Journal: Scientific Reports

Article Title: Quantitative analysis of tritiated water using cavity ring-down spectroscopy

doi: 10.1038/s41598-026-46080-1

Figure Lengend Snippet: ( a ) Experimental schematic of the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${4.3}\,{\upmu }$$\end{document} m CRDS system for tritiated water measurement. ( b ) Photograph of the optical setup. ( c ) Representative ring-down transient under baseline (no absorption) conditions. The setup consists of a continuous-wave DFB-QCL light source, an optical isolation system, and a high-finesse cavity housed within a vacuum-compatible gas cell. Key components include an acousto-optic modulator (AOM) for rapid light switching, a mode-matching telescope, and high-reflectivity (R > 99.99%) mirrors mounted on an ultra-low-expansion (ULE) glass base. The gas handling system enables precise sample introduction via a septum and controlled evacuation. To ensure stable sample vaporization and minimize adsorption, the sample introduction section is heated to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${90}\,^{\circ }$$\end{document} C (363 K) and the gas cell is maintained at \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${50}\,^{\circ }$$\end{document} C (323 K). The entire optical layout is constructed on the 60 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document} 40 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {cm}^2$$\end{document} water-cooled breadboard and enclosed in a nitrogen-purged glovebox to suppress atmospheric \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {CO}_2$$\end{document} absorption. Ring-down signals are captured by a liquid-nitrogen-cooled InSb photodetector and processed through a high-resolution digitizer and an FPGA-based controller.

Article Snippet: The beam polarization was then adjusted using a half-wave plate before being directed into an acousto-optic modulator (AOM; Isomet, M1208-G80-4).

Techniques: Isolation, Adsorption, Construct