Patent ID: 8159672

Claim:
A method of investigating a sample comprising the steps of: a) providing a system for monitoring samples comprising: a source of spectroscopic electromagnetic radiation; a means for supporting a sample; a reflecting means; a detector of spectroscopic electromagnetic radiation; and an intensity controlling filter means; said source and detector being mounted to a common support and laterally offset from one another, such that in use an incident beam of electromagnetic radiation from said source thereof is caused to approach a sample placed on said means for supporting a sample at an intended angle of incidence along a first locus, reflect from said sample interact with said reflecting means and proceed along a selection from the group consisting of: again interact with said sample and re-reflect therefrom at the intended angle of incidence, then proceed along a second locus and enter said detector; and proceed along a second locus and enter said detector; said beam also being caused to to pass through said intensity controlling means; said system further comprising means for controlling the distance between said source and detector which are mounted to a common support, and said means for supporting a sample; b) causing said distance between said common support and said means for supporting a sample to be increased and positioning a standard sample on said means for supporting a sample, then causing said distance between said common support and said means for supporting a sample to be decreased; c) causing an incident beam of electromagnetic radiation from said source thereof to pass through said intensity controlling means, approach a sample placed on said means for supporting a sample at an intended angle of incidence along a first locus, reflect from said sample, interact with said reflecting means, then, after optionally again interacting with said sample, proceed along a second locus and enter said detector; d) adjusting said intensity controlling fliter means such that said detector provides a non-saturated signal; e) causing said common support and said means for supporting a sample to be increased and positioning a test sample on said means for supporting a sample, then causing said distance between said common support and said means for supporting a sample to be decreased; f) adjusting said intensity controlling filter means such that said detector provides a non-saturated signal; and g) analyzing data provided by detector.