title: Parallax diagnostics of radiation source geometric dilution for iron opacity experiments.
abstract: Experimental tests are in progress to evaluate the accuracy of the modeled iron opacity at solar interior conditions [J. E. Bailey et al., Phys. Plasmas 16, 058101 (2009)]. The iron sample is placed on top of the Sandia National Laboratories z-pinch dynamic hohlraum (ZPDH) radiation source. The samples are heated to 150-200 eV electron temperatures and 7× 10(21)-4× 10(22) cm(-3) electron densities by the ZPDH radiation and backlit at its stagnation [T. Nagayama et al., Phys. Plasmas 21, 056502 (2014)]. The backlighter attenuated by the heated sample plasma is measured by four spectrometers along ±9° with respect to the z-pinch axis to infer the sample iron opacity. Here, we describe measurements of the source-to-sample distance that exploit the parallax of spectrometers that view the half-moon-shaped sample from ±9°. The measured sample temperature decreases with increased source-to-sample distance. This distance must be taken into account for understanding the sample heating.
authors.affiliation: Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
authors.forename: T
authors.initials: T
authors.lastname: Nagayama
authors.affiliation: Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Bailey
authors.affiliation: Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
authors.forename: G
authors.initials: G
authors.lastname: Loisel
authors.affiliation: Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
authors.forename: G A
authors.initials: GA
authors.lastname: Rochau
authors.affiliation: Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Falcon