2012/04/02 by I.R.R. Shinton, Shinton, Ian Reginald Roy, Nawin Juntong +1 · 1 citation
Engineering · Physics and Astronomy · #Particle Accelerators and Free-Electron Lasers #Particle accelerators and beam dynamics #Gyrotron and Vacuum Electronics Research
paper · pdf · doi:10.48550/arxiv.1204.0391
The resonant modes in the 9cell 3.9GHz bunch shaping cavity designed by\nFERMILAB in collaboration with DESY [1] and installed in FLASH at DESY were\ncalculated up to the range of 10GHz in terms of the band structure of this\ndesign. The modal nature of this structure has previously been investigated by\nvarious parties [1]. We have extended this work to include a modal pictorial\ndictionary in which the nature of the modes can be readily identified as well\nas the R/Q's for each of the modes. Below 10GHz only monopole, dipole,\nquadrupole and sextupole bands exist for this particular structure. Herein we\nonly consider the modal patterns of the bands themselves and have not included\nthe beampipe modes in the pictorial dictionary. The R/Q definition that we use\nis that of [2]. In addition to the finite element simulations we also utilise a\ncapacitive-inductive circuit model to achieve a rapid characterisation of the\ncavity.\n