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Electron Beam Induced Luminescence Of Sio2 Optical Coatings, Jr Dennison, Amberly Evans, Gregory Wilson, Justin Dekany, Charles W. Bowers, Robert Meloy
Electron Beam Induced Luminescence Of Sio2 Optical Coatings, Jr Dennison, Amberly Evans, Gregory Wilson, Justin Dekany, Charles W. Bowers, Robert Meloy
Gregory Wilson
Optical coatings of disordered thin film SiO2/SiOx dielectric samples on reflective metal substrates exhibited cathodoluminescence under electron beam irradiation. Measurements of the absolute radiance and emission spectra as functions of incident electron energy, flux and power over a range of sample temperatures are reported. Radiance reached a saturation plateau at high incident electron power. Well below saturation radiance scaled with deposited power, that is linearly with incident power for lower-energy non-penetrating electrons and decreasing with increasing energy for penetrating radiation. Four bands were observed in spectral measurements from 300 nm to 1000 nm. Changes in peak intensity and shifts in …
Ultrahigh Vacuum Cryostat System For Extended Low Temperature Space Environment Testing, Justin Dekany, Robert H. Johnson, Gregory Wilson, Amberly Evans, Jr Dennison
Ultrahigh Vacuum Cryostat System For Extended Low Temperature Space Environment Testing, Justin Dekany, Robert H. Johnson, Gregory Wilson, Amberly Evans, Jr Dennison
Gregory Wilson
The range of temperature measurements have been significantly extended for an existing space environment simulation test chamber used in the study of electron emission, sample charging and discharge, electrostatic discharge and arcing, electron transport, and luminescence of spacecraft materials. This was accomplished by incorporating a new cryostat system and sample mount, which maintained compatibility with an existing ultrahigh vacuum chamber (base pressure The new two-stage, closed-cycle helium cryostat has an extended sample temperature range from450 K, with long-term controlled stability of The new capabilities in this chamber have been employed to study the temperature dependence of materials properties critical to …
Low Temperature Cathodoluminescence In Disordered Sio2, Amberly Evans, Gregory Wilson, Jr Dennison
Low Temperature Cathodoluminescence In Disordered Sio2, Amberly Evans, Gregory Wilson, Jr Dennison
Gregory Wilson
Disordered SiO2 is commonly used for optical instrumentation and coatings. In space telescope applications, these materials can be exposed to low temperature (particularly for IR telescopes) and simultaneous electron fluxes from the space plasma environment. During recent charging tests of this dielectric material, a discernable glow was detected emanating from the surface of the SiO2, indicating that the incident electron beam induced a luminescent effect, termed cathodoluminescence. As the sample cooled from 300 K to 120 K, a change in the intensity and energy spectrum of the glow was observed between 250 nm and 1700 nm, demonstrating that the SiO2 …