Patent ID: 6870615

Claim:
A modular dual beam source, sample compartment and beam-combining system that can be used together with any monochromator or spectral filter and detector having the desired spectral coverage so the combination can be used as a spectrophotometer consisting of: (a) a source module having a shutter, wherein a single light source is reimaged the same distance from the source by a pair of mirror image, off-axis, ellipsoidal mirrors down two parallel paths to form two images of the light source, and either (b1) a reflecting sample compartment module with two halves wherein one half the re-imaged light from the source falls in between two plane mirror surfaces, one of which is the sample to be measured and the other a reference surface, and in the other half the re-imaged light falls similarly in between two plane mirrors, both of which are reference surfaces, or (b2) a transmission sample compartment module with two halves wherein one half the re-imaged light from the source falls in between two plane mirror surfaces between which the sample to be measured is placed normal to the beam, while the other half is identical but has no sample, and (c) a beam-combining module wherein the two images of the source having traversed one of the sample compartment modules, are re-imaged at approximately 1:1 by a pair of mirror image off-axis ellipsoidal mirrors on a reflective chopper that recombines the re-imaged source at a single location that is then re-image again at 1:1 by another off-axis ellipsoidal mirror to a focus external to the module, each module being kinematically located with respect to each other so that the system remains optically aligned when the modules are interchanged.