Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Publication
- Publication Type
- File Type
Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
Diverse Electron-Induced Optical Emissions From Space Observatory Materials At Low Temperatures, Jr Dennison, Amberly Evans Jensen, Gregory Wilson, Justin Dekany, Charles W. Bowers, Robert H. Meloy
Diverse Electron-Induced Optical Emissions From Space Observatory Materials At Low Temperatures, Jr Dennison, Amberly Evans Jensen, Gregory Wilson, Justin Dekany, Charles W. Bowers, Robert H. Meloy
Conference Proceedings
Electron irradiation experiments have investigated the diverse electron-induced optical and electrical signatures observed in ground-based tests of various space observatory materials at low temperature. Three types of light emission were observed: (i); long-duration cathodoluminescence which persisted as long as the electron beam was on (ii) short-duration (<1 s) arcing, resulting from electrostatic discharge; and (iii) intermediate-duration (~100 s) glow—termed “flares”. We discuss how the electron currents and arcing—as well as light emission absolute intensity and frequency—depend on electron beam energy, power, and flux and the temperature and thickness of different bulk (polyimides, epoxy resins, and silica glasses) and composite dielectric materials (disordered SiO2 thin films, carbon- and fiberglass-epoxy composites, and macroscopically-conductive carbon-loaded polyimides). We conclude that electron-induced optical emissions resulting from interactions between observatory materials and the space environment electron flux can, in specific circumstances, make significant contributions to the stray light background that could possibly adversely affect the performance of space-based observatories.
Power And Charge Deposition In Multilayer Dielectrics From Monoenergetic Electron Bombardment, Gregory Wilson, Amberly Evans, Justin Dekany, Jr Dennison
Power And Charge Deposition In Multilayer Dielectrics From Monoenergetic Electron Bombardment, Gregory Wilson, Amberly Evans, Justin Dekany, Jr Dennison
Gregory Wilson
Power and charge deposition in multilayer dielectrics from electron bombardment is dependent upon the flux and electron range of the electron beam, where the range,--a lso known as the penetration depth—is dependent upon the incident beam energy. Using the Continuous Slow Down Approximation (CSDA), a composite analytical formula has been developed to relate the electron range to the dose rate and subsequently to the deposited power in each subsequent layer. Based on the constituent layer geometry and material , the deposited charge can also be inferred. To validate these models two separate experiments were conducted, one based on the net …
Temperature Dependence Of Sio2 Electron-Induced Cathodoluminescence, Amberly Evans, Gregory Wilson, Jr Dennison
Temperature Dependence Of Sio2 Electron-Induced Cathodoluminescence, Amberly Evans, Gregory Wilson, Jr Dennison
Gregory Wilson
No abstract provided.
Low Temperature Cathodoluminescence Of Space Observatory Materials, Amberly Evans, Gregory Wilson, Justin Dekany, Alec Sim, Jr Dennison
Low Temperature Cathodoluminescence Of Space Observatory Materials, Amberly Evans, Gregory Wilson, Justin Dekany, Alec Sim, Jr Dennison
Gregory Wilson
In recent charging studies, a discernable glow was detected emanating from sample surfaces undergoing electron beam bombardment that resulted from a luminescent effect termed cathodoluminescence. This suggests that some of the materials used as optical elements, structural components, and thermal control surfaces in the construction of space-based observatories might luminesce when exposed to sufficiently energetic charged particle fluxes from the space plasma environment. If these visible, infrared and ultraviolet emissions are intense enough, they can potentially produce optical contamination detrimental to the performance of the observatory optical elements and sensors, and act to limit their sensitivity and performance windows. As …
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 …
Low Temperature Cathodoluminescence Of Space Observatory Materials, Amberly Evans, Gregory Wilson, Justin Dekany, Alec Sim, Jr Dennison
