Laser Wakefield Acceleration of High-Quality Electron Beams to 300 MeV and Efficient Initiation of Photonuclear Reactions

Conference · Wed Nov 01 04:00:00 EST 2006 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2409214· OSTI ID:931070

Reed, S. A. ^[1]; Naumova, N. ^[1]; Vane, C Randy ^[2]; Beene, James R. ^[2]; Bulanov, S. S. ^[1]; Chvykov, V. ^[1]; Hou, B. ^[1]; Kalintchenko, G. ^[1]; Matsuoka, T. ^[1]; Rousseau, P. ^[1]; Schultz, David Robert ^[2]; Stracener, Dan ^[2]; Yanovsky, V. ^[1]; Maksimchuk, A. ^[1]

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1. University of Michigan
2. ORNL

By focusing 40-TW, 30-fs laser pulses to the intensity of 1019 W/cm² onto a supersonic He gas jet, we generated quasi-monoenergetic electron beams for plasma density in the narrow range of 1.5<= ne <=3 × 10¹⁹ cm³. We show that the energy, charge, divergence and pointing stability of the beam vary sensitively with ne within this range. The observed variations can be explained physically by the interplay among pump depletion and dephasing between accelerated electrons and plasma wave. An optimized quasi-monoenergetic beam of over 300 MeV and 10 mrad angular divergence is demonstrated at a plasma density of ne~1.5 × 10¹⁹ cm³. The quasi-monoenergeic electron beams with energy of 100-150 MeV and charge of 0.5 nC have been used to perform gamma-nuclear photofission of natural uranium targets. Through bremsstrahlung emission, such electron beams are well suited for the efficient generation of high energy (tens of MeV) gamma-rays necessary to induce photofission reactions. Quantitative gamma-ray spectroscopy of the irradiated U sample shows that more than ~10⁵ photonuclear reactions have been produced per Joule of laser energy, which is 10 to 50 times higher than in a previously reported experiments

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 931070
• Conference Information: Journal Name: AIP Conference Proceedings Journal Volume: 877
• Country of Publication: United States
• Language: English