Ion Trap /UE52_PGM

The Ion trap instrument is located downstream from the focus of the UE52_PGM beamline and due to the low divergence of the x-ray beam, ideal conditions for the effective irradiation of the ion cloud in the Ion trap station are achieved. The UE52_PGM is an undulator beamline with a plane-grating monochromator delivering soft X-ray radiation with variable polarization.

The Ion Trap instrument is designed for x-ray magnetic circular dichroism (XMCD) spectroscopy of cold gaseous ions in a magnetic field of up to 5 T. Size-selected cluster ions, molecular ions, and ionic complexes can be studied using a unique cryogenic linear quadrupole ion trap with 5 T superconducting solenoid. The radio-frequency ion trap is operated in the space-charge limit for high signal-to-noise ratio. Magnetron sputtering and gas aggregation is the standard ion source, but other ion sources can be added as well.

Selected Applications:

• Magnetic moment characterization of free molecular ions
• Controlled radiation damage in organic ions via photofragmentation
• Electron correlation in highly excited states of simple molecules

schematic view of the experimental setup

Methods

XMCD, Mass Spectrometry, NEXAFS

Remote access

not possible

view of the experimental setup installed at UE52-PGM

Because of its complexity, this experimental setup requires thorough consultation with the scientists in charge. Please contact the instrument scientists well ahead of time to discuss experimental feasibility. This is currently the only instrument world-wide that allows performing XMCD studies of cold gas-phase ions.

Experimental capabilities:

• metal ion source (single/dual target magnetron sputtering and gas aggregation with additional reactive gas port)
• hexapole collision/reaction cell for preparation of ionic complexes and oxides
• quadrupole mass filter for monodisperse ion beams
• cryogenic ion trap (liquid-helium-cooled) with ion temperatures down to 7.4 K
• buffer gas cooling for Zeeman relaxation
• applied homogeneous magnetic field (0 - 5 T) coaxial with ion trap axis
• reflectron time-of-flight mass spectrometer for partial ion yield detection of x-ray absorption and XMCD spectra

Further ion sources (e.g. electrospray ionization) can be made available upon request.

Operated by

Ion Trap is jointly developed and operated by Helmholtz-Zentrum Berlin, Universität Freiburg, TU Berlin, Kyushu University, and Toyota Technological Institute.