ABSTRACT
The volumetric heating of a thin copper target has been studied with time resolved x-ray spectroscopy. The copper target was heated by a plasma produced using the Lawrence Livermore National Laboratory's Compact Multipulse Terawatt (COMET) laser. A variable spaced grating spectrometer coupled to an x-ray streak camera measured soft x-ray emission (800-1550 eV) from the back of the copper target to characterize the bulk heating of the target. Radiation hydrodynamic simulations were modeled in two-dimensions using the HYDRA code. The target conditions calculated by HYDRA were post-processed with the atomic kinetics code CRETIN to generate synthetic emission spectra. A comparison between the experimental and simulated spectra indicates the presence of specific ionization states of copper and the corresponding electron temperatures and ion densities throughout the laser-heated copper target.
ABSTRACT
A large radius, R=44.3 m, high resolution grating spectrometer (HRGS) with 2400 lines/mm variable line spacing has been designed for laser-produced plasma experiments conducted at the Lawrence Livermore National Laboratory Jupiter Laser Facility. The instrument has been run with a low-noise, charge-coupled device detector to record high signal-to-noise spectra in the 10-50 A wavelength range. The instrument can be run with a 10-20 microm wide slit to achieve the best spectral resolving power, approaching 1000 and similar to crystal spectrometers at 12-20 A, or in slitless operation with a small symmetrical emission source. We describe preliminary spectra emitted from various H-like and He-like low Z ion plasmas heated by 100-500 ps (full width at half maximum), 527 nm wavelength laser pulses. This instrument can be developed as a useful spectroscopy platform relevant to laboratory-based astrophysics as well as high energy density plasma studies.
ABSTRACT
Determined the factor structure of the McCarthy Scales (1972) for a referred group of male and female children, ages 6 to 81/2, from rural eastern North Carolina and compared their factor structure to that of the standardization sample. Three hundred and one males and 177 females were separated into two groups and examined independently. The 21 individual test scores of the McCarthy were correlated and then subjected to a principal factor analysis followed by Varimax rotation. Three meaningful factors emerged for males and females: Verbal, Perceptual, and Motor factors for males and General-Cognitive, Verbal, and Memory factors for females. The factor analyses for males and females agreed with previous factor analytic studies conducted with referred samples on the absence of a Quantitative factor and inconsistencies in the emergence of General-Cognitive and Memory factors. Coefficients of congruence with Kaufman's (1975) standardization analysis suggest that the McCarthy Scales reflect a general dimension of cognitive ability rather than a measure of distinct abilities for a referred sample of males and females.
