Sample cell monitoring system
AssigneeWyatt Technology Corporation
InventorsSteven D. Philips, Jeffrey M. Reece, Philip J. Wyatt
Life of this patent
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Abstract
The light intensity incident on a scattering sample contained in a scattering cell is monitored by simultaneous measurements of the light incident on the cell before entering it and the light transmitted through the cell after leaving it. Means to monitor the product of these signals is disclosed and how this product is related to the actual incident intensity at the sample is explained. The invention is presented in the context of the scattering cell of the parent application.
Claims12
A method for normalizing the scattered intensities of light from particles suspended in a solvent and illuminated by a collimated light beam comprising the steps of
- A. Measuring the intensity of light transmitted undeviated through the sample and external to the sample containing cell, I.sub.s ;
- B. Measuring a fraction of the incident light source intensity before entering the cell, I.sub.f ;
- C. Dividing all measured scattering intensities at specified scattering angles by the quantity .sqroot.I.sub.f I.sub.s, where I.sub.s is the intensity value measured in step A and I.sub.f is the intensity value measured in step B.
A sample cell monitor for generating a normalization factor by which means scattering light intensity values measured at a plurality of angles may be normalized by dividing each measured intensity by said normalizing factor, said sample cell containing a suspension of particles in a solvent solution that is illuminated by a collimated light beam that passes undeviated through the sample cell by entrance and exit window means provided therefore, and comprised of
- A. Detector means for measuring a value proportional to the incident light beam intensity before said beam enters said sample cell;
- B. Detector means for measuring a value proportional to the intensity of the light beam passing undeviated through the sample cell;
- C. Multiplication means forming a value proportional to the product of the value from said incident light beam detector means and said undeviated light beam detector means;
- D. Normalization generation means that forms normalization factor proportional to the square root of the product value of step C;
- E. Division means to divide said scattered light intensity values by said normalization factor.
Dependencies are inferred from the claim text.