DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Dechirper wakefields for short bunches

Journal Article · · Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
 [1];  [2]
  1. SLAC National Accelerator Lab., Menlo Park, CA (United States); SLAC STI Manager
  2. SLAC National Accelerator Lab., Menlo Park, CA (United States)

In previous work (Bane and Stupakov, 2015) general expressions, valid for arbitrary bunch lengths, were derived for the wakefields of corrugated structures with flat geometry, such as is used in the RadiaBeam/LCLS dechirper. However, the bunch at the end of linac-based X-ray FELs—like the LCLS—is extremely short, and for short bunches the wakes can be considerably simplified. In this work, we first derive analytical approximations to the short-range wakes. These are generalized wakes, in the sense that their validity is not limited to a small neighborhood of the symmetry axis, but rather extends to arbitrary transverse offsets of driving and test particles. The validity of these short-bunch wakes holds not only for the corrugated structure, but rather for any flat structure whose beam-cavity interaction can be described by a surface impedance. We use these wakes to obtain, for a short bunch passing through a dechirper: estimates of the energy loss as function of gap, the transverse kick as a function of beam offset, the slice energy spread increase, and the emittance growth. In the Appendix, a more accurate derivation—than that is found in Bane and Stupakov (2015)—of the arbitrary bunch length wakes is performed; we find full agreement with the earlier results, provided the bunches are short compared to the dechirper gap, which is normally the regime of interest.

Research Organization:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Grant/Contract Number:
AC02-76SF00515
OSTI ID:
1605006
Alternate ID(s):
OSTI ID: 1236419; OSTI ID: 22561964
Journal Information:
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Journal Name: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment Journal Issue: C Vol. 820; ISSN 0168-9002
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (11)

Wakefield potentials of corrugated structures journal October 2015
Impedance of a rectangular beam tube with small corrugations journal February 2003
Electron beam energy chirp control with a rectangular corrugated structure at the Linac Coherent Light Source journal January 2015
Using surface impedance for calculating wakefields in flat geometry journal March 2015
Calculation of wakefields in 2D rectangular structures journal October 2015
Calculation of the Cherenkov fields in the cross-section of a short relativistic bunch text January 2015
Corrugated pipe as a beam dechirper
  • Bane, K. L. F.; Stupakov, G.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 690 https://doi.org/10.1016/j.nima.2012.07.001
journal October 2012
Impedance of a Beam Tube with Small Corrugations report September 2000
Experimental Demonstration of Energy-Chirp Control in Relativistic Electron Bunches Using a Corrugated Pipe journal January 2014
Some Considerations Concerning the Transverse Deflection of Charged Particles in Radio‐Frequency Fields journal November 1956
Impedance of a Beam Tube with Small Corrugations report September 2000

Cited By (4)

Analytical treatment of the wakefields driven by transversely shaped beams in a planar slow-wave structure journal December 2018
The Impedance of Flat Metallic Plates with Small Corrugations text January 2018
Corrugated structure insertion for extending the SASE bandwidth up to 3% at the European XFEL text January 2016
Fresh-slice multicolour X-ray free-electron lasers journal October 2016