摘要:
A handheld X-ray diffractometer comprises a miniaturized X-ray source and multiple area detectors to allow the diffractometer to obtain two-dimensional X-ray diffraction images in a large diffraction space without rotating the sample. The source and detectors are located inside of a radio opaque enclosure that protects the operator during use. The handheld diffractometer also comprises a sample monitoring and alignment system that allows an operator to observe the measuring area and to align the diffractometer to the sample from outside of the housing. A specially designed mouthpiece, which mates the diffractometer to the sample area, prevents x-ray leakage and triggers off the data collection. The detectors can be positioned to perform measurements necessary to calculate a mechanical stress in the sample. Linear detectors may also be used in place of the area detectors.
摘要:
An X-ray detector is formed with a geometry in the form of a spherical polygon, including an entrance window, a grid and an anode. The spherical polygonal entrance window and the grid form a spherical polygonal drift region between them. The electric field in this region is radial and eliminates parallax broadening. A spherical polygonal amplification region between a resistive anode on an insulating support and the grid allows very high gas amplification and good protection against spark discharges. A readout electrode on the back side of the anode insulator detects induced charges and protects the readout electronics against sparks.
摘要:
A multiple wavelength X-ray source includes an electron-generating cathode and an anode with multiple target regions, each of which emits X-rays at a different characteristic wavelength in response to the electrons. The different X-ray radiation outputs are focused by different focusing sections of a focusing optic. The multiple focusing sections are in different respective locations, and each focuses its respective X-ray radiation onto a sample. The focusing sections may be side-by-side mirrors in a Kirkpatrick-Baez configuration, or in a single-bounce, doubly curved elliptical configuration.
摘要:
An x-ray mirror provides focusing and monochromatization while maintaining a high degree of reflectivity. The mirror has at least two mirror portions, one with a multilayer surface that provides the desired monochromating, and the other with a total external reflection surface. The multiple surfaces combine to provide the desired focusing of the x-rays from a source to a focus point. A variety of configurations may be used, each of which does the desired focusing and monochromatization with minimal energy loss. Relative positioning of the mirror portions may also allow for adjustment of the focus length.
摘要:
An x-ray source provides both a line focus output and a point focus output, and is mounted on a rotatable support to allow easy changing between the two. A housing has ports at different angular positions relative to an anode, and each port has an associated optic appropriate for an x-ray beam passing through that port. Three or four ports may also be used to allow for different types of beam conditioning. The different beam optics may also do conditioning based on wavelength, and the anode may be of a composite material to provide different wavelength ranges. The rotatable support may be manual or motorized, and a lockout mechanism may be used to ensure that only one port is active at a time. The support may also be located on a movable table that is movable in multiple perpendicular directions.
摘要:
A biological crystal formation screening apparatus uses an x-ray diffraction technique to analyze the sample containers of a sample tray for the presence of crystal formation. An x-ray source is directed toward a sample under investigation, and a two-dimensional x-ray detector is located to receive any diffracted x-ray energy. A positioning apparatus allows the different sample containers of a tray to be sequentially aligned with the source and detector, allowing each to be examined. The sample container is arranged such that a sample is located relative to the well solution so that the x-ray beam is directed to the sample without being incident on the well solution.
摘要:
A detection system for wavelength-dispersive and energy-dispersive spectrometry comprises an X-ray detector formed from a solid-state avalanche photodiode with a thin entrance window electrode that permits the efficient detection of X-rays scattered from “light” elements. The detector can be tilted relative to the incident X-rays in order to increase the detection efficiency for X-rays scattered from “heavy” elements. The entrance window may be continuous conductive layer with a thickness in the range of 5 to 10 nanometers or may be a pattern of conductive lines with “windowless” areas between the lines. A signal processing circuit for the avalanche photodiode detector includes an ultra-low noise amplifier, a dual channel discriminator, a scaler and a digital counter. A linear array of avalanche photodiode detectors is used to increase the count rate of the detection system.
摘要:
A handheld X-ray diffractometer comprises a miniaturized X-ray source and multiple area detectors to allow the diffractometer to obtain two-dimensional X-ray diffraction images in a large diffraction space without rotating the sample. The source and detectors are located inside of a radio opaque enclosure that protects the operator during use. The handheld diffractometer also comprises a sample monitoring and alignment system that allows an operator to observe the measuring area and to align the diffractometer to the sample from outside of the housing. A specially designed mouthpiece, which mates the diffractometer to the sample area, prevents x-ray leakage and triggers off the data collection. The detectors can be positioned to perform measurements necessary to calculate a mechanical stress in the sample. Linear detectors may also be used in place of the area detectors.
摘要:
An X-ray detector includes one or more photodetectors embedded in scintillating material. The photodetectors may have a needle-like, a column-like, or a ridge-like structure. The scintillating material is applied over the photodetector which can either be a p−i−n type diode, an n−i−p type diode, a Schottky diode, or an avalanche diode.
摘要:
A cryogenic transfer vial for storing and loading a crystal sample on a goniometer includes a cryogen retainer that inhibits spillage of the cryogen when the vial is inverted during sample loading and retrieval. The retainer may be an adsorptive material located in a region of the vial near a sample location, or may be a baffle arrangement within the vial for containing the cryogen.