We discuss the first results obtained from a new testing fa- cility for measuring the induced absorption in multilayer dielec- tric coatings exposed to intense UV radiation. The absorption loss is measured in-situ during exposure, as a function of time for var- ious 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 anal- ysis. The test chamber is separated from the undulator beamline by a differentially pumped line which permits the introduction of car- bonaceous gases into the chamber at pressures up to 10-5 Torr. By varying the current and energy of the stored electrons, one can ad- just 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.
M. H. Bakshi, M. H. Bakshi,
"Measurements of UV induced absorption in dielectric coatings", Proc. SPIE 1438, Laser-Induced Damage in Optical Materials 1989, 14381G (1 November 1990); doi: 10.1117/12.2294461; https://doi.org/10.1117/12.2294461