Free-moving Quantitative Gamma-ray Imaging

TL;DR

This paper advances gamma-ray imaging by enabling accurate 3D source mapping with free-moving detectors, using Monte Carlo simulations and experimental validation to achieve absolute intensity quantification in complex environments.

Contribution

It introduces a method for characterizing detector response and performing quantitative 3D gamma-ray mapping with free-moving systems, improving upon previous relative intensity techniques.

Findings

Successful experimental 3D mapping in complex environments

Quantitative source activity estimation achieved

Validated Monte Carlo simulations for detector response

Abstract

The ability to map and estimate the activity of radiological source distributions in unknown three-dimensional environments has applications in the prevention and response to radiological accidents or threats as well as the enforcement and verification of international nuclear non-proliferation agreements. Such a capability requires well-characterized detector response functions, accurate time-dependent detector position and orientation data, a digitized representation of the surrounding 3D environment, and appropriate image reconstruction and uncertainty quantification methods. We have previously demonstrated 3D mapping of gamma-ray emitters with free-moving detector systems on a relative intensity scale using a technique called Scene Data Fusion (SDF). Here we characterize the detector response of a multi-element gamma-ray imaging system using experimentally benchmarked Monte Carlo simulations and perform 3D mapping on an absolute intensity scale. We present experimental reconstruction results from hand-carried and airborne measurements with point-like and distributed sources in known configurations, demonstrating quantitative SDF in complex 3D environments.