K-shell spectra from hot dense aluminum layers buried in carbon and heated by ultrashort laser pulses

• Published in: Journal of quantitative spectroscopy & radiative transfer Vol. 81; no. 1; pp. 133 - 146
• Main Authors: Eidmann, K., Andiel, U., Pisani, F., Hakel, P., Mancini, R.C., Junkel-Vives, G.C., Abdallah, J., Witte, K.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2003
• Subjects: K-shell spectroscopy; Short pulse laser; Spectral line shifts; Short pulse laser; Spectral line shifts; K-shell spectroscopy
• ISSN: 0022-4073; 1879-1352
• DOI: 10.1016/S0022-4073(03)00067-0

Ultrashort laser pulses allow for the generation of hot plasmas near solid state densities. For this purpose a Ti:Sapphire laser was used, which delivers after frequency doubling, pulses of high contrast with an energy of about 60 mJ and a duration of 150 fs at 395 nm . The typical intensity on the target was a few 10 17 W/cm 2 . To achieve a high degree of uniformity we used targets consisting of a 25 nm thin Al tracer layer buried at different depths up to 400 nm in solid carbon. Time-integrated Al K-shell spectra are presented. Characteristic features of the spectra are significant high-order satellite line emission, strong line broadening and a center-of-mass line shift to the red, which was observed in transitions from principal quantum number n=2 or 3 to 1. Accurate measurement of the shift was made possible by using the cold Si K α line as an absolute wavelength calibration. In addition to time-integrated measurements, we used an ultrafast X-ray streak camera to obtain time and spectrally resolved spectra. Typical durations of the Ly α and He α lines are in the range 2–4 ps. The experimental results are compared with a time-dependent model, which combines hydrodynamic simulations, time-dependent atomic kinetics, detailed spectral line shapes including line shifts, and radiation transport.