Optimized x-ray emission from 10 ns long germanium x-ray sources at the National Ignition Facility

K Werellapatha; G N Hall; C Krauland; A Krygier; N Bhandarkar; D K Bradley; F Coppari; M G Gorman; C Heinbockel; G E Kemp; S F Khan; A Lazicki; N Masters; M J May; S R Nagel; N E Palmer; J H Eggert; L R Benedetti

doi:10.1063/5.0106696

Optimized x-ray emission from 10 ns long germanium x-ray sources at the National Ignition Facility

Rev Sci Instrum. 2022 Dec 1;93(12):123902. doi: 10.1063/5.0106696.

Authors

K Werellapatha¹, G N Hall¹, C Krauland², A Krygier¹, N Bhandarkar¹, D K Bradley¹, F Coppari¹, M G Gorman¹, C Heinbockel¹, G E Kemp¹, S F Khan¹, A Lazicki¹, N Masters¹, M J May¹, S R Nagel¹, N E Palmer¹, J H Eggert¹, L R Benedetti¹

Affiliations

¹ Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
² General Atomics, San Diego, California 92121, USA.

PMID: 36586918
DOI: 10.1063/5.0106696

Abstract

This study investigates methods to optimize quasi-monochromatic, ∼10 ns long x-ray sources (XRS) for time-resolved x-ray diffraction measurements of phase transitions during dynamic laser compression measurements at the National Ignition Facility (NIF). To support this, we produce continuous and pulsed XRS by irradiating a Ge foil with NIF lasers to achieve an intensity of 2 × 10¹⁵ W/cm², optimizing the laser-to-x-ray conversion efficiency. Our x-ray source is dominated by Ge He-α line emission. We discuss methods to optimize the source to maintain a uniform XRS for ∼10 ns, mitigating cold plasma and higher energy x-ray emission lines.