Charged-particle spectroscopy for diagnosing shock ρR and strength in NIF implosions

The compact Wedge Range Filter (WRF) proton spectrometer was developed for OMEGA and transferred to the National Ignition Facility (NIF) as a National Ignition Campaign diagnostic. The WRF measures the spectrum of protons from D-He-3 reactions in tuning-campaign implosions containing D and He-3 gas; in this work we report on the first proton spectroscopy measurement on the NIF using WRFs. The energy downshift of the 14.7-MeV proton is directly related to the total rho R through the plasma stopping power. Additionally, the shock proton yield is measured, which is a metric of the final merged shock strength. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729672]