D-He-3 proton spectra for diagnosing shell rho R and fuel T-i of imploded capsules at OMEGA

Recent work has resulted in the first high-resolution, spectroscopic measur ements of energetic charged particles on OMEGA laser facility [T. R. Boehly , Opt. Commun. 133, 496 (1997)]. Energy spectra of charged fusion products have been obtained from two spectrometers, and have been used to deduce va rious physical quantities in imploded capsules. In this paper the first use of 14.7 MeV deuterium-helium3 (D-He-3) proton spectra for diagnosing shell areal density (rho R) and fuel ion temperature (T-i) is discussed. For thi ck-plastic shell capsules, shell areal densities between 20 and 70 mg/cm(2) and ion temperatures between 3 and 5 keV have been determined. The spectra l linewidths associated with such capsules are found to be wider than the d oppler widths. This effect, the focus of future study, is the result of rho R evolution during the burn; or is the result of an extended burn region; or results from nonuniformities in the shell. For thin-glass shell capsules , the spectral linewidths are dominated by the doppler width, and ion tempe ratures between 10 and 15 keV were determined. These measurements have been also compared and contrasted with the results from neutron measurements an d from one-dimension hydrodynamic simulations. (C) 2000 American Institute of Physics. [S1070-664X(00)01306-9].