A multi-channel x-ray temporal diagnostic for measurement of time-resolved electron temperature in cryogenic deuterium-tritium implosions at OMEGA

N Kabadi; A Sorce; C Stoeckl; H W Sio; P Adrian; M Bedzyk; J Frenje; J Katz; J Knauer; J Pearcy; D Weiner; B A Aguirre; R Betti; A Birkel; D Cao; M Gatu Johnson; D Patel; R D Petrasso; S P Regan

doi:10.1063/5.0042329

A multi-channel x-ray temporal diagnostic for measurement of time-resolved electron temperature in cryogenic deuterium-tritium implosions at OMEGA

Rev Sci Instrum. 2021 Feb 1;92(2):023507. doi: 10.1063/5.0042329.

Authors

N Kabadi¹, A Sorce², C Stoeckl², H W Sio³, P Adrian¹, M Bedzyk², J Frenje¹, J Katz², J Knauer², J Pearcy¹, D Weiner², B A Aguirre⁴, R Betti², A Birkel¹, D Cao², M Gatu Johnson¹, D Patel², R D Petrasso¹, S P Regan²

Affiliations

¹ Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA.
² University of Rochester Laboratory for Laser Energetics, Rochester, New York 14623, USA.
³ Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
⁴ Sandia National Laboratories, Albuquerque, New Mexico 87123, USA.

PMID: 33648078
DOI: 10.1063/5.0042329

Abstract

Electron-temperature (T_e) measurements in implosions provide valuable diagnostic information, as T_e is unaffected by residual flows and other non-thermal effects unlike ion temperature inferred from a fusion product spectrum. In OMEGA cryogenic implosions, measurement of T_e(t) can be used to investigate effects related to time-resolved hot-spot energy balance. The proposed diagnostic utilizes five fast-rise (∼15 ps) scintillator channels with distinct x-ray filtering. Titanium and stepped aluminum filtering were chosen to maximize detector sensitivity in the 10 keV-20 keV range, as it has been shown that these x rays have similar density and temperature weighting to the emitted deuterium-tritium fusion neutrons. Initial data collected using a prototype nosecone on the existing neutron temporal diagnostic demonstrate the validity of this diagnostic technique. The proposed system will be capable of measuring spatially integrated T_e(t) with 20 ps time resolution and <10% uncertainty at peak emission in cryogenic DT implosions.