Charged-particle ρR measurements at the NIF

Alex Zylstra, Massachusetts Institute of Technology

The Wedge Range Filter (WRF) proton spectrometer diagnostic was developed for OMEGA and recently transferred to the National Ignition Facility as a National Ignition Campaign (NIC) diagnostic. In tuning campaign implosions containing D and 3He gas the WRFs measure the proton spectrum from the reaction D+3He → p (14.7 MeV) + 4He (3.6 MeV). The energy downshift of the 14.7 MeV proton is directly related to the total ρR. On recent tuning campaign implosions the WRFs have measured ρR at two distinct nuclear production times. On layered THD implosions the WRFs measure the recoil proton spectrum from np scattering in the THD fuel and CH ablator. The spectrum is dominated by signal from the ablator, and the spectral shape gives the ablator ρR. WRF spectrometers fielded simultaneously on the pole and equator also give a measurement of field (E or B) effects at the LEH and polar ρR asymmetries.

Abstract Author(s): A. B. Zylstra, F. Seguin, J. Frenje, H. Rinderknecht, M. Rosenberg, M. Gatu Johnson, D. Casey, C.K. Li, N. Sinenian, M. Manuel, C. Waugh, and R. Petrasso (MIT)R. Bionta, D. Callahan, G. Collins, M. Eckart, J. Edwards, S. Friedrich, S. Glenzer, S. Haan, S. Hatchett, D. Hicks, K. Knittel, O. Landen, D. Larson, R. London, A. Mackinnon, N. Meezan, R. Prasad, J.R. Rygg, S. Weber, R. Zacharias (LLNL)R. Betti, V. Glebov, P. McKenty, P. Radha, C. Sangster, C. Stoeckl (LLE)R. Leeper, R. Olson (SNL)J. Kline, G. Kyrala, D. Wilson (LANL)J. Kilkenny, A. Nikroo (GA)