Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams

doi:10.2172/1043865

Title: Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams

Full Record
Other Related Research

You are accessing a document from the Department of Energy's (DOE) OSTI.GOV. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service.

Visit OSTI to utilize additional information resources in energy science and technology.

Abstract

The push to provide ever brighter coherent radiation sources has led to the creation of correspondingly bright electron beams. With billions of electrons packed into normalized emittances (phase space) below one micron, collective effects may dominate both the preservation and use of such ultra-bright beams. An important class of collective effects is due to density modulations within the bunch, or microbunching. Microbunching may be deleterious, as in the case of the Microbunching Instability (MBI), or it may drive radiation sources of unprecedented intensity, as in the case of Free Electron Lasers (FELs). In this work we begin by describing models of microbunching due to inherent beam shot noise, which sparks both the MBI as well as SLAC's Linac Coherent Light Source, the world's first hard X-ray laser. We first use this model to propose a mechanism for reducing the inherent beam shot noise as well as for predicting MBI effects. We then describe experimental measurements of the resulting microbunching at LCLS, including optical radiation from the MBI, as well as the first gain length and harmonic measurements from a hard X-ray FEL. In the final chapters, we describe schemes that use external laser modulations to microbunch light sources of themore »« less

Authors:

Ratner, Daniel ^[1]

Stanford Univ., CA (United States)

Publication Date:: Sun May 01 00:00:00 EDT 2011

Research Org.:: SLAC National Accelerator Lab., Menlo Park, CA (United States)

Sponsoring Org.:: USDOE Office of Science (SC)

OSTI Identifier:: 1043865

Report Number(s):: SLAC-R-992
TRN: US1203376

DOE Contract Number:: AC02-76SF00515

Resource Type:: Thesis/Dissertation

Country of Publication:: United States

Language:: English

Subject:: 43 PARTICLE ACCELERATORS; BRIGHTNESS; COHERENT RADIATION; ELECTRON BEAMS; ELECTRONS; FREE ELECTRON LASERS; HARMONICS; INSTABILITY; LASERS; LIGHT SOURCES; LINEAR ACCELERATORS; PRESERVATION; RADIATION SOURCES; RADIATIONS; STORAGE RINGS; X-RAY LASERS; Accelerators,ACCPHY; SYNCHRAD; XFEL

Citation Formats


                    Ratner, Daniel. Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams.  United States: N. p., 2011. 
        Web.  doi:10.2172/1043865.

Copy to clipboard


                    Ratner, Daniel. Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams.  United States.  doi:10.2172/1043865.

Copy to clipboard


                    Ratner, Daniel. Sun .  
        "Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams".  United States.  doi:10.2172/1043865.  https://www.osti.gov/servlets/purl/1043865.

Copy to clipboard


                    
@article{osti_1043865,

  title        = {Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams},

  author       = {Ratner, Daniel},

  abstractNote = {The push to provide ever brighter coherent radiation sources has led to the creation of correspondingly bright electron beams. With billions of electrons packed into normalized emittances (phase space) below one micron, collective effects may dominate both the preservation and use of such ultra-bright beams. An important class of collective effects is due to density modulations within the bunch, or microbunching. Microbunching may be deleterious, as in the case of the Microbunching Instability (MBI), or it may drive radiation sources of unprecedented intensity, as in the case of Free Electron Lasers (FELs). In this work we begin by describing models of microbunching due to inherent beam shot noise, which sparks both the MBI as well as SLAC's Linac Coherent Light Source, the world's first hard X-ray laser. We first use this model to propose a mechanism for reducing the inherent beam shot noise as well as for predicting MBI effects. We then describe experimental measurements of the resulting microbunching at LCLS, including optical radiation from the MBI, as well as the first gain length and harmonic measurements from a hard X-ray FEL. In the final chapters, we describe schemes that use external laser modulations to microbunch light sources of the future. In these sections we describe coherent light source schemes for both both linacs and storage rings.},

  doi          = {10.2172/1043865},

  journal      = {},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {Sun May 01 00:00:00 EDT 2011},

  month        = {Sun May 01 00:00:00 EDT 2011}

}

Copy to clipboard

Thesis/Dissertation:

View Thesis/Dissertation

DOI: 10.2172/1043865

Other availability

Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this thesis or dissertation.

