Non-destructive structural imaging of steelwork with atomic magnetometers

TL;DR

This paper presents a non-destructive method for imaging steel structures using atomic magnetometers, capable of detecting profile thinning and structural features at room temperature without environmental shielding.

Contribution

It introduces a novel application of Cs radio-frequency atomic magnetometers for non-invasive steelwork imaging in real-world, unscreened environments, including detection behind conductive barriers.

Findings

Sensitivity of 0.1 mm in profile detection

Successful imaging at room temperature without shielding

Effective background field compensation demonstrated

Abstract

We demonstrate the imaging of ferromagnetic carbon steel samples and we detect the thinning of their profile with a sensitivity of 0.1 mm using a Cs radio-frequency atomic magnetometer. Images are obtained at room temperature, in magnetically unscreened environments. By using a dedicated arrangement of the setup and active compensation of background fields, the magnetic disturbance created by the samples' magnetization is compensated. Proof-of-concept demonstrations of non-destructive structural evaluation in the presence of concealing conductive barriers are also provided. The relevant impact for steelwork inspection and health and usage monitoring without disruption of operation is envisaged, with direct benefit for industry, from welding in construction to pipeline inspection and corrosion under insulation in the energy sector.