METIS Time-of-Flight Momentum Microscope by SPECS
Announcement posted by John Morris Group 03 May 2016
John Morris Scientific is proud to announce the METIS, a new momentum microscope developed as a collaboration between SPECS and Surface Concept. Metis is a so called Time-of-Flight (ToF) PEEM that allows image electrons to emit from a surface with lateral resolution (optical imaging) together with energy and angular dispersive measurements (ARPES). A tool for combined microscopic and spectroscopic measurements, it allows for instant collection of photoelectron spectra in the same location as seen in microscopy mode.
The newly developed and patented lens system can focus emitted electrons either with respect to the point of their lateral origin (imaging or gauss mode) or with respect to the emitted angle (momentum or PES mode). Real-space as well as k-space Imaging is possible with this machine, via on-the-fly switching. The energy dispersive element, which produces the energy spectrum for PES measurements, is the drift tube of the ToF detector section. A delay line detector collects the electrons and detects their arrival time to produce a three dimensional dataset of stacked 2D constant energy maps. The ToF design requires a pulsed light source such as a laser or a synchrotron (in special operation mode).
The new lens system makes a typical manipulator obsolete since the lens can collect the complete hemisphere of ejected electrons (+/- 90° in x and y). The manipulator is replaced by a hexapod for the fine adjustment and orientation of the sample in the experiment. In contrast to classical ARPES measurements, a motorised degree of freedom for systematic measurements is, hence, no longer required. This allows an extremely compact design for easy inclusion into existing SPECS FlexMod based and custom designed experiments.
The key advantage of the METIS is the fact that measurements may be taken with high transmission, e.g. with very high intensity on a short time scale. Proving practical for experiments with very short acquisition times, such as sensitive samples (e.g. reactive surfaces or organic layers).
Metis is principally designed for scientists accessing pulsed light sources and with a focus on electronic band structures; materials science, classical solid state physics and physical chemistry demanding high scientific throughput and large information depth (multidimensional measurements in energy and momentum space) on local structures on their surface will benefit from this combined spectro-microscopy tool.