Delta-doped, back-illuminated charge-coupled devices (CCDs) are used as detector arrays in high-performance double- focusing miniature mass spectrometers of Mattauch-Herzog design (described below). The uses of delta-doped CCD detector arrays eliminates the need for microchannel plates (MCPs) and the high-voltage power supplies, that, heretofore, have been used in detection schemes in mass spectrometers; this makes it possible to reduce the sizes, masses, and power demands of mass spectrometers. The use of delta-doped CCDs enables the direct and simultaneous measurement of ions with different masses separated along the focal plane.
In a conventional mass spectrometer, charged particles (ions) are dispersed through a magnetic sector onto an MCP at an output (focal) plane. In the MCP, the impinging charged particles excite electron cascades that afford signal gain. Electrons leaving the MCP can be read out by any of a variety of means; most commonly, they are post-accelerated onto a solid-state detector array, wherein the electron pulses are converted to photons, which, in turn, are converted to measurable electric-current pulses by photodetectors. Each step in the conversion from the impinging charged particles to the output current pulses reduces spatial resolution and increases noise, thereby reducing the overall sensitivity and performance of the mass spectrometer. Hence, it would be preferable to make a direct measurement of the spatial distribution of charged particles impinging on the focal plane.
The utility of delta-doped CCDs as detectors of charged particles was reported in two articles in NASA Tech Briefs, Vol. 22, No. 7 (July 1998): “Delta-Doped CCDs as Low-Energy-Particle Detectors” (NPO-20178) on page 48 and “Delta-Doped CCDs for Measuring Energies of Positive Ions” (NPO-20253) on page 50. In the present developmental miniature mass spectrometers, the above mentioned miniaturization and performance advantages contributed by the use of delta-doped CCDs are combined with the advantages afforded by the Mattauch-Herzog design. The Mattauch-Herzog design is a double-focusing spectrometer design involving an electric and a magnetic sector, where the ions of different masses are spatially separated along the focal plane of magnetic sector. A delta-doped CCD at the focal plane measures the signals of all the charged-particle species simultaneously at high sensitivity and high resolution, thereby nearly instantaneously providing a complete, high-quality mass spectrum. The simultaneous nature of the measurement of ions stands in contrast to that of a scanning mass spectrometer, in which abundances of different masses are measured at successive times.
This work was done by Shouleh Nikzad, Todd Jones, April Jewell, and Mahadeva Sinha of Caltech for NASA’s Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Physical Sciences category.
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:
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Refer to NPO-41378, volume and number of this NASA Tech Briefs issue, and the page number.
This Brief includes a Technical Support Package (TSP).
Delta-Doped CCDs as Detector Arrays in Mass Spectrometers
(reference NPO-41378) is currently available for download from the TSP library.
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Overview
The document titled "Delta-Doped CCDs as Detector Arrays in Mass Spectrometers" is a Technical Support Package from NASA's Jet Propulsion Laboratory (JPL), specifically identified as NPO-41378. It outlines advancements in detector technology that can significantly enhance the performance of mass spectrometers, which are critical instruments used in various scientific and industrial applications for analyzing the composition of substances.
The focus of the document is on delta-doped charge-coupled devices (CCDs), which are proposed as innovative detector arrays for mass spectrometry. Delta doping is a technique that improves the efficiency and resolution of CCDs by creating a highly controlled layer of dopants within the semiconductor material. This innovation allows for better detection of ions and enhances the overall sensitivity and resolution of mass spectrometers, making them more effective for a range of applications, including environmental monitoring, pharmaceuticals, and space exploration.
The document emphasizes the potential of these delta-doped CCDs to enable the development of high-resolution, miniature mass spectrometers. Such devices could lead to more compact and portable analytical tools, which are particularly valuable in fieldwork and remote sensing applications. The advancements discussed are part of NASA's Commercial Technology Program, aimed at disseminating aerospace-related developments that have broader technological, scientific, or commercial implications.
Additionally, the document provides contact information for further inquiries, directing interested parties to the Innovative Technology Assets Management office at JPL. It also includes a disclaimer regarding the use of the information, stating that the U.S. Government does not assume liability for its application and that any trade names mentioned are for identification purposes only.
In summary, this Technical Support Package presents a significant technological advancement in mass spectrometry through the use of delta-doped CCDs, highlighting their potential to improve detection capabilities and facilitate the creation of more compact analytical instruments. The document serves as a resource for researchers and industry professionals interested in the latest innovations in mass spectrometry technology.
