Diamond atr artefact correction

A spectrometer arranged for performing Attenuated Total Reflectance (ATR) measurements comprising:

• a source of radiation;
• a detector for detecting radiation having passed through a diamond ATR crystal positioned in the spectrometer;
• and
• a processing unit for processing the output of the detector to produce sets of ATR spectral data;
• wherein the spectrometer has a memory for storing a pressure dependent diamond artefact reference spectrum and is arranged to acquire an initial set of ATR spectral data for a sample pressed into contact with a diamond ATR crystal;
• and the processing unit is arranged to:
• numerically match the pressure dependent diamond artefact reference spectrum to a corresponding pressure dependent diamond artefact in the initial set of ATR spectral data;
• and
• numerically subtract out the numerically matched pressure dependent diamond artefact reference spectrum from the initial set of ATR spectral data to yield a corrected set of ATR spectral data for the sample for output by the spectrometer.

A method of producing corrected diamond Attenuated Total Reflectance (ATR) spectral data comprising the steps of:

• obtaining a pressure dependent diamond artefact reference spectrum on a, first, reference spectrometer;
• acquiring, using a second spectrometer, an initial set of ATR spectral data for a sample pressed into contact with a diamond ATR crystal;
• numerically matching, using the second spectrometer, the pressure dependent diamond artefact reference spectrum to a corresponding pressure dependent diamond artefact in the initial set of ATR spectral data;
• and
• numerically subtracting out the numerically matched pressure dependent diamond artefact reference spectrum from the initial set of ATR spectral data to yield a corrected set of ATR spectral data for the sample for output by the second spectrometer.

A method of obtaining a pressure dependent diamond artefact reference spectrum for use in producing corrected diamond Attenuated Total Reflectance (ATR) spectral data, the method comprising the steps of:

• providing a diamond ATR crystal in a reference spectrometer and pressing a reference sample against the ATR crystal;
• varying the applied pressure with which the reference sample is pressed against the ATR crystal;
• obtaining, using the reference spectrometer, spectra for the reference sample at a plurality of applied pressures;
• determining pressure dependent features in the resulting spectra;
• determining at least one region in the spectrum exhibiting pressure dependence;
• generating a pressure dependent diamond artefact reference spectrum by restricting the range of the spectrum to said at least one region and including only features determined as pressure dependent in the respective determining step.

A method of correcting diamond Attenuated Total Reflectance (ATR) spectral data comprising the steps of:

• receiving an initial set of ATR spectral data for a sample pressed into contact with a diamond ATR crystal;
• numerically matching a pressure dependent diamond artefact reference spectrum to a corresponding pressure dependent diamond artefact in the initial set of ATR spectral data;
• and
• numerically subtracting out the numerically matched pressure dependent diamond artefact reference spectrum from the initial set of ATR spectral data to yield a corrected set of ATR spectral data for the sample.

A computer for correcting diamond Attenuated Total Reflectance (ATR) spectral data arranged under the control of software to:

• receive an initial set of ATR spectral data for a sample pressed into contact with a diamond ATR crystal;
• numerically match a pressure dependent diamond artefact reference spectrum to a corresponding pressure dependent diamond artefact in the initial set of ATR spectral data;
• and
• numerically subtract out the numerically matched pressure dependent diamond artefact reference spectrum from the initial set of ATR spectral data to yield a corrected set of ATR spectral data for the sample.