| Autor: |
King PM; NIF and Photon Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, USA., Lemos N; NIF and Photon Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, USA., Shaw JL; Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA., Milder AL; Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA., Marsh KA; Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA., Pak A; NIF and Photon Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, USA., Hegelich BM; Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA., Michel P; NIF and Photon Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, USA., Moody J; NIF and Photon Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, USA., Joshi C; Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA., Albert F; NIF and Photon Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, USA. |
| Abstrakt: |
A versatile set of methods for analyzing x-ray energy spectra and photon flux has been developed for laser plasma accelerator experiments driven by picosecond lasers. Forward fit provides extrapolated broad energy spectrum measurements, while Ross pair and differential average transmission analysis provide directly measured data points using a particular diagnostic. Combining these methods allows the measurement of x-ray energy spectra with improved confidence. We apply the methods to three diagnostics (filter wheel, stacked image plate spectrometer, and step wedge), each sensitive to a different region of x-ray energies (<40 keV, 35-100 keV, and 60-1000 keV, respectively), to characterize the analysis methods using laser-driven bremsstrahlung x-rays. We then apply the methods to measure three x-ray mechanisms, betatron, inverse Compton scattering, and bremsstrahlung, driven by a laser plasma accelerator. The analysis results in the measurement of x-ray energy spectra ranging from 10 keV to 1 MeV with peak flux greater than 10 10 photons/keV/Sr. The combined analysis methods provide a robust tool to accurately measure broadband x-ray sources (keV to MeV) driven by laser plasma acceleration with picosecond, kilojoule-class lasers. |
