FEL2014 - List of Authors (Bane, K.L.F.)

Paper	Title	Page
THP026	Design Study of LCLS Chirp-Control with a Corrugated Structure	748
	Z. Zhang, K.L.F. Bane, Y. Ding, Z. Huang, R.H. Iverson, T.J. Maxwell, G.V. Stupakov, L. Wang SLAC, Menlo Park, California, USA P. Frigola, M.A. Harrison, M. Ruelas RadiaBeam, Marina del Rey, California, USA
	The purpose of this paper is to investigate the use of flat metallic plates with small corrugations as a passive dechirper, studying its effects on beam dynamics. Similar systems have been tested in Pohang and Brookhaven at relatively low energies (~100 MeV) and with relatively long bunches (>1ps) [,]. Four meters of such a structure are being machined by Radiabeam Systems for use in the LCLS with a high energy and femtosecond electron beam. In this paper we use a field matching program to obtain the longitudinal and transverse wakes for the purpose of the LCLS dechirper design. In addition, we fit the longitudinal wake to simple functions, so that one can obtain the wake without resorting to the field matching program. Since the transverse wakes–both dipole and quadrupole wakes–are strong, we include beam dynamics simulations to find the tolerances for injection jitter and misalignment in the LCLS. P. Emma, et al. PRL 112, 034801 ** M. Harrison, et al., NaPAc 2013, Pasadena, USA

THP031	Further Understanding the LCLS Injector Emittance	774
	F. Zhou, K.L.F. Bane, Y. Ding, Z. Huang, H. Loos SLAC, Menlo Park, California, USA
	Funding: US DOE under contract No. DE-AC02-76SF00515 Notable COTR effect from the LCLS laser heater chicane is recently observed at the LCLS injector OTR screen, used for routine emittance measurements. The emittance with the OTR screen is under-estimated by about 30% compared to the values with the wire scanner located next to the OTR screen. The emittance with the OTR and wire scanner is compared and relevant analyses are presented. Slice emittance upstream of the LCLS BC1 is measured using a traditional transverse cavity. Recently, slice emittance downstream of the BC1 is able to be measured with a newly developed technique, using a collimator located in the middle of the BC1. The parasitic effects of using the collimator for slice emittance measurement are evaluated. The slice emittance before and after the BC1 is compared. The dependence of the slice emittance on the linearizer’s transverse offset and CSR effect from the BC1 is discussed.

Paper

Title

Page

Design Study of LCLS Chirp-Control with a Corrugated Structure

748

Z. Zhang, K.L.F. Bane, Y. Ding, Z. Huang, R.H. Iverson, T.J. Maxwell, G.V. Stupakov, L. Wang
SLAC, Menlo Park, California, USA
P. Frigola, M.A. Harrison, M. Ruelas
RadiaBeam, Marina del Rey, California, USA

The purpose of this paper is to investigate the use of flat metallic plates with small corrugations as a passive dechirper, studying its effects on beam dynamics. Similar systems have been tested in Pohang and Brookhaven at relatively low energies (~100 MeV) and with relatively long bunches (>1ps) [*,**]. Four meters of such a structure are being machined by Radiabeam Systems for use in the LCLS with a high energy and femtosecond electron beam. In this paper we use a field matching program to obtain the longitudinal and transverse wakes for the purpose of the LCLS dechirper design. In addition, we fit the longitudinal wake to simple functions, so that one can obtain the wake without resorting to the field matching program. Since the transverse wakes–both dipole and quadrupole wakes–are strong, we include beam dynamics simulations to find the tolerances for injection jitter and misalignment in the LCLS.
* P. Emma, et al. PRL 112, 034801
** M. Harrison, et al., NaPAc 2013, Pasadena, USA

THP031

Further Understanding the LCLS Injector Emittance

774

F. Zhou, K.L.F. Bane, Y. Ding, Z. Huang, H. Loos
SLAC, Menlo Park, California, USA

Funding: US DOE under contract No. DE-AC02-76SF00515
Notable COTR effect from the LCLS laser heater chicane is recently observed at the LCLS injector OTR screen, used for routine emittance measurements. The emittance with the OTR screen is under-estimated by about 30% compared to the values with the wire scanner located next to the OTR screen. The emittance with the OTR and wire scanner is compared and relevant analyses are presented. Slice emittance upstream of the LCLS BC1 is measured using a traditional transverse cavity. Recently, slice emittance downstream of the BC1 is able to be measured with a newly developed technique, using a collimator located in the middle of the BC1. The parasitic effects of using the collimator for slice emittance measurement are evaluated. The slice emittance before and after the BC1 is compared. The dependence of the slice emittance on the linearizer’s transverse offset and CSR effect from the BC1 is discussed.