Note: Radiochemical measurement of fuel and ablator areal densities in cryogenic implosions at the National Ignition Facility

C Hagmann; D A Shaughnessy; K J Moody; P M Grant; N Gharibyan; J M Gostic; P T Wooddy; P C Torretto; B B Bandong; R Bionta; C J Cerjan; L A Bernstein; J A Caggiano; H W Herrmann; J P Knauer; D B Sayre; D H Schneider; E A Henry; R J Fortner

doi:10.1063/1.4926743

Note: Radiochemical measurement of fuel and ablator areal densities in cryogenic implosions at the National Ignition Facility

Rev Sci Instrum. 2015 Jul;86(7):076105. doi: 10.1063/1.4926743.

Authors

C Hagmann¹, D A Shaughnessy¹, K J Moody¹, P M Grant¹, N Gharibyan¹, J M Gostic¹, P T Wooddy¹, P C Torretto¹, B B Bandong¹, R Bionta¹, C J Cerjan¹, L A Bernstein¹, J A Caggiano¹, H W Herrmann², J P Knauer³, D B Sayre¹, D H Schneider¹, E A Henry¹, R J Fortner¹

Affiliations

¹ Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94551, USA.
² Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
³ Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA.

PMID: 26233419
DOI: 10.1063/1.4926743

Abstract

A new radiochemical method for determining deuterium-tritium (DT) fuel and plastic ablator (CH) areal densities (ρR) in high-convergence, cryogenic inertial confinement fusion implosions at the National Ignition Facility is described. It is based on measuring the (198)Au/(196)Au activation ratio using the collected post-shot debris of the Au hohlraum. The Au ratio combined with the independently measured neutron down scatter ratio uniquely determines the areal densities ρR(DT) and ρR(CH) during burn in the context of a simple 1-dimensional capsule model. The results show larger than expected ρR(CH) values, hinting at the presence of cold fuel-ablator mix.