Diagnosing fuel ρ R and ρ R asymmetries in cryogenic deuterium-tritium implosions using charged-particle spectrometry at OMEGA

Abstract

Determining fuel areal density (ρ R) in moderate- ρ R (100-200 mg/ cm2) cryogenic deuterium-tritium (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-Ds), elastically scattered by primary DT neutrons, from which a fuel ρ R can be inferred for values up to ∼200 mg/ cm2. 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 ρ R (spatial yield variations of about ±20% are typically observed), and second, it does not break down when the fuel ρ R exceeds ∼70 mg/ cm2. © 2009 American Institute of Physics.