Vacuum apparatuses have been developed for increasing the range of elements that can be identified by use of x-ray fluorescent (XRF) scanners of the type mentioned in the two immediately preceding articles. As a consequence of the underlying physical principles, in the presence of air, such an XRF scanner is limited to analysis of chlorine and elements of greater atomic number. When the XRF scanner is operated in a vacuum, it extends the range of analysis to lower atomic numbers — even as far as aluminum and sodium. Hence, more elements will be available for use in XRF labeling of objects as discussed in the two preceding articles.
The added benefits of the extended capabilities also have other uses for NASA. Detection of elements of low atomic number is of high interest to the aerospace community. High-strength aluminum alloys will be easily analyzed for composition. Silicon, a major contaminant in certain processes, will be detectable before the process is begun, possibly eliminating weld or adhesion problems. Exotic alloys will be evaluated for composition prior to being placed in service where lives depend on them. And in the less glamorous applications, such as bolts and fasteners, substandard products and counterfeit items will be evaluated at the receiving function and never allowed to enter the operation.
Both hand-held and tabletop XRF portable scanners have been developed. The vacuum apparatus is compact and lightweight and does not detract from the portability of either XRF scanner. It is attached to and detached from the aperture end of either XRF scanner.
The upper part of the figure schematically depicts the hand-held XRF scanner. The XRF scanner and vacuum apparatus would be connected to a portable (beltmounted) control unit that would contain a power supply and a vacuum pump. The lower part of the figure is a simplified, enlarged cross-sectional view of a vacuum apparatus attached to the aperture end of the XRF scanner. The side wall of the vacuum apparatus would include a flexible portion that would support a seal flange and seal bead, which would be pressed against an object to be scanned to form an air-tight seal. While holding the seal and pressing the aperture of the XRF scanner against the object to be scanned, the operator would press a switch, thereby starting the process. The switch would turn on the pump and keep it on for as long as needed to maintain the vacuum needed for the XRF scan.
The vacuum enhanced version of the hand-held XRF, already in use in the shuttle program, takes the chemistry lab to the shop floor, something that was not practical to do before with large products such as external tanks, space shuttle main engines, and solid rocket boosters. From label scanning to material analysis, the vacuum enhanced XRF is a welcome addition to the NASA toolbox of capabilities.
In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:
Keymaster Technologies, Inc.
415 N. Quay Street, Suite 1
Kennewick, WA 99336
Refer to MFS-31898, volume and number of this NASA Tech Briefs issue, and the page number.