Abstract: A probe for a spectrometer has a slot for receiving a sample, an illuminating fiber optic bundle directing light to the sample in the slot, and first and second collecting fiber optic bundles transmitting light from the sample to the spectrometer, wherein the first collection fiber optic bundle is positioned to optimize the collection of transmitted light without scattering through the sample, and the second collection fiber optic bundle is positioned to optimize the collection of light diffusely reflected from the sample. In one embodiment, the first collection bundle is arranged in an annulus around the illuminating bundle, and the second collection bundle is arranged in an annulus around the first collection bundle. In a second embodiment, the second collection bundle is arranged in an annulus around the illuminating bundle, and the first collection bundle terminates in an interface with the sample located across the slot from the illuminating bundle and the second collection bundle.

Abstract: In a system for measuring moisture content of powder, such as powdered milk while the powder is being dried, the powder is contained in a fluidized bed and a fiber optic probe is inserted through the wall of the container of said bed to be immersed in the fluidized bed. The fluidized bed continuously scrubs the outer surface of the probe window and prevents it from being coated with the powder. Near infrared light is transmitted through a cable optic fiber and said probe to irradiate the powder in said fluidized bed and is reflected back from the powder into said probe and transmitted by said fiber optic cable to a spectroscopic analyzing instrument. The fiber optic probe includes a sapphire rod having a back surface abutting the end of the fiber optic cable and an angled front surface. The front of the probe is closed by a quartz window spaced from the angled front surface of the sapphire rod and held in position by an inwardly directed flange on the outer tubular casing of the fiber optic probe.