Ultrabright Laser-based MeV-class Light Source Page: 3 of 4
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
Ultrabright Laser-based MeV-class Light Source
F. Albert, G. Anderson, S. Anderson, A. Bayramian, B. Berry, S. Betts, J. Dawson, C. Ebbers, D. Gibson,
C. Hagmann, J. Hall, F. Hartemann, E. Hartouni, J. Heebner, J. Hernandez, M. Johnson, M. Messerly,
D. McNabb, H. Phan, J. Pruet, V. Semenov, M. Shverdin, A. Sridharan, A. Tremaine,
C.W. Siders, C.P.J. Barty
Lawrence Livermore National Laboratory
7000 EastAvenue, L-470, Livermore CA 94550
bartvI llnl.gov
Abstract: We report first light from a novel, new source of 10-ps 0.776-Me V gamma-ray pulses
known as T-REX (Thomson-Radiated Extreme X-rays). The MeV-class radiation produced by T-
REX is unique in the world with respect to its brightness, spectral purity, tunability, pulse duration
and laser-like beam character. With T-REX, one can use photons to efficiently probe and excite
the isotope-dependent resonant structure of atomic nucleus. This ability will be enabling to an
entirely new class of isotope-specific, high resolution imaging and detection capabilities.
Laser based Thomson or Compton scattering based gamma-ray light sources are the path to ultrahigh brightness
tunable light sources above 100-keV. For head-on collisions, the peak brightness of Compton scattering light
sources, scaling inversely with the electron pulse duration, linearly as the number of electrons and laser photons, and
as the square of the e-beam emittance, is ideal for ultrahigh brightness gamma ray generation [1]. In contrast to
previous efforts, which have either been low energy [2, 3] or recirculating [4], this effort simultaneously optimizes
the electron beam energy spectrum and emittance as well as the laser bandwidth and focusing to generate ultrabright
(>10" photons/sec/mm2/mrad2/0.1%BW), monochromatic (<1%), and highly directional (mrad) gamma rays near 1-
MeV.
We have demonstrated 106 gamma-ray photons per pulse at 0.776-MeV using a specially designed laser system in
concert with a 120-MeV electron beam. The laser system uses a common all-fiber femtosecond front-end to drive a
dual-arm and dual-wavelength 10-Hz amplifier chain. First, a photo-gun drive laser, producing 250-fs ~mJ pulses at
1053-nm which are up-shifted and pulse stacked to produce a 10-ps temporal top-hat pulse at the fourth harmonic.
This pulse illuminates a novel high-gradient (120-MeV/m) photogun utilizing a sputtered magnesium photocathode.
With a QE in excess of 10-4, over a
Photo gun snanoCoulomb of charge is produced with
only 10-uJ of illumination with our 263-nm
spatially and temporally flat-top pulse.
After a five-section linear accelerator, 120-
MeV nC electron bunches are produced,
importantly preserving the 2.5 mm-mrad
emittance measured at injection.
, 4 , , The second arm of the laser system
J 12p~e Ultra-sable fber laser
Tsly programmable UV, produces an interaction drive laser pulse
Test staton 1O-ps FTL drive laser which produces 10-ps 1-J pulses at 1064-
nm through chirped pulse amplification in
flashlamp-pumped Nd:YAG. High-
Robust, commercial dispersion chirped fiber bragg gratings are
compressorlaser amplifier used at both wavelengths to produce 2-ns
and 6-ns, respectively, stretched pulses. As
the spectral bandwidth of the 10-ps
interaction pulses is lOx or more narrower
than previous chirped-pulse amplified laser
systems based on, for example, Ti: Sapphire or Nd:glass, we employ a novel hyper-dispersion pulse compressor to
provide the ~4x109 fs2 (7100 ps/nm) dispersion required to recompress the 1-J amplified pulses, which are
subsequent frequency tripled to provide 100-mJ, 10-ps, 355-nm interaction laser pulses at a common 35-um FWHM
focus with the 120-MeV electron beam.
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Albert, F.; Anderson, G.; Anderson, S.; Bayramian, A.; Berry, B.; Betts, S. et al. Ultrabright Laser-based MeV-class Light Source, article, April 2, 2008; Livermore, California. (https://digital.library.unt.edu/ark:/67531/metadc899447/m1/3/: accessed April 24, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.