In situ calibration of the Gamma Reaction History instrument using reference samples (“pucks”) for areal density measurements

¹ Los Alamos National Laboratory, PO Box 1663, Los Alamos, New Mexico 87545, USA
² Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR, UK
³ Lawrence Livermore National Laboratory, Livermore, California 94550, USA
⁴ National Security Technologies, LLC, Santa Barbara, California 93111, USA
⁵ Colorado School of Mines, Golden, Colorado 80401, USA
⁶ Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA

Published online: 15 November 2013

Abstract

The introduction of a sample of carbon, for example a disk or “puck”, near an imploding DT-filled capsule creates a source of ¹²C gamma rays that can serve as a reference for calibrating the response of the Gamma Reaction History (GRH) detector [1]. Such calibration is important in the measurement of ablator areal density ⟨ρR⟩_abl in plastic-ablator DT-filled capsules at OMEGA [2], by allowing ⟨ρR⟩_abl to be inferred as a function of ratios of signals rather than from absolute measurements of signal magnitudes. Systematic uncertainties in signal measurements and detector responses therefore cancel, permitting more accurate measurements of ⟨ρR⟩_abl.