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Plans for a VUV Science Program at the FEL. Gwyn P. Williams Free Electron Laser Jefferson Lab 12000 Jefferson Avenue Newport News, Virginia 23606. JSA Science Council January 7, 2011. Outline. Context Strategy Detailed experimental plan. JLab FEL. 4 th Generation. JLab FEL

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Plans for a VUV Science Program at the FEL

Gwyn P. Williams

Free Electron Laser

Jefferson Lab

12000 Jefferson Avenue

Newport News, Virginia 23606

JSA Science Council January 7, 2011

  • Context
  • Strategy
  • Detailed experimental plan


4th Generation



upgrade path



Average Brightness


3rd Generation

JLab THz

2nd Generation

Photon Energy (eV)


Average Brightness Landscape for Light Sources






light source





JLAB upgrade




JLab FEL VUV Opportunities



upgrade path



Average Brightness


JLab THz

VUV Ops Target

Work function of metals

Table-top laser limit

Photon Energy (eV)

real numbers
Real Numbers

- above table is for 10 eV photon energy, 0.1% bandwidth

- assumes JLab FEL at 4.7 MHz, 230 fs FWHM

real numbers more detail
Real Numbers – more detail
  • Advanced light source average brightness = 1.0 × 1017
  • HGHG average brightness = 4.1 × 1013
  • Jefferson Lab FEL average brightness = 7.5 × 1018
  • Jefferson Lab appears to have an advantage of 75, but the ALS requires a monochromator, which has a transmission of 10% at most.
  • Jefferson Lab could also increase repetition rate by factor of 16 with cryo-cooling of the optics.
  • So – potential gain of JLab FEL in near-future could be 3-4 orders of magnitude.
  • Focus on new physics for which FEL is game-changing
  • Engage with stakeholders – BES and our Science Advisory Board
  • Try to engage local or SURA universities
  • Select 3 experiments in both materials and atomic science
  • Collaborate with groups experienced in light source work
  • Use existing equipment, don’t be over ambitious
  • It is important to measure the bandwidth of our beam

Initial Science with JLab VUV FEL

1. Atom Trap Trace Analysis (ATTA).

Lu Zheng-Tian (ANL)

- nuclear physics funded

2. Combustion dynamics.

David Osborn (Sandia)

- recommended by Eric Rohlfing, BES

3. Electronic structure of correlated materials.

Peter Johnson (BNL), Z.-X. Shen (Stanford)

- co-recipients of 2011 Buckley prize


Atom Trap Trace Analysis (ATTA)

PI - Lu Zheng-Tian – Argonne National Lab

Charles Sukenik – Old Dominion University

Science – develop Kr dating.

81Kr clock is 229,000 yrs compared to C, which is 5730 yrs

Qualifications – experiment running at Argonne.

Critical application – dating the polar ice-caps.

Why FEL? – high average power can study small volumes of water.

Advantage of the experiment is that it uses FEL direct beam, without need of monochromator. The sample automatically selects the bandwidth it needs.

Implementation - Idea is to bring equipment from Argonne, and collaborate with local university user.


Atom Trap Trace Analysis (ATTA)

Schematic layout of the krypton ATTA apparatus.

Metastable krypton atoms are produced in the discharge.

The atoms are then transversely cooled, slowed and trapped by the laser

beams shown as solid arrows. The fluorescence of individual trapped atoms is

imaged to a detector. Total length of the apparatus is about 2.5 m

Courtesy Lu Zheng-Tian ANL


Chemical Dynamics

PI - David Osborne – Sandia (West) National Lab

Craig Taatjes (Sandia), Steve Leone (LBNL)

Science – new insight into chemistry by identification of reaction-intermediates using selective ionization then capture – isomeric detection is critical and new.

Qualifications: Currently running experiments at the ALS, Berkeley.

Critical Application - advanced complex fuels, new engines and pollution control.

Why FEL? – enables low cross-section species to be studied.

Advantage of the experiment is that it may be able to use FEL direct beam, without need of monochromator. The sample automatically selects the bandwidth it needs.

Implementation - bring equipment from Sandia/Berkeley


Isomeric compositionis important

+ O2 CO2 + H2O

+ O2 CO2 + H2O

+ R  PAH


Chemical Dynamics

C3H3 + C2H2 → C5H5 + C2H2

→ C7H7 . . .





Reaction studied as function of time

Courtesy Taatjes group, Sandia


Electronic Structure of Correlated Materials

PI - Peter Johnson – Brookhaven National Lab

Z.-X. Shen – Stanford University/ALS Berkeley

Science – measure electron quantum structure via photoemission.

Qualifications – already running experiments at NSLS and ALS.

Critical application – understanding novel materials such as high Tc superconductors.

Why FEL? - Higher photon energies allow access to the whole Brillouin zone, not accessible at present. 2 photons also available for pump-probe. Short pulses for time of flight detector development.

NB - This experiment will require a monochromator, which when implemented will enable many more experiments.

Implementation - bring equipment from Brookhaven.


Photoemission of Correlated Materials

Energy and momentum resolved snapshot of the electronic structure of the charge density wave

system TbTe3 at a time-delay of 200 fs after photoexcitation.

F. Schmitt et al., Science 321, 1649 (2008)]


Future Options

  • The continuation of the experimental program using what we have is subject to operating funds. Building an extended program would require us to address reliability issues.
  • Potential to increase photon flux by order of magnitude using cryo-cooled mirrors (500K).
  • Proposal already in to BES for new injector, and some operations funds to study electron beam dynamics ($10M).
  • Could engage with BES to try to get funds for re-furbished linac sections to take fundamental to 10 eV. Additional funds could take it to 100 eV.
  • Pursuing the science program will require a new program advisory committee, and we might think of a science workshop.


We continue to operate and characterize the VUV-FEL.

We are engaged with BES & several high profile users.

The present plans rely on our measured performance to date, with possibilities of considerable improvement.

the jefferson lab fel team
The Jefferson Lab FEL Team

April 24, 2009

This work supported by the Office of Naval Research, the Joint Technology Office, the Commonwealth of Virginia, the DOE Air Force Research Laboratory, The US Army Night Vision Lab, and by DOE Basic Energy & Nuclear Sciences under contract DE-AC05-060R23177.