title: Proton induced quasi-monochromatic x-ray beams for soft x-ray spectroscopy studies and selective x-ray fluorescence analysis.
abstract: We present the analytical features and performance of an x-ray spectroscopy end station of moderate energy resolution operating with proton-induced quasi-monochromatic x-ray beams. The apparatus was designed, installed and operated at the 5.5 MV Tandem VdG Accelerator Laboratory of the Institute of Nuclear Physics, N.C.S.R. "Demokritos," Athens. The setup includes a two-level ultrahigh vacuum chamber that hosts in the lower level up to six primary targets in a rotatable holder; there, the irradiation of pure element materials-used as primary targets-with few-MeV high current (~μA) proton beams produces intense quasi-monochromatic x-ray beams of selectable energy. In the chamber's upper level, a six-position rotatable sample holder hosts the targets considered for x-ray spectroscopy studies. The proton-induced x-ray beam, after proper collimation, is guided to the sample position whereas various filters can be also inserted along the beam's path to eliminate the backscattered protons or/and to absorb selectively components of the x-ray beam. The apparatus incorporates an ultrathin window Si(Li) spectrometer (FWHM 136 eV at 5.89 keV) coupled with low-noise electronics capable of efficiently detecting photons down to carbon Kα. Exemplary soft x-ray spectroscopy studies and results of selective x-ray fluorescence analysis are presented.
authors.affiliation: Institute of Nuclear Physics, N.C.S.R. Demokritos, Aghia Paraskevi, 15310 Athens, Greece. dsokaras@slac.stanford.edu
authors.forename: D
authors.initials: D
authors.lastname: Sokaras
authors.forename: Ch
authors.initials: Ch
authors.lastname: Zarkadas
authors.forename: R
authors.initials: R
authors.lastname: Fliegauf
authors.forename: B
authors.initials: B
authors.lastname: Beckhoff
authors.forename: A G
authors.initials: AG
authors.lastname: Karydas