High energy X-ray spectroscopy at high-energy laser facilities
by
Csilla Szabo, Naval Research Laboratory, Washington
→
Europe/Berlin
AER19, room 3.11
AER19, room 3.11
Description
With increasing laser irradiance at large laser facilities the need for the knowledge of the high-energy x-ray spectrum is more and more significant. X-ray continuum and characteristic x-ray lines can provide details about atomic physics processes in the plasma and a way to determine plasma parameters (electron density and temperature).
Cylindrically bent transmission crystal spectrometers in the Cauchois geometry have been proven to be a good tool to map the high-energy x-ray spectrum at high density experimental facilities. This wavelength dispersive method is capable of providing a high-resolution x-ray spectrum within the time frame (a few nanoseconds) of a single high energy density laser shot. Our team, a collaboration between the Naval Research Laboratory (NRL) and the National Institute of Standards and Technology (NIST) has developed and deployed various high energy x-ray spectrometers for large laser facilities in the US and France.
Considering the small source size of the laser-solid interactions at large laser facilities the resolving power of these spectrometers can be even further enhanced by putting the detector beyond the focusing Rowland circle. This modification of the traditional spectrometer geometry also provides the ability for source size measurement based on the precise measurement of K x-ray peaks in the spectrum. This monochromatic x-ray source size measurement can provide information about the spread of the high-energy electrons in a solid target during a laser-solid interaction.
Basic design characteristics of the spectrometers will be described including new approaches adopting the general design for lower x-ray energies (down to 8 keV) and to gamma spectroscopy (up to 511 keV photon energies). A collection of experimental results will be provided from large laser facilities: OMEGA-EP at LLE, NY, USA, Titan laser facility at LLNL, CA, USA and the PICO2000 and the 100 TW facilities at LULI, France.
