Abstract: A portable x-ray fluorescence spectrometer has a portable sensor unit containing a battery, a high voltage power supply, an x-ray tube which produces a beam x-ray radiation directed toward a target sample, and a detector for fluorescent x-rays produced by the sample. If a silicon-lithium detector is used, the sensor unit also contains either a thermoelectric or thermochemical cooler, or a small dewar flask containing liquid nitrogen to cool the detector. A pulse height analyzer ("PHA") generates a spectrum of data for each sample consisting of the number of fluorescent x-rays detected as a function of their energy level. The PHA can also store spectrum data for a number of samples in the field. A processing unit can be attached to the pulse height analyzer to upload and analyze the stored spectrum data for each sample.

Abstract: A liquid sample holder having a fluid sample receptacle bounded by two substantially parallel sheets. The parallel sheets define a fluid analysis area, and adjacent to that area is a peripheral overflow. Air bubbles are trapped in the peripheral overflow because the distance between the plates is smaller than the depth or thickness of the peripheral overflow.

Abstract: A semi-automatic quantitative filtration assembly is disclosed having a measuring means to measure and present a known quantity of fluid for filtering and a fluid holding means adjacent to a filter medium. The fluid holding means is adapted to receive and hold excess fluid during filtering and to prevent intermixing with a known quantity of fluid to be presented to filtering. The filtering apparatus is designed to filter a quantitative amount of fluid and receive fluid in the fluid holding tank which is excess sample fluid or fluid unwanted as a result of error or operational failure and which drains to a common vacuum/waste means for filtered fluid. A variety of features are also provided to insure proper operation and minimize operator error.

Abstract: A field portable X-ray fluorescent spectrometer is described including a multichannel analyzer (2) and a plurality of interchangeable sensor heads (4). Each sensor head includes a shutter (100) which, when open, permits one of several radiation sources (80, 82) to irradiate a material to be analyzed. The returned radiation is detected by a corresponding detector (86, 90), which provides corresponding data in response. This shutter has calibration plaques attached to it so that, when closed, the plaques are exposed to the radiation sources and return radiation having selected energy distributions to the detectors. The multichannel analyzer uses the resulting detector data to calibrate the sensor head. Each sensor head includes circuitry (290) for identifying itself to the multichannel analyzer. The analyzer automatically adapts its operation in accordance with this identification.

Abstract: A proximity sensor utilizing nucleonic radiation fluorescence to detect the presence, position and/or distance of a target object from a monitoring object. The inventive system has particular application in collision avoidance systems for subsatellites, final docking alignment systems in spacecraft applications, collision avoidance systems for teleoperated manipulative arms, homing devices for manipulative devices as well as hazard detection systems for planatary rovers. Where necessary, the target object is fitted with cooperative radiation fluorescent material. The monitoring object looks for and detects the preselected fluorescence, thus discriminating between radiation emitted by the target object and extraneous radiation.