Use of d-3He proton spectroscopy as a diagnostic of shell rho r in capsule implosion experiments with approximately 0.2 NIF scale high temperature Hohlraums at Omega.
We present the calculations and preliminary results from experiments on the Omega laser facility using d-(3)He filled plastic capsule implosions in gold Hohlraums. These experiments aim to develop a technique to measure shell rho r and capsule unablated mass with proton spectroscopy and will be applied to future National Ignition Facility (NIF) experiments with ignition scale capsules. The Omega Hohlraums are 1900 microm length x 1200 microm diameter and have a 70% laser entrance hole. This is approximately a 0.2 NIF scale ignition Hohlraum and reaches temperatures of 265-275 eV similar to those during the peak of the NIF drive. These capsules can be used as a diagnostic of shell rho r, since the d-(3)He gas fill produces 14.7 MeV protons in the implosion, which escape through the shell and produce a proton spectrum that depends on the integrated rho r of the remaining shell mass. The neutron yield, proton yield, and spectra change with capsule shell thickness as the unablated mass or remaining capsule rho r changes. Proton stopping models are used to infer shell unablated mass and shell rho r from the proton spectra measured with different filter thicknesses. The experiment is well modeled with respect to Hohlraum energetics, neutron yields, and x-ray imploded core image size, but there are discrepancies between the observed and simulated proton spectra.
Delamater
N D
ND
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Wilson
D C
DC
Kyrala
G A
GA
Seifter
A
A
Hoffman
N M
NM
Dodd
E
E
Singleton
R
R
Glebov
V
V
Stoeckl
C
C
Li
C K
CK
Petrasso
R
R
Frenje
J
J