Presentation Mo-coated grating-based beam intensity monitor for 13.9 nm x-ray laser

今園, 孝志  ,  西原弘晃  ,  浮田龍一  ,  笹井浩行  ,  長野哲也

We report a high-efficiency beam intensity monitoring device for a 13.9 nm Ni-like Ag laser. A gold-coated holographic grating with 1200 lines/mm (Shimadzu, #30-002) was merely overcoated with a 16 nm-thick Mo layer for the sake of the diffraction efficiency improvement. The performance was examined by measurements of absolute diffraction efficiencies with synchrotron radiation, and the improvement effect by Mo coating was confirmed: from 69.5% and 8.7% for the zeroth and first orders, respectively, to 74.6% and 13.0%. In addition, it became clear that a high correlation between the intensities of the zeroth and first diffraction orders of the Mo grating measured with the 13.9 nm x-ray laser (XRL) was obtained, being 0.997. Moreover, we have determined a degree of linear polarization of the XRL beam by soft x-ray polarimetry and have validated the practicality of the Mo grating-based beam intensity monitor.
13th International Conference on Synchrotron Radiation Instrumentation (SRI2018)

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