Multiple Monoenergetic Gamma Radiography (MMGR) with a compact superconducting cyclotron

TL;DR

This paper demonstrates a novel gamma radiography technique using a superconducting cyclotron to generate monoenergetic photons via inelastic nuclear reactions, enabling accurate detection of high-Z materials like uranium and plutonium.

Contribution

It introduces a proof-of-concept method employing inelastic ($p,p'$) reactions with a superconducting cyclotron for improved material identification in security screening.

Findings

Successfully generated monoenergetic photons at multiple energies.

Accurately reconstructed areal densities and $Z_{eff}$ of test objects.

Potential for mobile, high-specificity cargo screening applications.

Abstract

Smuggling of special nuclear materials (SNM) and nuclear devices through borders and ports of entry constitutes a major risk to global security. Technologies are needed to reliably screen the flow of commerce for the presence of high-$Z$ materials such as uranium and plutonium. Here we present an experimental proof-of-concept of a technique which uses inelastic ($p,p'$) nuclear reactions to generate monoenergetic photons, which provide means to measure the areal density and the effective-$Z$ ($Z_{\text{eff}}$) of an object with an accuracy which surpasses that achieved by current methods. We use an ION-12$^{ \text{SC}}$ superconducting 12~MeV proton cyclotron to produce 4.4, 6.1, 6.9, and 7.1~MeV photons from a variety of nuclear reactions. Using these photons in a transmission mode we show that we are able to accurately reconstruct the areal densities and $Z_{\text{eff}}$ of a test object. This methodology could enable mobile applications to screen commercial cargoes with high material specificity, providing a means of distinguishing common cargo materials from high-Z materials that include uranium and plutonium.