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.
|Monochromator||soft X-ray and FEMTOSPEX|
|Experiment in vacuum||yes|
|Temperature range||30 - 450 K (low-T), 130 - 750 K (variable T)|
|Detector||GaAs Photodiode, gated Avalanche Photodiode (1 ns)|
|Manipulators||Low-Temprerature (He) cryostat, variable temperature cryostat|
|Magnetic field (longitudinal)||.5 Tesla|
|Magnetic field (transverse)||.04 Tesla|