Gm. Zeng et al., SOFT-X-RAY SPECTRA OF HIGHLY IONIZED ELEMENTS WITH ATOMIC NUMBERS RANGING FROM 57 TO 82 PRODUCED BY COMPACT LASERS, Journal of applied physics, 75(4), 1994, pp. 1923-1930
X-ray emission spectra in the spectral range of 2-13 nm from 19 kinds
of material with high atomic numbers (lanthanum through lead) were rec
orded with a grazing incidence spectrometer equipped with a microchann
el plate detector. There is an intense, narrow spectral band in these
spectra which shifts toward shorter wavelength and becomes weak in int
ensity with increasing atomic number. The materials were irradiated ei
ther by a 4 J/35 ns slab Nd:glass laser or by a 0.5 J/8 ns Nd:YAG lase
r. The absolute photon intensities of the spectra were determined with
an absolutely calibrated charge coupled device camera. The peak spect
ral brightness of the emission at the peak intensity of the spectral b
and for lanthanum plasma was estimated to be 2.1 X 10(16) photons/s/mm
2/mrad2 in 0.1% bandwidth. The origin of the narrow, intense spectral
bands in the recorded spectra and their dependence on target materials
and laser wavelength are interpreted.