Arrow plots of E-field Monopole @ 2.75 GHz Quadupole @ 5.45 GHz dipole @ 4.10 GHz Sextupole @ 6.74 GHz 20/12/06

7. Results Dispersion diagram for single-cell Crab cavity Mode used for bunch DEFLECTION  3.9 GHz 20/12/06 Light line plot

8. Summary 20/12/06 Crab cavity uses TM 110 dipole mode to rotate the beam in order to achieve an effective collision. The frequency modes of Crab cavity are studied by GDFIDL.