RIXS DEVELOPMENT

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. During the year 2005 we implemented a new table to support the RIXS spectrometer. A table top (Newport IG-46-2) has been purchased and installed on four stabilizer pneumatic isolators (Newport I-2000). This monolithic platform house both sample holder and spectrometer and ease the difficulty of the initial table alignment and reduce the spectrometer setup time. Another improvement of our detection system has been the acquisition of a solid-state Silicon Drift Diode (SDD) detector to replace the solid-state Ge detector to address the heavy load issues. The SDD detector is lightweight compared to the Ge detector. It also has better energy resolution (140 eV) than the Ge detector (180 eV) for the energy range of interest (5-10 KeV), which would reduce the background scattering. Equipped with the newly installed digital x-ray processor (XIA DXP Saturn), the linear count-rate limit has increased 10-fold (from 20 to 250 kilo-count per second), which would reduce the required scan time using the previous setup.. Previous spectrometer arrangements were complex to align and keep aligned with the beam as energy is changes. We have addressed this problem by replacing the previous z-2z scheme by a theta-2 theta arrangement which is much simpler and more effective.