title: 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.
abstract: 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.
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: N D
authors.initials: ND
authors.lastname: Delamater
authors.forename: D C
authors.initials: DC
authors.lastname: Wilson
authors.forename: G A
authors.initials: GA
authors.lastname: Kyrala
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authors.initials: A
authors.lastname: Seifter
authors.forename: N M
authors.initials: NM
authors.lastname: Hoffman
authors.forename: E
authors.initials: E
authors.lastname: Dodd
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authors.lastname: Singleton
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authors.lastname: Glebov
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authors.lastname: Stoeckl
authors.forename: C K
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authors.lastname: Li
authors.forename: R
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authors.lastname: Petrasso
authors.forename: J
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authors.lastname: Frenje