Progress on next generation gamma-ray Cherenkov detectors for the National Ignition Facility

H W Herrmann; Y H Kim; A B Zylstra; H Geppert-Kleinrath; K D Meaney; C S Young; F E Lopez; V E Fatherley; B J Pederson; J A Oertel; J E Hernandez; J Carrera; H Khater; M S Rubery; C J Horsfield; S Gales; A Leatherland; T Hilsabeck; J D Kilkenny; R M Malone; S H Batha

doi:10.1063/1.5039378

Progress on next generation gamma-ray Cherenkov detectors for the National Ignition Facility

Rev Sci Instrum. 2018 Oct;89(10):10I148. doi: 10.1063/1.5039378.

Authors

H W Herrmann¹, Y H Kim¹, A B Zylstra¹, H Geppert-Kleinrath¹, K D Meaney¹, C S Young¹, F E Lopez¹, V E Fatherley¹, B J Pederson¹, J A Oertel¹, J E Hernandez², J Carrera², H Khater², M S Rubery³, C J Horsfield³, S Gales³, A Leatherland³, T Hilsabeck⁴, J D Kilkenny⁴, R M Malone⁵, S H Batha¹

Affiliations

¹ Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
² Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
³ Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, United Kingdom.
⁴ General Atomics, San Diego, California 92186, USA.
⁵ Mission Support and Test Services, LLC, Los Alamos, New Mexico 87544, USA.

PMID: 30399772
DOI: 10.1063/1.5039378

Abstract

Fusion reaction history and ablator areal density measurements for Inertial Confinement Fusion experiments at the National Ignition Facility are currently conducted using the Gamma Reaction History diagnostic (GRH_6m). Future Gas Cherenkov Detectors (GCDs) will ultimately provide ∼100x more sensitivity, reduce the effective temporal response from ∼100 to ∼10 ps, and lower the energy threshold from 2.9 to 1.8 MeV, relative to GRH_6m. The first phase toward next generation GCDs consisted of inserting the existing coaxial GCD-3 detector into a reentrant well which puts it within 4 m of the implosion. Reaction history and ablator gamma measurement results from this Phase I are discussed here. These results demonstrate viability for the follow-on Phases of (II) the use of a revolutionary new pulse-dilation photomultiplier tube to improve the effective measurement bandwidth by >10x relative to current PMT technology; and (III) the design of a NIF-specific "Super" GCD which will be informed by the assessment of the radiation background environment within the well described here.