INVESTIGATION OF GAS SPECIES GENERATED IN THE PHOTOEMISSION SPECTROSCOPY SYSTEM AT THE SIAM PHOTON LABORATORY
Abstract
This report describes the design of the vacuum system of the photoemission spectroscopy system installed at the first beamline of the Siam Photon Laboratory, and shows the results from the investigation of gas species generated in the system. The base vacuum pressure of the system after the well bake-out processes is approximately 2 × 10-10 mbar. The vacuum pressure increases more than one order of magnitude when there is a linear movement of the sample manipulator or when the UV lamp, the electron gun or the X-ray source is operated. The gas species generated in the system were analyzed by the quadrupole mass spectrometer. Adsorption of the gas molecules on a clean well-defined Ni(111) surface has been observed by low-energy electron diffraction and Auger electron spectroscopy measurements.
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