Methods for collection, dark correction, and reporting of spectra from array detector spectrometers

Abstract

Methods and systems for spectrometer dark correction are described which achieve more stable baselines, especially towards the edges where intensity correction magnifies any non-zero results of dark subtraction, and changes in dark current due to changes in temperature of the camera window frame are typically more pronounced. The resulting induced curvature of the baseline makes quantitation difficult in these regions. Use of the invention may provide metrics for the identification of system failure states such as loss of camera vacuum seal, drift in the temperature stabilization, and light leaks. In system aspects of the invention, a processor receives signals from a light detector in the spectrometer and executes software programs to calculate spectral responses, sum or average results, and perform other operations necessary to carry out the disclosed methods. In most preferred embodiments, the light signals received from a sample are used for Raman analysis.

Description

FIELD OF THE INVENTION[0001]This invention relates generally to spectrometers and, in particular, to methods for collection, dark correction and reporting from such instruments.BACKGROUND OF THE INVENTION[0002]Electronic light-recording devices such as charge-coupled display (CCD) cameras, single element arrays, as found in InGaAs cameras, and so forth, have a dark response (i.e., a signal in the absence of light) which must be corrected. Normally this involves taking an exposure cycle in the absence of light from the sample to be measured and storing it as a “dark spectrum.” Light from the sample is then passed to the camera for an identical exposure cycle to generate an “uncorrected sample spectrum.” A “corrected” sample spectrum is then computed by subtracting the dark spectrum from the uncorrected sample spectrum. (Other forms of correction are then computed to correct for the spectral responsivity of the detectors, the spectral mapping of the array, interpolation, etc., but the...

AI Technical Summary

Benefits of technology

This invention is about a system and process for correcting dark current in a spectrometer. The goal is to get efficient dark correction while keeping the total data collection cycle to a minimum. The invention also enables quicker reporting of data than that which would normally be dictated by accurately quantiting the weakest signal of interest. The invention improves matching of dark subtraction to the true dark, resulting in more stable baselines and reducing non-zero results of dark subtraction. Additionally, the invention provides metrics for identifying system failure states such as loss of camera vacuum seal, drift in temperature stabilization, and light leaks.

Problems solved by technology

The resulting induced curvature of the baseline makes quantitation difficult in these regions.

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