Improving a high-efficiency, gated spectrometer for x-ray Thomson scattering experiments at the National Ignition Facility

T Döppner; D Kraus; P Neumayer; B Bachmann; J Emig; R W Falcone; L B Fletcher; M Hardy; D H Kalantar; A L Kritcher; O L Landen; T Ma; A M Saunders; R D Wood

doi:10.1063/1.4959874

Improving a high-efficiency, gated spectrometer for x-ray Thomson scattering experiments at the National Ignition Facility

Rev Sci Instrum. 2016 Nov;87(11):11E515. doi: 10.1063/1.4959874.

Authors

T Döppner¹, D Kraus², P Neumayer³, B Bachmann¹, J Emig¹, R W Falcone², L B Fletcher⁴, M Hardy¹, D H Kalantar¹, A L Kritcher¹, O L Landen¹, T Ma¹, A M Saunders², R D Wood¹

Affiliations

¹ Lawrence Livermore National Laboratory, Livermore, California 94720, USA.
² University of California, Berkeley, California 94720, USA.
³ Gesellschaft für Schwerionenphysik, Darmstadt, Germany.
⁴ SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA.

PMID: 27910303
DOI: 10.1063/1.4959874

Abstract

We are developing x-ray Thomson scattering for applications in implosion experiments at the National Ignition Facility. In particular we have designed and fielded MACS, a high-efficiency, gated x-ray spectrometer at 7.5-10 keV [T. Döppner et al., Rev. Sci. Instrum. 85, 11D617 (2014)]. Here we report on two new Bragg crystals based on Highly Oriented Pyrolytic Graphite (HOPG), a flat crystal and a dual-section cylindrically curved crystal. We have performed in situ calibration measurements using a brass foil target, and we used the flat HOPG crystal to measure Mo K-shell emission at 18 keV in 2nd order diffraction. Such high photon energy line emission will be required to penetrate and probe ultra-high-density plasmas or plasmas of mid-Z elements.