Low Dose Photoelectron Spectroscopy at PM4


NEXAFS, Time-resolved studies, XPS, UPS, ARPES

Beamline data
Energy range 20 - 2000 eV
Energy resolution 6,000 at 400 eV
Flux 1e9 - 1e10 phot/s
Polarisation horizontal
Focus size (hor. x vert.) 0.3 x 0.09
Phone 14713
More details PM4
Station data
Temperature range 10-500K
Pressure Range For details contact the scientist in charge.
Detector Scienta ArTOF-10k electron energy analyzer (the Scienta SES-100 spectrometer is currently out-of-order)
Manipulators x,y,z,θ stage with Janis cryostat
Sample holder compatibility flag (a.k.a Omicron)-style
Remote Access
Sample maximum size 10mm x 10mm
Top preparation chamber clean sample preparation - MCP LEED, mass spectrometer, many free ports
Side prep. chamber (clean) preparation chamber for non-organic samples - several ports for replaceable evaporators etc, gas inlet, quartz microbalance, sputter gun, resistive heating up to 900 K, mass spectrometer, storage place for 5 samples (1 heatable, 4 not-heatable)
Side prep. chamber (organics) preparation chamber for organic samples - several ports for replaceable evaporators etc, storage place for 6 samples

The LowDose PES end-station is permanently installed at the PM4 dipole beamline. 

It is equipped with a SES100 hemispherical analyzer, as well as with a novel angle-resolved time-of-flight (ArTOF) spectrometer. 

Distinctive features of the latter are an extremely high transmission and the possibility to collect electrons over a very broad angular range in parallel. 

Thanks to the high transmission of the ArTOF, roughly 1000 times faster acquisition times and equally reduced dose rates can be achieved with respect to the more conventional hemispherical analyzers, thus making possible PES investigations of materials that usually suffer from radiation damage. 

When further considering its full cone detection capabilities, the ArTOF turns out to be particularly suitable to track changes in the sample electronic structure as a function of parameters such as gas exposure, temperature or delay after excitation from an optical pump. 

As the ArTOF calls for a pulsed source with repetition rate of few MHz maximum, a fast mechanical chopper is installed at the intermediate focus of the beamline enabling permanent access to 1.25 MHz - spaced X-ray bunches, not only with the single-bunch filling pattern of the storage ring, but also during the more common hybrid operation mode.

The end-station has access to a synchronized ultra-fast (300 fs) high-average power (30 W) high- repetition rate (up to 2MHz) infrared (1030 nm) laser (and its second to fourth harmonics) for time-resolved laser-pump/ x-ray-probe photoemission measurements.