Low Temperature Cathodoluminescence Of Space Observatory Materials, Amberly Evans, Gregory Wilson, Justin Dekany, Alec Sim, Jr Dennison
Justin Dekany
In recent charging studies, a discernable glow was detected emanating from sample surfaces undergoing electron beam bombardment that resulted from a luminescent effect termed cathodoluminescence. This suggests that some of the materials used as optical elements, structural components, and thermal control surfaces in the construction of space-based observatories might luminesce when exposed to sufficiently energetic charged particle fluxes from the space plasma environment. If these visible, infrared and ultraviolet emissions are intense enough, they can potentially produce optical contamination detrimental to the performance of the observatory optical elements and sensors, and act to limit their sensitivity and performance windows. As …
Power And Charge Deposition In Multilayer Dielectrics From Monoenergetic Electron Bombardment, Gregory Wilson, Amberly Evans, Justin Dekany, Jr Dennison
Power And Charge Deposition In Multilayer Dielectrics From Monoenergetic Electron Bombardment, Gregory Wilson, Amberly Evans, Justin Dekany, Jr Dennison
Justin Dekany
Power and charge deposition in multilayer dielectrics from electron bombardment is dependent upon the flux and electron range of the electron beam, where the range,--a lso known as the penetration depth—is dependent upon the incident beam energy. Using the Continuous Slow Down Approximation (CSDA), a composite analytical formula has been developed to relate the electron range to the dose rate and subsequently to the deposited power in each subsequent layer. Based on the constituent layer geometry and material , the deposited charge can also be inferred. To validate these models two separate experiments were conducted, one based on the net …
A Multiphase Strategy For Realizing Green Cathodoluminescence In 12cao·7al2o3–Caceal3o7:Ce3+,Tb3+ Conductive Phosphor, Xiuling Liu, Yuxue Liu, Duanting Yan, Hancheng Zhu, Chunguang Liu, Weizhen Liu, Changshan Xu, Yichun Liu, Hong Zhang, Xiao-Jun Wang
A Multiphase Strategy For Realizing Green Cathodoluminescence In 12cao·7al2o3–Caceal3o7:Ce3+,Tb3+ Conductive Phosphor, Xiuling Liu, Yuxue Liu, Duanting Yan, Hancheng Zhu, Chunguang Liu, Weizhen Liu, Changshan Xu, Yichun Liu, Hong Zhang, Xiao-Jun Wang
Department of Physics and Astronomy Faculty Publications
A multiphase strategy is proposed and successfully applied to make the insulating green phosphor CaCeAl3O7:Tb3+ conductive in the form of 12CaO·7Al2O3–CaCeAl3O7:Ce3+,Tb3+. The phosphor shows bright green-light emission with a short lifetime (2.51 ms) under low-voltage electron beam excitation (3 kV). The green photo- and cathodoluminescence from 5D4–7FJ (J = 6, 5, 4, 3) transitions of Tb3+ are significantly enhanced in comparison with pure C12A7:Tb3+. It was confirmed that this enhancement is the consequence …
Properties Of Cathodoluminescence For Cryogenic Applications Of Sio2-Based Space Observatory Optics And Coatings, Amberly Evans Jensen, Jr Dennison, Gregory Wilson, Justin Dekany, Charles Bpwers, Robert Meloy, James B. Heaney
Properties Of Cathodoluminescence For Cryogenic Applications Of Sio2-Based Space Observatory Optics And Coatings, Amberly Evans Jensen, Jr Dennison, Gregory Wilson, Justin Dekany, Charles Bpwers, Robert Meloy, James B. Heaney
Conference Proceedings
Disordered thin film SiO2/SiOx coatings undergoing electron-beam bombardment exhibit cathodoluminescence, which can produce deleterious stray background light in cryogenic space-based astronomical observatories exposed to high- energy electron fluxes from space plasmas. As future observatory missions push the envelope into more extreme environments and more complex and sensitive detection, a fundamental understanding of the dependencies of this cathodoluminescence becomes critical to meet performance objectives of these advanced space-based observatories. Measurements of absolute radiance and emission spectra as functions of incident electron energy, flux, and power typical of space environments are presented for thin (~60-200 nm) SiO2/SiOx optical coatings on reflective metal …