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Title: A broadband gamma-ray spectrometry using novel unfolding algorithms for characterization of laser wakefield-generated betatron radiation

We present a high-flux, broadband gamma-ray spectrometry capable of characterizing the betatron radiation spectrum over the photon energy range from 10 keV to 20 MeV with respect to the peak photon energy, spectral bandwidth, and unique discrimination from background radiations, using a differential filtering spectrometer and the unfolding procedure based on the Monte Carlo code GEANT4. These properties are experimentally verified by measuring betatron radiation from a cm-scale laser wakefield accelerator (LWFA) driven by a 1-PW laser, using a differential filtering spectrometer consisting of a 15-filter and image plate stack. The gamma-ray spectra were derived by unfolding the photostimulated luminescence (PSL) values recorded on the image plates, using the spectrometer response matrix modeled with the Monte Carlo code GEANT4. The accuracy of unfolded betatron radiation spectra was assessed by unfolding the test PSL data simulated with GEANT4, showing an ambiguity of less than 20% and clear discrimination from the background radiation with less than 10%. The spectral analysis of betatron radiation from laser wakefield-accelerated electron beams with energies up to 3 GeV revealed radiation spectra characterized by synchrotron radiation with the critical photon energy up to 7 MeV. The gamma-ray spectrometer and unfolding method presented here facilitate an in-depth understandingmore » of betatron radiation from LWFA process and a novel radiation source of high-quality photon beams in the MeV regime.« less
Authors:
; ; ; ; ;  [1] ; ; ; ;  [1] ;  [2] ;  [3] ; ;  [4] ; ; ;  [1] ;  [2]
  1. Center for Relativistic Laser Science, Institute for Basic Science (IBS), Gwangju 500-712 (Korea, Republic of)
  2. (Korea, Republic of)
  3. Nuclear Data Center, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of)
  4. Advanced Photonics Research Institute, GIST, Gwangju 500-712 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22482636
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 86; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; BACKGROUND RADIATION; BETATRONS; ELECTRON BEAMS; GAMMA SPECTRA; GAMMA SPECTROMETERS; GAMMA SPECTROSCOPY; GEV RANGE 01-10; KEV RANGE; LASERS; MEV RANGE 10-100; MONTE CARLO METHOD; PHOTOLUMINESCENCE; PHOTONS; SYNCHROTRON RADIATION; WAKEFIELD ACCELERATORS