Abstract: Two or more high-frequency microphones are used to determine where an individual spark or other excitation beam strikes a sample in an optical emission spectroscopy (OES) instrument. The position of the spark can be correlated with the elemental composition of the material in the sample vaporized by the spark. The microphones are placed appropriately in air around a sparker of the instrument, or appropriately on the sample, or on both the sample and in the air. Arrival times of sound from the spark to the microphones, or a difference in the arrival times, yields information, from which the position of the spark relative to the microphones, and hence the absolute position of the spark, is deduced, such as by triangulation. Optionally or in addition, a signal that indicates a time when the spark is produced is correlated with one or more spectra detected by a spectrometer, so a spectrum that results from the vaporized sample can be distinguished from a spectrum that results from heated gas above the sample.

Abstract: A radiation shield and method for reducing ambient radiation levels at a distance from a surface irradiated by penetrating radiation emanating from an instrument substantially along a propagation axis. The shield attaches to an end of the instrument proximate to an irradiated surface and has a surface of attenuating material disposed with a component extending outward from the propagation axis of penetrating radiation and substantially adjacent to the irradiated surface.

Abstract: An instrument and method for measuring the elemental composition of a test material. The instrument has a source of penetrating radiation for irradiating an irradiated region of the test material, a detector for detecting fluorescence emission by the test material and for generating a detector signal, and a controller for converting the detector signal into a spectrum characterizing the composition of the test material. A platen of attenuating material extends outward from adjacent to, and surrounding, the irradiated surface of the test material. In certain embodiments, the thickness of the attenuating platen is tapered with increasing radial distance from the central irradiated region of the test material.

Abstract: A method for obtaining a concentrated, monochromatic x-ray beam from a standard x-ray tube or other source of polychromatic emission. X-rays from the anode of the x-ray tube fluoresce an adjoining, independent target that produces a monochromatic spectrum, a portion of which is focused by the x-ray optical system. This two-stage method gives the system considerably versatility without undue loss in signal. The two-stage concentrator makes practical the use of focusing optics in hand-held and portable instruments.

Abstract: A method and computer program software product for establishing an areal density of an elemental constituent of one layer of a stack of layers of material overlying a substrate. Incident penetrating radiation excites characteristic x-ray fluorescent radiation in multiple lines associated with each of one or more elements. Areal densities of successive layers are determined by self-consistent solution of equations relating the ratios of intensities of the characteristic fluorescence lines of successive elements.