PSFC/JA-09-03 Diagnosing fuel ρR and ρR asymmetries in cryogenic DT implosions using charged-particle spectrometry at OMEGA

Determining fuel areal density (ρR) in moderate-ρR (100-200 mg/cm 2) cryogenic DT implosions is challenging as it requires new spectrometry techniques and analysis methods to be developed. In this paper, we describe a new method for analyzing the spectrum of knock-on deuterons (KO-D), elastically scattered by primary DT neutrons, from which a fuel ρR can be inferred for values up to ~200 mg/cm 2. This new analysis method, which uses Monte-Carlo modeling of a cryogenic DT implosion, improves significantly the previous analysis method in two fundamental ways. First, it is not affected by significant spatial-yield variations, which degrade the diagnosis of the fuel ρR (spatial yield variations of about ±20% are typically observed), and secondly, it does not break down when the fuel ρR exceeds ~70 mg/cm 2 .