TY - CPAPER AU - Novokhatski, A. AU - Decker, F.-J. AU - Nosochkov, Y. AU - Sullivan, M.K. TI - The Effect of Wakefields on the FEL Performance J2 - Proc. of FEL2015 AB - If a beam travels near collimator jaws or other discontinuities of the beam pipe, it gets the energy loss and the transverse kick due to the back reaction of the beam field diffracted on the collimator's jaws. The wake field effect from collimators may not only bring an additional energy jitter and change the trajectory of the beam, but may also lead to degradation of the performance of Free Electron Laser (FEL) It may be possible due to the special character of the wake fields: the response reaction depends on the longitudinal position of the particles in the bunch. We describe a model of the wake field radiation, simulation results and comparison with measurements. PB - JACoW CY - Geneva, Switzerland SP - 161 EP - 165 KW - emittance KW - wakefield KW - linac KW - FEL KW - undulator DA - 2015/12 PY - 2015 SN - 978-3-95450-134-2 DO - 10.18429/JACoW-FEL2015-MOP055 UR - http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/mop055.pdf ER -