One of our research goals at the Idaho Accelerator Center focuses on Laser-Compton Scattering (LCS) based nuclear science applications such as non-destructively quantifying concentrations of transuranic (TRIJ) elements in a surrogate of spent nuclear fuel and imaging. Non-destructive techniques include x-ray transmission and x-ray fluorescence. Both of these can be very sensitive techniques with tunable monochromatic x-rays. We investigated quasi-monochromatic x-rays from LCS for this purpose.

Four sharp ∼20 keV, ∼36.7 keV, ∼99 keV, and ∼122 keV LCS peaks were produced in four separate experiments using electron beams tuned to ∼33 MeV, -∼32 MeV, ∼37 MeV, and ∼41 MeV that were brought in collision with the Nd:YAG laser (the peak laser power was 4 GW) operating at 1064 nm, 532 nm and 266 nm wavelengths respectively. The linac was operating at 60 Hz with an electron beam pulse length of about 50 ps and a peak current of about 7 A.

X-ray fluorescence (XRF) experiments were first carried out to identify elemental XRF emission from Ag, Cd, and Sn foils with thicknesses ranging from 25–500 μm, following the absorption of ∼36.7 keV LCS x-rays. The intensities of the measured Kα₁ emission lines were then compared to the predicted Kα₁ intensities; based on the comparison, there was an estimated deviation of up to ≈10.4% between the predicted and measured Kα₁ intensities.

Next, the transmission experiments were carried out by transmitting a ∼99 keV LCS x-ray beam through Bi foils of thicknesses ranging from 50–250 μm to measure the transmission of the interrogating LCS x-ray beam. There was a relative deviation of up to ≈9.4 % between the predicted and measured transmission respectively.

We then focused on exploiting the Hybrid K-Edge Densitometry (HKED) technique for the purpose of quantifying the concentrations of Uranium in the surrogate of spent nuclear fuel using a ∼122 keV LCS x-ray beam. The measured concentrations deviated by about 2.87% and 11.86% between the HKED measurement procedure and the point source transmission measurement procedure respectively.

Finally, experiments were carried out to demonstrate phase-contrast imaging by transmitting ∼20 keV LCS x-ray beam through fish samples. The vital organs were distinguishable in the processed radiographic image.