A magnetic recoil spectrometer (MRS) for $\rho $R, yield and T$_{i}$ measurements of implosions at OMEGA and the NIF

Charged-particle diagnostics have been extensively used for determining $\rho $R of several types of implosions, but they will fail for $\rho $R$>$200 mg/cm$^{2}$ and not work for the $\sim $300 mg/cm$^{2}$ expected in upcoming OMEGA cryogenic DT implosions or the 700-2000 mg/cm$^{2 }$expected in NIF implosions. We are therefore currently developing a neutron spectrometer for measurements of down-scattered neutrons from which $\rho $R in the 100 to 2000 mg/cm$^{2}$ can be inferred. The spectrometer is a Magnetic Recoil Spectrometer (MRS) that covers the energy range 6 to 32 MeV, which enables simultaneous measurements of down-scattered, primary and tertiary neutrons. Due to the MRS principle, measurements of these different neutrons are spatially separated, which is critical for successful $\rho $R measurements. This work was supported in part by UR-LLE, LLNL, the U.S. DoE, and the N.Y. State Energy Research and Development Authority$. $