System and method for high precision isotope ratio destructive analysis
AssigneeBattelle Memorial Institute
InventorsBruce A. Bushaw, Norman C. Anheier, Jon R. Phillips
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Abstract
A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).
Claims19
A method for high-precision isotope ratio measurement, the method comprising the steps of:
- generating a vapor plume containing at least two isotopes of the same or different atoms or molecular compounds, each isotope includes an isotope transition different and distinct from the other isotope;
- locking two wavelength-stabilized probe laser beams to respective wavelengths whereby each laser wavelength is separated a selected distance from the other wavelength with each laser wavelength fixed to a respective isotope transition line;
- forming a precisely collinear beam with the probe laser beams and directing same through the vapor plume such that the collinear beam traverses the same volume therein;
- measuring intensity of each laser beam at the selected wavelengths before and after generating the vapor plume;
- and
- determining the isotope ratio of the at least two isotopes based on the measured laser beam intensity at each wavelength.
A system for high-precision isotope ratio measurement, the system comprising:
- an ablation laser configured to deliver a laser beam that vaporizes a sample containing at least two isotopes of the same or different atoms or molecular compounds forming a vapor plume, each isotope includes an isotope transition different and distinct from the other isotope;
- two wavelength-stabilized probe laser beams locked (tuned) to respective wavelengths whereby each laser wavelength is separated a selected distance from the other wavelength with each laser wavelength fixed to a respective isotope transition line;
- an alignment device or process configured to optically combine and align the at least two probe laser beams to form a precisely collinear beam that directs same through the vapor plume such that the collinear beam traverses the same volume of the vapor plume;
- a separator configured to separate the different wavelengths of the precisely collinear beam after transmission through the vapor plume;
- and
- at least two optical detectors configured to measure intensity of each laser beam at the selected isotope absorbance wavelengths for determination of the isotope ratio of the at least two isotopes.
Dependencies are inferred from the claim text.