No abstract

This report presents the design of an undulator beamline at SPring-8 to be used for soft X-ray spectroscopy focused on radioactive materials. Photoemission spectroscopy experiments are carried out in a radioisotope (RI)-controlled area where actinide compounds as well as unsealed radioactive materials are usable. Intrusion of the radioactive materials into the electron storage ring or to the outside of the evacuated beamline components can be avoided by a specially devised RI protection/ inspection mechanism. The combination of a variably polarizing undulator and a varied-line-spacing plane-grating monochromator provides linearly or circularly polarized soft X-rays with a high resolving power in the energy range 0.28-1.5 keV. The beamline will become operational in December 1997.

Symmetry-resolved" photoabsorption spectra of free N2 molecules in the K-shell excitation region have been obtained using a technique of angle-resolved photoion spectroscopy combined with linearly polarized undulator radiation. The obtained Xand II-symmetry component spectra have nicely demonstrated the symmetry decomposition of the photoabsorption spectrum. These spectra have been compared with theoretical calculations in the photon-energy regions below and above the ionization threshold.PACS number(s): 33.80.Eh, 33.80.Gj

Symmetry-resolved photoabsorption spectra measured at the C and 0 E edges of CO have demonstrated the symmetry decomposition of the conventional photoabsorption spectra. These spectra have been compared with theoretical calculations in the K-shell ionization continua. Definite assignments for the symmetries have been given in the photon-energy regions below and above the E-shell ionization thresholds.PACS number(s): 33.80.Eh, 33.80.Gj