Research closely related to that reported in the preceding article has shown that δ-doped charge-coupled devices (CCDs) could be used to detect incident protons and perhaps other positive ions, and to measure the kinetic energies of the ions, down to about 1.25 keV. Prior to the development of δ-doped CCDs, the minimum kinetic energy for detectability of protons by solid-state devices was about 10 keV, for the reasons described in the preceding article.
Heretofore, a typical instrument for detecting low-kinetic-energy charged particles and measuring the particle kinetic energies has comprised a relatively heavy, power-hungry electrostatic- or magnetic-energy analyzer followed by a microchannel-plate detector. In contrast, δ-doped CCDs offer the capability for measuring kinetic energies directly in the detection process, without need for electrostatic or magnetic energy analyzers; this opens up the possibility of developing simpler, smaller, low-power-consumption instruments for measuring low-kinetic-energy charged particles.
An experiment was performed to demonstrate the use of a δ-doped CCD to detect incident protons and measure their kinetic energies. A δ-doped CCD with associated camera electronics was placed in a vacuum chamber, attached to a magnetically analyzed low-kinetic-energy proton-beam apparatus. The responses of the CCD were then measured at proton kinetic energies from 12 down to 1.25 keV. The CCD output signals were found to vary monotonically with proton kinetic energy throughout the energy range of the experiment.
This work was done Shouleh Nikzad, Stythe Elliott, Thomas Cunningham, Walter Proniewicz, D. R. Croley, G. B. Murphy, and Dale Winther of Caltech forNASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.comunder the Electronic Components & Circuits category.
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