Patent ID: 6888127

Claim:
A tool for determining the amount of a carbon isotope in a fluid, comprising: a laser source emitting at least one laser beam; a first volume of the fluid positioned so that at least a first portion of a laser beam passes through the fluid; a first downstream optical detector positioned to detect said first beam portion after said first beam portion passes through said first volume, said first optical detector emitting a first downstream signal corresponding to the strength of said first beam portion after passing through the first volume; a reference cell containing a concentration of the isotope and positioned so that at least a second portion of a laser beam passes through said concentration; a second downstream optical detector positioned to detect said second beam portion after said second beam portion passes through said reference cell, said second optical detector emitting a second downstream signal corresponding to the strength of said second beam portion after passing through said reference cell; a pre-dilution cell containing a portion of the fluid positioned so that at least a third portion of a laser beam passes through the portion of the fluid; a third downstream optical detector positioned to detect said third beam portion after said third beam portion passes through said pre-dilution cell, said third downstream optical detector emitting a third downstream signal corresponding to the strength of said third beam portion after passing through the pre-dilution cell; and a microprocessor receiving said first, second, and third downstream signals and calculating from the first and second downstream signals a parameter indicative of the presence of the isotope in the fluid, and wherein the microprocessor determines from the third downstream signal whether and to what degree to dilute the fluid with a diluent.