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

Investigation of Microbunching Instabilities in Modern Recirculating Accelerators

Thesis/Dissertation Tsai, Cheng

Particle accelerators are machines to accelerate and store charged particles, such as electrons or protons, to the energy levels for various scientific applications. A collection of charged particles usually forms a particle beam. There are three basic types of particle accelerators: linear accelerators (linac), storage-ring (or circular) accelerators, and recirculating accelerators. In a linac, particles are accelerated and pass through once along a linear or straight beamline. Storage-ring accelerators propel particles around a circular track and repetitively append the energy to the stored beam. The third type, also the most recent one in chronology, the recirculating accelerator, is designed tomore »« less
DOI: 10.2172/1351541

Full Text Available
Time-resolved imaging of the microbunching instability and energy spread at the Linac Coherent Light Source

Journal Article Ratner, D. ; Behrens, C. ; Ding, Y. ; ... - Physical Review Special Topics. Accelerators and Beams

The microbunching instability (MBI) is a well known problem for high brightness electron beams and has been observed at accelerator facilities around the world. Free-electron lasers (FELs) are particularly susceptible to MBI, which can distort the longitudinal phase space and increase the beam’s slice energy spread (SES). Past studies of MBI at the Linac Coherent Light Source (LCLS) relied on optical transition radiation to infer the existence of microbunching. With the development of the x-band transverse deflecting cavity (XTCAV), we can for the first time directly image the longitudinal phase space at the end of the accelerator and complete amore »« less
Cited by 11
DOI: 10.1103/PhysRevSTAB.18.030704
Reversible Seeding in Storage Rings

Conference Ratner, Daniel ; Chao, Alex ; /SLAC

We propose to generate steady-state microbunching in a storage ring with a reversible seeding scheme. High gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG) are two promising methods for microbunching linac electron beams. Because both schemes increase the energy spread of the seeded beam, they cannot drive a coherent radiator turn-by-turn in a storage ring. However, reversing the seeding process following the radiator minimizes the impact on the electron beam and may allow coherent radiation at or near the storage ring repetition rate. In this paper we describe the general idea and outline a proof-of-principle experiment. Electron storage ringsmore »« less
Full Text Available
Reversible Electron Beam Heating for Suppression of Microbunching Instabilities at Free-Electron Lasers

Journal Article Behrens, Christopher ; /DESY ; Huang, Zhirong ; ... - Physical Review Special Topics - Accelerators and Beams

The presence of microbunching instabilities due to the compression of high-brightness electron beams at existing and future x-ray free-electron lasers (FELs) results in restrictions on the attainable lasing performance and renders beam imaging with optical transition radiation impossible. The instability can be suppressed by introducing additional energy spread, i.e., heating the electron beam, as demonstrated by the successful operation of the laser heater system at the Linac Coherent Light Source. The increased energy spread is typically tolerable for self-amplified spontaneous emission FELs but limits the effectiveness of advanced FEL schemes such as seeding. In this paper, we present a reversiblemore »« less
DOI: 10.1103/PhysRevSTAB.15.022802

Full Text Available
Transverse-coherence properties of the FEL at the LCLS

Conference Ding, Yuantao ; Huang, Zhirong ; /SLAC ; ...

The recently commissioned Linac Coherent Light Source is an x-ray free-electron laser at the SLAC National Accelerator Laboratory, which is now operating at x-ray wavelengths of 20-1.2 Angstrom with peak brightness nearly ten orders of magnitude beyond conventional synchrotron sources. Understanding of coherence properties of the radiation from SASE FELs at LCLS is of great practical importance for some user experiments. We present the numerical analysis of the coherence properties at different wavelengths based on a fast algorithmusing ideal and start-end simulated FEL fields. The sucessful commissioning and operation of the linac coherent light source (LCLS) [1] has demonstrated thatmore »« less
Full Text Available

Similar Records