Field portable element analysis unit

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. When the shutter is open, the multichannel analyzer utilizes the detector data to accumulate an energy spectrum of the material being analyzed, and displays the spectrum on a display screen (12). A cursor control (28) allows the operator to move a cursor along the displayed spectrum. A display (32) is automatically provided with a display of the symbol of the element, if any, having its major spectral peak at the position identified by the cursor. Secondary indications identify other positions along the spectrum at which peaks would appear if the element were present. Memory (202) is provided for storing a number of reference spectra, any of one of which may be displayed on the screen along with the acquired spectrum for comparison purposes. The memory (202) also stores previously acquired spectra for later analysis. The analyzer also includes other operational features, such as normalization, window control, and ratio and concentration determination, to permit the operator to quantitatively analyze materials in the field.