FEMTOSPEX-Magnetism

Femto-Second-Pump-Probe

Experimental station for fs time resolved XMCD and XAS

The FEMTOSPEX XMCD/XAS experimental station was set up in 2004 for the proof-of-principle Femtoslicing experiments and has since then been a workhorse for both in-house research and user operation at the HZB. It has been built particularly for time-resolved XAS and XMCD measurements in transmission, coping with the reduced photon flux in fs time resolved experiments. The main scientific focus is on ultrafast magnetization dynamics and time-resolved X-ray absorption spectroscopy.

The experimental setup for laser pump – X-ray probe on magnetic samples consists of a measurement chamber housing the magnet and transmission sample, and the detector chamber with a fast avalanche photodiode (APD). Laser and X-ray beams enter through the beamline flange under an angle of 1.5° (almost collinear). An Al foil mounted between the chambers prevents laser light to enter the detection chamber with the APD.

Layout of the fs XMCD/XAS chamber

Layout of the fs XMCD/XAS chamber

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Station data
Temperature range 30 - 450 K (low-T), 130 - 750 K (variable T)
Pressure Range <= 10E-7 mbar
Detector GaAs Photodiode, gated Avalanche Photodiode (1 ns)
Manipulators Low-Temprerature (He) cryostat, variable temperature cryostat
Sample holder compatibility Omicron or compatible
Beamline(s)

UE112_PGM-1, UE56-2_PGM-2, UE56-2_PGM-1, UE56-1_ZPM, UE56-1_PGM, UE52_SGM, U49-2_PGM-1, PM3

Magnetic field (longitudinal) .5 Tesla
Magnetic field (transverse) .04 Tesla

Methods

NEXAFS, XMCD, XMLD, Time-resolved studies