SPECTROMETER WITH VERTICAL DISPERSION MODE FOR STUDYING CHEMICAL-SHIFTS IN X-RAY-EMISSION LINES WITH THE USE OF SYNCHROTRON-RADIATION - PRELIMINARY EXPERIMENT

The spectrometer proposed uses white synchrotron radiation for fluores cence excitation. The fluorescence analysis is carried out by a double crystal diffractometer in the vertical dispersion mode. We simulate e xperimental data taking the uranium L(alpha 1) emission line (epsilon = 13.6 keV, Delta epsilon = 11.3 eV) and Kurchatov Synchrotron Radiati on Source parameters. We take into account the following parameters: t he partial absorption cross section of the element under investigation mu(part)(epsilon), the SR spectral distribution, the Gaussian vertica l photon angle distribution sigma(z'ph)(epsilon), and the Gaussian ver tical electron linear and angle distributions sigma(zel) and sigma(z'e l). The emission X-ray line has been taken to have a Lorentz form. The transmission coefficient of the double crystal spectrometer in high d ispersion position has been taken to have a Gauss-form sigma(Dar). The following results have been achieved. A measurement accuracy Delta ep silon/epsilon congruent to 10(-6) can be achieved when measuring for s imilar to 100 s with E = 2.5 GeV and I = 100 mk Here de is the statist ic uncertainty of the line position and epsilon is the emission line e nergy. The natural line width will not be increased by the spectromete r convolutions by more than 20%, so the line form can be investigated very carefully. Based on piezoelectric transducers, the diffractometer is now being commissioned. A preliminary experiment in vertical dispe rsion mode has been performed and fitted with the theory.