PEEM End Station

 The PhotoEmission Electron Microscope (PEEM) principally consists of electron optics for performing spatially resolved spectroscopy and topography on samples, manipulated within a ultrahigh vacuum (UHV) environment.

The beamline combines high spatial resolution with high flux density to resolve nanostructures on nanometer length scales. Through the PEEM, the Nanoscience beamline is able to resolve nanoparticles with diameters of less than 20nm, using polarized soft x-rays. The PEEM has been designed and built in such a way that future upgrades to improve the spatial resolution can be added as technology develops.

In addition to the PEEM, the instrument also has a high stability electron gun in order to perform Low-Energy Electron Microscopy (LEEM). The LEEM consists of an electron gun which illuminates the sample with a monochromatic beam of electrons of tuneable energy and diameter.

State of the art sample preparation facility is available which includes LEED, Auger and STM.

The PEEM enclosure on I06.

The specifications of the PEEM are meant as guidelines for ideal experimental conditions. These conditions can be summarized as: good sample conductivity, clean surface and atomically flat, high contrast and stability. Achievement of high-resolution requires a lot of effort and has to be discussed with the beamline staff.

The fields of view may vary between 80 and 2 mm. For XPEEM and LEEM, the largest field of view is limited by the size of the illumination source of 10 mm (x-rays) and 50 mm (LEEM), respectively.

EVAPORATION SOURCES

One evaporation source is available in the main chamber and two in the preparation chamber. EFM 3 evaporators are currently fitted. For available evaporants and crucibles, please discuss your needs with the beamline staff. The access to the chambers is through a DN40 flange with an inner bore diameter is 38 mm. For the distances to the sample, please contact the beamline staff.

Evaporation of most metallic compounds is allowed (Au, Ag, Co, Cu, Fe, ...). Volatile metals are NOT allowed. Details must be discussed with beamline staff before experiment starts.

Dosing of gasses is possible and has to be agreed with the beamline staff well in advance of the experiment starting.

Evaporation of volatile organic molecules is not permitted in the PEEM or the PEEM Preparation Chamber.

PREPARATION CHAMBER

The preparation chamber is equipped with LEED, AES, VT-STM, two EFM3 evaporators, thickness monitor, gas dosing, sample annealing and sputtering.

The transfer of the sample is done through a load-lock system and the complete transfer from air to measuring position in PEEM takes approximately 15 minutes. 

Photo of PEEM, preparation chamber and load-lock.