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Title: Measurements of wake-induced electron beam deflection in a dechirper at the Linac Coherent Light Source

Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1380153
Report Number(s):
SLAC-PUB-17121
DOE Contract Number:
AC02-76SF00515
Resource Type:
Program Document
Country of Publication:
United States
Language:
English

Citation Formats

None. Measurements of wake-induced electron beam deflection in a dechirper at the Linac Coherent Light Source. United States: N. p., 2017. Web.
None. Measurements of wake-induced electron beam deflection in a dechirper at the Linac Coherent Light Source. United States.
None. 2017. "Measurements of wake-induced electron beam deflection in a dechirper at the Linac Coherent Light Source". United States. doi:. https://www.osti.gov/servlets/purl/1380153.
@article{osti_1380153,
title = {Measurements of wake-induced electron beam deflection in a dechirper at the Linac Coherent Light Source},
author = {None},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 8
}

Program Document:
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  • The RadiaBeam/SLAC dechirper, a structure consisting of pairs of flat, metallic, corrugated plates, has been installed just upstream of the undulators in the Linac Coherent Light Source (LCLS). As a dechirper, with the beam passing between the plates on axis, longitudinal wakefields are induced that can remove unwanted energy chirp in the beam. However, with the beam passing off axis, strong transverse wakes are also induced. This mode of operation has already been used for the production of intense, multicolor photon beams using the fresh-slice technique, and is being used to develop a diagnostic for attosecond bunch length measurements. Heremore » we measure, as a function of offset, the strength of the transverse wakefields that are excited between the two plates, and also for the case of the beam passing near to a single plate. We compare with analytical formulas from the literature, and find good agreement. As a result, this report presents the first systematic measurements of the transverse wake strength in a dechirper, one that has been excited by a bunch with the short pulse duration and high energy found in an x-ray free electron laser.« less
  • The Linac Coherent Light Source (LCLS), currently under design, requires beam diagnostic instruments between the magnets in the beam undulator section. Ten wire scanners are planned as one of the primary instruments to characterize electron beam properties. The development of these wire scanners presents several design challenges due to the need for high accuracy and resolution of the wire motion (3-{micro}m tolerance, typical) and the high intensity of the beam (1 nC, 3400-A peak, over an area of 30-{micro}m rms radius at 120 Hz). In this paper, we present the technical specification and design criteria for the scanners. We willmore » also present the mechanical design of the UHV-compatible drive and its engineering analysis. Lastly, we present the wire card design and discuss associated thermal and mechanical issues originating from the highly intense x-ray and electron beams.« less
  • The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) based on the final kilometer of the Stanford Linear Accelerator. The tight tolerances for positioning the electron beam close to the undulator axis calls for the introduction of Beam Finder Wire (BFW) device. A BFW device close to the upstream end of the undulator segment and a quadrupole close to the down stream end of the undulator segment will allow a beam-based undulator segment alignment. Based on the scattering of the electrons on the BFW, we can detect the electron signal in the main dump bends aftermore » the undulator to find the beam position. We propose to use a threshold Cherenkov counter for this purpose. According to the signal strength at such a Cherenkov counter, we then suggest choice of material and size for such a BFW device in the undulator.« less