Probing High Areal-Density Cryogenic Deuterium-Tritium Implosions Using Downscattered Neutron Spectra Measured By The Magnetic Recoil Spectrometer

For the first time high areal-density (rho R) cryogenic deuterium-tritium (DT) implosions have been probed using downscattered neutron spectra measured with the magnetic recoil spectrometer (MRS) [J. A. Frenje , Rev. Sci. Instrum. 79, 10E502 (2008)], recently installed and commissioned on OMEGA [T. R. Boehly , Opt. Commun. 133, 495 (1997)]. The rho R data obtained with the MRS have been essential for understanding how the fuel is assembled and for guiding the cryogenic program at the Laboratory for Laser Energetics (LLE) to rho R values up to similar to 300 mg/cm(2). The rho R data obtained from well-established charged particle spectrometry techniques [C. K. Li , Phys. Plasmas 8, 4902 (2001)] were used to authenticate the MRS data for low-rho R plastic capsule implosions, and the rho R values inferred from these techniques are in excellent agreement, indicating that the MRS technique provides high-fidelity data. Recent OMEGA-MRS data and Monte Carlo simulations have shown that the MRS on the NIF [G. H. Miller , Nucl. Fusion 44, S228 (2004)] will meet most of the absolute and relative requirements for determining rho R, ion temperature (T(i)) and neutron yield (Y(n)) in both low-yield, tritium-rich, deuterium-lean, hydrogen-doped implosions and high-yield DT implosions. (C) 2010 American Institute of Physics. [doi:10.1063/1.3304475]