摘要:
A method is provided for screening lead concentration compliance of objects, particularly consumer products such as toys, using x-ray fluorescence (XRF) analysis. The measured intensity ratio of the characteristic Lα and Lβ x-rays of lead provides an indication of whether the lead is located primarily in a coating (e.g., paint) layer on the object, or in a thin or thick bulk material. If the intensity ratio indicates that the lead is located in a coating layer or distributed in a thin bulk material, an areal density of lead is determined from at least one of the characteristic x-ray intensities, and the measured areal density is compared to specified lower and upper limits to determine whether the object is unambiguously compliant, unambiguously non-compliant, or indeterminate.
摘要:
A method, instrument, and computer program software product for characterizing a sample with respect to the presence of a specified element, either as a constituent of a surface layer or of the bulk of the sample. Intensities of fluorescent emission at two characteristic emission lines are compared to establish whether the specified element is disposed above the bulk of the sample. In the case where the specified element is disposed above the bulk of the sample, an areal density of the specified element is determined, whereas in the case where the specified element is disposed within the bulk of the sample, a volumetric concentration of the specified element within the sample is determined.
摘要:
A hand-held, self-contained x-ray fluorescence (XRF) analyzer produces a small x-ray spot on a sample to interrogate the elemental composition of a sample region of millimeter-size characteristic dimension. The analyzer includes a collimator for aiming an x-ray beam toward a desired location on the sample and for determining the size of the spot produced on the sample. The analyzer may include a digital camera oriented toward the portion of the sample that is, or would be, interrogated by the x-ray spot to facilitate aiming the analyzer. The analyzer may generate a reticule in a displayed image to indicate the portion of the sample that is, or would be, illuminated by the x-ray beam. The analyzer may automatically annotate the image of the sample with text or graphics that contain information about the analyzed sample. The image may be stored in the hand -held analyzer or provided for external storage or display.
摘要:
A method, instrument, and computer program software product for characterizing a sample with respect to the presence of a specified element, either as a constituent of a surface layer or of the bulk of the sample. Intensities of fluorescent emission at two characteristic emission lines are compared to establish whether the specified element is disposed above the bulk of the sample. In the case where the specified element is disposed above the bulk of the sample, an areal density of the specified element is determined, whereas in the case where the specified element is disposed within the bulk of the sample, a volumetric concentration of the specified element within the sample is determined.
摘要:
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 such as to decrease with increasing radial distance from the central irradiated region of the test material.
摘要:
An apparatus for selective radiation detection includes a neutron detector that facilitates detection of neutron emitters, e.g. plutonium, and the like; a gamma ray detector that facilitates detection of gamma ray sources, e.g., uranium, and the like. The apparatus comprises a first light guide, optically coupled to a first optical detector; a second light guide, optically coupled to a second optical detector a sheet of neutron scintillator, opaque for incoming optical photons, said sheet of neutron scintillator sandwiched between the first and the second light guides. The second light guide comprises a gamma ray scintillator material.
摘要:
A method, instrument, and computer program software product for characterizing a sample with respect to the presence of a specified element, either as a constituent of a surface layer or of the bulk of the sample. Intensities of fluorescent emission at two characteristic emission lines are compared to establish whether the specified element is disposed above the bulk of the sample. In the case where the specified element is disposed above the bulk of the sample, an areal density of the specified element is determined, whereas in the case where the specified element is disposed within the bulk of the sample, a volumetric concentration of the specified element within the sample is determined.
摘要:
Multiple energy sources, such as a laser and electrical current, are employed, in close coordination, spatially and temporally, to clean a sample, vaporize its material and excite vapor atoms for the purpose of atomic emission spectroscopy. These methods permit better monitoring and control of the individual processes in real time, lead to higher consistency and higher quality optical emission spectra, and enhance the measurements of non-conducting solids, liquids and gases. Additionally, a portable instrument is provided with both laser source and spectrometer optically coupled to a hand-holdable unit.
摘要:
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.
摘要:
An x-ray fluorescence analyzer and method. The analyzer and method use a single radio-active source, such as, 241Am to determine the composition of a metal alloy or precious metal. The method compensates for Rayleigh scattering by first determining a scaling factor using a particular energy line in the spectrum of the test material and comparing that line to the same energy line for a pure metal. Based on the scaling factor the energy spectrum for the pure is compensated and then subtracted from the energy spectrum of the test material at discrete points.