Novel Application of Neutrinos to Evaluate U.S. Nuclear Weapons Performance

TL;DR

This paper explores using neutrino detection as a non-invasive method to evaluate nuclear weapon performance, proposing a scalable detector setup and analyzing the potential accuracy and challenges involved.

Contribution

It introduces a novel application of neutrino detection for nuclear weapon diagnostics and assesses the feasibility of a low-cost detector for real-world testing environments.

Findings

Neutrino detectors can measure nuclear yields with less than 4% statistical error.

Prompt neutrino rates differ significantly from steady-state assumptions.

A small-scale detector near a pulsed reactor can provide valuable data for nuclear diagnostics.

Abstract

There is a growing realization that neutrinos can be used as a diagnostic tool to better understand the inner workings of a nuclear weapon. Robust estimates demonstrate that an Inverse Beta Decay (IBD) neutrino scintillation detector built at the Nevada Test Site of 1000-ton active target mass at a standoff distance of 500 m would detect thousands of neutrino events per kTe of nuclear yield. This would provide less than 4% statistical error on measured neutrino rate and 5% error on neutrino energy. Extrapolating this to an error on the test device explosive yield requires knowledge from evaluated nuclear databases, non-equilibrium fission rates, and assumptions on internal neutron fluxes. Initial calculations demonstrate that prompt neutrino rates from a short pulse of Pu-239 fission is about a factor of two less than that from a steady state assumption. As well, there are significant energy spectral differences as a function of time after the pulse that needs to be considered. In the absence of nuclear weapons testing, many of the technical and theoretical challenges of a full nuclear test could be mitigated with a low cost smaller scale 20 ton fiducial mass IBD demonstration detector placed near a TRIGA pulsed reactor. The short duty cycle and repeatability of pulses would provide critical real environment testing and the measured neutrino rate as a function of time data would provide unique constraints on fission databases and equilibrium assumptions.