Abstract: A optical engine includes a body having a top surface, an opposing bottom surface, and a sampling chamber located between the top surface and the bottom surface. A plurality of light sources extends radially from the sampling chamber such that each of the plurality of light sources extends along its own longitudinal axis. A like plurality of light traps extends radially from the sampling chamber. Each of the like plurality of light traps is associated with one of the plurality of light sources across the sampling chamber and extends along the longitudinal axis of its associated light source. An optical detector extends radially from the sampling chamber along a photomultiplier longitudinal axis. A photomultiplier light trap is diametrically opposite from the optical detector across the sampling chamber along the photomultiplier longitudinal axis. The system can also be assembled in an inverse configuration where the detector and light sources exchange positions.