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AssigneeMax-Planck-Gesellschaft
InventorsThomas Schedel-Niedrig, Axel Knop-Gericke, Michael Havecker
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In order to investigate the reactants involved in a reaction between a gas and a solid by means of X-ray absorption spectroscopy an apparatus is provided which comprises, within a measuring chamber (2), a sample holder (23) for holding a sample (24) of the solid, means for forming an atmosphere of the gas in the measuring chamber under selectable pressure, a window (20) for the entry of X-rays for the irradiation of the sample (24) and a collector arrangement (21, 22) arranged spaced from the sample holder (23), in order to collect in the measuring chamber (2) electrons released by X-ray absorption. The collector arrangement comprises two collector electrodes (21 and 22) which are arranged mutually spaced from one another in sequence lengthwise along the X-ray path between the window (20) and the sample holder (23). Each collector electrode (21, 22) and the sample holder (23) have respective connection means (31, 32, 33) for the connection of each to a respective associated predetermined potential and for the separate measurement of the currents (I1, I2, I3) flowing through these connections. By evaluation of these currents evidentially helpful spectra of the involved reactants can be obtained both at and adjacent to the sample surface and also in the gas phase within the range of soft X-rays.
Apparatus for the investigation of the reactants involved in a reaction between a gas and a solid by means of X-ray absorption spectroscopy, comprising a measuring chamber (2) with
Apparatus according to one of the preceding claims, in which at least one of the collector electrodes (21, 22) comprises an electrode grating in the path of the X-rays which is penetratable by the X-rays.
Apparatus according to one of the preceding claims, in which the distance (d3) measured in the beam direction between the surface of the sample which is irradiated by the X-rays and the collector electrode (22) which is closer to the sample lies within the range of about once up to about four times the distance (d2) between the two collector electrodes (21, 22).
Apparatus according to one of the preceding claims, in which the window (20) is penetrable by soft X-rays in the photon energy range of 100 up to 1000 eV.
Apparatus according to one of the preceding claims, in which the sample holder (23) contains a heating means (23c) for the controllable heating of the sample (24) within the range of up to about 1000° K.
Apparatus according to one of the preceding claims, in which the window (20) has connected in advance of it a UHV chamber (1) through which the X-rays are arranged to pass, and wherein a device (11) for the measurement of the intensity (I0) of the X-rays directed towards the window (20) is provided in the UHV chamber.
Dependencies are inferred from the claim text.