STP1117

    Measurements of UV Induced Absorption in Dielectric Coatings

    Published: Jan 1990


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    Abstract

    We discuss the first results obtained from a new testing facility for measuring the induced absorption in multilayer dielectric coatings exposed to intense UV radiation. The absorption loss is measured in-situ during exposure, as a function of time for various UV photon energies, intensities, and sample materials. The sample is irradiated by the direct beam from the TOK undulator at NSLS and measured in-vacuo. The undulator is typically run at K = 1 (so that the harmonic emission is low) to simplify the data analysis. The test chamber is separated from the undulator beamline by a differentially pumped line which permits the introduction of carbonaceous gases into the chamber at pressures up to 10-5 Torr. By varying the current and energy of the stored electrons, one can adjust the intensity and photon energy of the undulator first harmonic in the range up to 1.2 w/cm2, and between about 5 eV and 35 eV.

    Keywords:

    damage, dielectric coatings, free electron laser, harmonics, lossmeter, multilayer, optics, UV induced absorption


    Author Information:

    Bakshi, MH
    Deacon Research, Palo Alto, CA

    Cecere, M
    Deacon Research, Palo Alto, CA

    Deacon, DAG
    Deacon Research, Palo Alto, CA

    Fauchet, AM
    NSLS, Brookhaven National Lab, Upton, NY


    Paper ID: STP26520S

    Committee/Subcommittee: E13.15

    DOI: 10.1520/STP26520S


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