Basic Energy Science Workshop

on
Future Electron Sources

Workshop Co-Organizers

Pietro Musumeci (UCLA) & Xijie Wang (SLAC)

DOE BES contact: Eliane Lessner

Workshop charge

Electron sources representa critical enablingtechnologyfor cutting-edge applications of electron accelerators. The development of high-brightness electron sources led to the success of X-ray free electron laser (FEL), which has changed the paradigm for many areas of science, such as imaging single nano-scale particles and understanding chemistry on the natural timescales of reactions. The introduction of cold field emitter electron sources and aberration correction optics made it possible for electron microscope to achieve sub-Å spatial resolution. Breakthrough advances in electron sources are required for future X-ray and electron instruments. DOE BES will sponsor a Workshop on Future of Electron Sources September 8th and 9th 2016 to be held at SLAC National Accelerator Laboratory. The Workshop will explore the frontier of electron source R&D with the following goals:

•Identify needs and opportunities for research in novel electron sources

•Seek for transformational advances in peak and average electron beam brightness to enable and expand scientific capabilities of X-ray and electron scatteringinstruments.

•Explore enabling novel applications such as shorter wavelength FELs, single shot UEM, fs-nanodiffraction, high average flux Compton, compact light sources, etc.

Workshop Format

•0.5 plenary talks

•1.5 days working groups + report writing

•65 people attendance, participantsfrom the following:

•15 people representing US Universities: ASU, Cornell, Michigan State, MIT, Stanford University, NIU,UCLA,

•National Laboratory: ANL, BNL, LBNL, LANL,LLNL, SLAC, JLAB

•International: China (1), Japan (2), Europe (4)

•DOE: BES(2), HEP (1), NP(1)

Plenary Talks

•Workshop charge and electron source research overview at DOE (E. Lessner/J. Murphy)

General idea behind workshop. Motivation. DOE BES interest

•High brightness electron sources (I. Bazarov)

Status of electron source research. Quantum limit of beam brightness. Regimes of operation of photoinjectors.

•Future Needs of Electron Source for X-ray FEL (P. Emma)

Electron source needs; X-ray FEL oscillator and amplifiers(LCLS2 and Marie). Performance tradeoffs

•Future Need of Electron Source for Electron Scattering Instrumentation (D. Muller)

Opportunities in ultrafast electron diffraction and ultrafast electron microscopy. Parameter list for ideal source for electron scattering instrumentation.

•Novel electron sources(S. Chattopadhyay)

Advanced concepts. Source needs for Compton applications/Plasmas source

PANELS

Panel # 1: Science and technology of electron generation

Panel Leaders: K. Harkayand A. Fry

  • Can the thermal emittance be reduced by orders of magnitude?
  • Where can we expect significant improvements in QE + thermal emittance + lifetime performances?
  • Laser and optics shaping for future electron sources.
  • Characterization and off-line diagnostics of photocathode properties

Panel #2: CW electron source

Panel Leaders: B. Dunham and J. Sekutowicz

  • What is mainly limiting the brightness of CW injectors?
  • How do SRF, DC and VHF gun compare? What is the ideal application for each?
  • Can we satisfy the stability, timing and synchronization demands?
  • Characterization of electron sources and novel beam diagnostics (low charges, ultra-small emittance, ultrashort pulse lengths)

Panel # 3: Pulsed injectors

Panel Leaders: B. Carlsten and J. Power

  • What is the effect of higher extraction field on the beam brightness?
  • What are the novel ideas to push the performances of these devices?
  • Simulations and modeling (space charge, disorder induced heating)
  • Can we satisfy the stability, timing and synchronization demands?
  • Characterization of electron sources and novel beam diagnostics (low charges, ultra-small emittance, ultrashort pulse lengths)

Panel # 4: Exotic sources: Cold atoms, plasma-based, tips, THz guns

Panel Leaders: P. Piot andC. Schroeder

  • How far from prime-time are exotic sources?
  • Field emission sources
  • Which one is most promising given the range of applications for BES
  • Identify the first applications where some of these sources will make an impact.
  • Are simulations and modeling tool adequate?
  • Characterization of electron sources and novel beam diagnostics (low charges, ultra-small emittance, ultrashort pulse lengths)

Panelists

Preliminary list

WG1 Physics of photoemission

K. Harkay, A. Fry, H. Padmore, L. Cultrera, N. Moody, J. Smedley, A. Schroeder, K. Jensen, M. Babzien, F. Hannon, S. Karkhare,T. Vecchione, F. Sannibale

WG2 CW electron sources

B. Dunham, J. Sekutowicz, D. Filippetto, I. Bazarov, C. Hernandez Garcia,M.Yamamoto,W. Wan, A. Minor, R. K. Li, J. Frisch, J. Lewellen, D. Flannigan,J. Qiang, D. Muller

WG3 Pulsed electron guns

B. Carlsten, J. Power, M. Berz, J. B. Rosenzweig, K.J. Kim, Y. Zhu, J. Maxson, C. Limborg,S. J. Russell, T. Shintake,F. Zhou,M. Ferrario, P. Emma

WG4 Novel sources

P. Piot, C. Schroeder,M. Chen, W.Graves, B. Barwick,E. Nanni, M. Fuchs, W. Gai, J. Van Tilborg, J. Wu, F. Albert, H. Andrews, M. B. Raschke, P. Baum,K. More, S. Chattopadhyay

Note:

Boldworking group lead

Green from US University

Red oversea participants

Italic Plenary speaker