A technique for extending by ∼10(3) the dynamic range of compact proton spectrometers for diagnosing ICF implosions on the National Ignition Facility and OMEGA.

Abstract

Wedge Range Filter (WRF) proton spectrometers are routinely used on OMEGA and the NIF for diagnosing ρR and ρR asymmetries in direct- and indirect-drive implosions of D(3)He-, D2-, and DT-gas-filled capsules. By measuring the optical opacity distribution in CR-39 due to proton tracks in high-yield applications, as opposed to counting individual tracks, WRF dynamic range can be extended by 10(2) for obtaining the spectral shape, and by 10(3) for mean energy (ρR) measurement, corresponding to proton fluences of 10(8) and 10(9) cm(-2), respectively. Using this new technique, ρR asymmetries can be measured during both shock and compression burn (proton yield ∼10(8) and ∼10(12), respectively) in 2-shock National Ignition Facility implosions with the standard WRF accuracy of ±∼10 mg/cm(2).