Calculating the Loss factor of the LCLS Beam Line Elements for Ultra-Shrot Bunches
Abstract
The Linac Coherent Light Source (LCLS) is a SASE 1.5-15 {angstrom} x-ray Free-Electron Laser (FEL) facility. Since an ultra-short intense bunch is used in the LCLS operation one might suggest that wake fields, generated in the vacuum chamber, may have an effect on the x-ray production because these fields can change the beam particle energies thereby increasing the energy spread in a bunch. At LCLS a feedback system precisely controls the bunch energy before it enters a beam transport line after the linac. However, in the transport line and later in the undulator section the bunch energy and energy spread are not under feedback control and may change due to wake field radiation, which depends upon the bunch current or on a bunch length. The linear part of the energy spread can be compensated in the upstream linac; the energy loss in the undulator section can be compensated by varying the K-parameter of the undulators, however we need a precise knowledge of the wake fields in this part of the machine. Resistive wake fields are known and well calculated. We discuss an additional part of the wake fields, which comes from the different vacuum elements like bellows, BPMs, transitions, vacuummore »
- Authors:
- Publication Date:
- Research Org.:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC)
- OSTI Identifier:
- 1046948
- Report Number(s):
- SLAC-PUB-13775
TRN: US1203809
- DOE Contract Number:
- AC02-76SF00515
- Resource Type:
- Conference
- Resource Relation:
- Conference: Contributed to the 31st Free Electron Laser Conference, Liverpool, United Kingdom, 23-28 Aug 2009
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 43 PARTICLE ACCELERATORS; BEAM TRANSPORT; FEEDBACK; FREE ELECTRON LASERS; LIGHT SOURCES; LINEAR ACCELERATORS; PRODUCTION; TRANSPORT; VALVES; WIGGLER MAGNETS; Accelerators,ACCPHY, XFEL
Citation Formats
Novokhatski, A, and /SLAC. Calculating the Loss factor of the LCLS Beam Line Elements for Ultra-Shrot Bunches. United States: N. p., 2009.
Web.
Novokhatski, A, & /SLAC. Calculating the Loss factor of the LCLS Beam Line Elements for Ultra-Shrot Bunches. United States.
Novokhatski, A, and /SLAC. 2009.
"Calculating the Loss factor of the LCLS Beam Line Elements for Ultra-Shrot Bunches". United States. https://www.osti.gov/servlets/purl/1046948.
@article{osti_1046948,
title = {Calculating the Loss factor of the LCLS Beam Line Elements for Ultra-Shrot Bunches},
author = {Novokhatski, A and /SLAC},
abstractNote = {The Linac Coherent Light Source (LCLS) is a SASE 1.5-15 {angstrom} x-ray Free-Electron Laser (FEL) facility. Since an ultra-short intense bunch is used in the LCLS operation one might suggest that wake fields, generated in the vacuum chamber, may have an effect on the x-ray production because these fields can change the beam particle energies thereby increasing the energy spread in a bunch. At LCLS a feedback system precisely controls the bunch energy before it enters a beam transport line after the linac. However, in the transport line and later in the undulator section the bunch energy and energy spread are not under feedback control and may change due to wake field radiation, which depends upon the bunch current or on a bunch length. The linear part of the energy spread can be compensated in the upstream linac; the energy loss in the undulator section can be compensated by varying the K-parameter of the undulators, however we need a precise knowledge of the wake fields in this part of the machine. Resistive wake fields are known and well calculated. We discuss an additional part of the wake fields, which comes from the different vacuum elements like bellows, BPMs, transitions, vacuum ports, vacuum valves and others. We use the code 'NOVO' together with analytical estimations for the wake potential calculations.},
doi = {},
url = {https://www.osti.gov/biblio/1046948},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Oct 17 00:00:00 EDT 2009},
month = {Sat Oct 17 00:00:00 EDT 2009}
}