Geometrical beam splitter and a sensor for multi-element detectors

A sensor comprising:

• a radiation source;
• a measuring chamber, and
• a geometrical beam splitter composed of a piece of rigid material, with
• at least one hole extending through said piece of rigid material, said hole passing a transversal beam portion into at least a first detector,
• a non-transparent reflective surface on said piece of rigid material reflecting at least two transversal beam portions into at least a second and a third detector, and
• a width and a height extending over a total effective cross-sectional area of the radiation beam necessitated by the detectors;
• whereupon a radiation beam from said radiation source travels to said at least three detectors through the measuring chamber, said beam splitter positioned between the detectors and the measuring chamber so as to allow a reflected portion and an undiverted portion of said radiation beam to reach the detectors simultaneously, wherein in said beam splitter:
• said at least one hole has/have length(s) at least equal with the diameter of the holes forming wavetube(s) for the transversal beam portion(s) passing through the hole(s);
• and
• said non-transparent reflective surface has such continuous surface dimensions around said at least one hole, and said hole(s) has/have such diameter(s), which allow reflectance and respectively passing of said beam portions with substantially similar wavelength distributions, concentrating the sensitivies of the detectors to receive radiation substantially from a common area or volume of the measuring chamber.