US 6,783,705 B1Granted

Calibration medium for wavelength calibration of U.V. absorbance detectors and methods for calibration

AssigneeWaters Investments Limited

InventorMichael J. Leveille

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Abstract

The invention features an optical medium for calibrating UV absorbance detectors, methods for making such an optical medium, and methods for calibrating UV absorbance detectors using such a medium. The optical calibration medium includes a gel-sol silica glass monolith with a rare-earth dopant therein. The rare-earth dopant exhibits at least one spectral feature in at least the far UV range. The constituents of the gel-sol silica glass monolith are selected so the rare-earth doped sol-gel glass monolith exhibits a transmittance in the far UV range so each distinct spectral feature of the rare-earth dopant in the far UV range is discernable. The transmittance in a particular embodiment is at least about 50% at about 250 nm. The rare earth materials selected for use as dopants are those exhibiting a wide range of spectral features, preferably over a range from about 190 nm to about 700 nm and more particularly exhibit at least one distinct spectral feature in the range from about 190 nm to about 300 nm. In a specific embodiment, the rare-earth dopant includes atoms of erbium, having spectral features in a range from about 190 nm to about 650 nm and a distinguishable far UV spectral feature at about 257 nm.

Claims9

Dependent claims

A method for calibrating an optical instrument which optical instrument has a spectral light source, said light source capable of emitting light in the far UV range which light travels along a light path and which light comprises at least one wavelength, means for receiving a sample said within said light path, and a sensor assembly for receiving light and producing a signal, said sensor assembly producing a signal upon receiving light having said wavelength, the calibration method comprising the steps of:

disposing a calibration medium so as to be in said light path between the light source and the sensor assembly said light source emitting light in the UV spectral range, said calibration medium including a sol-gel glass monolith for receiving and transmitting light along a said light path, said sol-gel glass monolith having constituents comprising a rare-earth dopant therein;
said constituents of the sol-gel glass monolith selected so the rare-earth doped sol-gel glass monolith exhibits a transmittance in the far UV range so at least one spectral feature of the rare-earth dopant in the far UV range is discernable and corresponds to a wavelength comprising a control value to allow the signal of said sensor assemble receiving light having said wavelength corresponding to said control value to be compared to a standard for determining the calibration of said optical instrument;
sensing the light passing through the calibration medium with said sensor assemble to produce signal;
and,
comparing the signal to at least one other signal to determine the calibration of said optical instrument.

2 more elements

An optical instrument comprising:

a spectral light source, said light source capable of emitting light in the far UV range which light travels along a light path and which light comprises at least one wavelength;
means for receiving a sample within said light path;
a sensor assembly for receiving light and producing a signal, said sensor assembly producing a signal upon receiving light having said wavelength;
a calibration medium capable of assuming a position in said light path between the light source and the sensor assembly, said calibration medium including a so-gel glass monolith for receiving and transmitting light, said sol-gel glass monolith having constituents comprising a rare-earth dopant therein;
said constituents of the sol-gel glass monolith selected so the rare-earth doped sol-gel glass monolith exhibits a transmittance in the far UV range so at least one spectral feature of the rare-earth dopant in the far UV range is discernable and corresponds to a control value to allow the signal of said sensor assembly receiving light having said wavelength corresponding to said control value to be compared to a standard for determining the calibration of said optical instrument.

2 more elements

Dependencies are inferred from the claim text.