Diffuse Reflectance Spectroscopy and Principal Component Analysis to Retrospectively Determine Production History of...

Area of Science:

• Materials Science
• Spectroscopy
• Nuclear Chemistry

Background:

• Plutonium compounds are critical in nuclear applications.
• Understanding their production history is vital for nuclear forensics and nonproliferation.
• Spectroscopic methods offer potential for retrospective analysis.

Purpose of the Study:

• To identify spectroscopic fingerprints of plutonium(IV) oxide (PuO2) and its precursor.
• To correlate spectral features with calcination temperatures used in PuO2 production.
• To develop a method for retrospective analysis of PuO2 process history.

Main Methods:

• Diffuse reflectance spectroscopy in the shortwave infrared (930-1600 nm).
• Analysis of eight PuO2 samples produced at varying calcination temperatures (300-900 °C).
• Principal Component Analysis (PCA) of spectral data.
• Ancillary Raman spectroscopy for corroboration.

Main Results:

• Plutonium(IV) oxide (PuO2) exhibits sharper spectral features at higher calcination temperatures.
• An electronic band at 1433 nm in PuO2 spectra indicates crystallinity, confirmed by Raman spectroscopy.
• Principal Component Analysis effectively categorized PuO2 samples based on calcination temperature.

Conclusions:

• Diffuse reflectance spectroscopy combined with PCA provides a method to determine PuO2 production history.
• This technique offers valuable retrospective information for nuclear forensics and nonproliferation.
• The 1433 nm band serves as a sensitive indicator of PuO2 crystallinity.