Abstract
A corrugated structure, which is used in ``dechirper'' devices, is usually a pipe or two plates with small corrugations (bumps) on the walls. There is a good single-mode description of the wake potentials excited by a relativistic bunch if the wave length of the mode is much longer than the distance between the bumps in the pipe. However, ultrashort bunches, which are now used in free electron lasers, excite much higher frequency fields and the corresponding wake potentials will be very different from the single-mode description. We have made analyses of these wake potentials based on a numerical solution of Maxwell's equations. It was confirmed that the behavior of the wakefields of ultrashort bunches in corrugated structures is not much different from the fields excited usually in accelerating structures where the wake potentials are described by the exponential function. For a practical application we present results for the SLAC ``dechirper.'' We also carried out calculations for a similar device, that was installed and measured at the Pohang Accelerator Laboratory, Korea. We find very good agreement with the experimental results.
Highlights
The precise knowledge of the wakefields generated in different elements of free electron lasers (FEL) including accelerator, beam transport and undulators has become very important with increasing power and efficiency of x-ray production
The effect from wakefields can be “positive” if this field is used to improve the energy spectrum. These wakefields can be generated in the accelerator or in special devices—“dechirpers.” To our knowledge the word “dechirper” was first introduced in Ref. [2] where “the first experimental study was presented of a corrugated wall device that uses wake fields to remove a linear energy correlation in a relativistic electron beam.”
The wakefields in the accelerating structures are not described by a single mode. There is another description, which contains all modes, such as the Green’s function for the TeV-energy superconducting linear accelerator (TESLA) accelerating structure [6] or the Stanford Linear Accelerator Center (SLAC) accelerating structure [7] described in the following equation:
Summary
SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA (Received 20 August 2015; published 22 October 2015). There is a good single-mode description of the wake potentials excited by a relativistic bunch if the wave length of the mode is much longer than the distance between the bumps in the pipe. Ultrashort bunches, which are used in free electron lasers, excite much higher frequency fields and the corresponding wake potentials will be very different from the single-mode description. It was confirmed that the behavior of the wakefields of ultrashort bunches in corrugated structures is not much different from the fields excited usually in accelerating structures where the wake potentials are described by the exponential function. For a practical application we present results for the SLAC “dechirper.” We carried out calculations for a similar device, that was installed and measured at the Pohang Accelerator Laboratory, Korea.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Physical Review Special Topics - Accelerators and Beams
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
