Electron spectroscopy laboratory hosts materials research infrastructure for studying the electronic properties and interactions from atomic and molecular vapors to free unsupported nanostructures as well as condenced phase of matter. Most of the equipment is custom engineered and manufactured and/or tailored to provide best accuracy possible for users in Oulu laboratory and in international radiation source facilities. With instruments in Oulu, ELSP group can perform test measurements and experiment development before entering a beamtime at synchrotron radiation facilities. A crucial function of the laboratory in Oulu is also to train the masters and PhD students to the experimental work.

Experimental setups

Electron and ion spectrometers

Group has two hemispherical electron analyzers SES-100 and SES-200 manufactured by VG Scienta.  Spectrometers can separate and measure electrons with different kinetic energies (surface science instruments).

• SES-200: In permanent use in Oulu-lab. High resolution (1 meV) electron spectroscopy equipped with a position sensitive detector for electron and photon induced electron spectroscopy and electron energy loss experiments.

• SES-100: More compact than SES-200, can be used in multiple research sites, resolution up to 3 meV.

• Time-of-Flight (TOF) mass spectrometer (Wiley-McLaren-type): 30 cm vacuum drift tube, Microchannel plate detector, mass resolution < 1 amu.

• Coincidence set-up (SES-100 + TOF): TOF is used in combination with the SES-100 in order to perform electron-ion coincidence (PEPICO) and electron-ion-ion coincidence (PIPICO) experiments.
• X-Ray Photoemission Electron Microscopy (XPEEM)

Laboratory Excitation Sources

• Specs UVS 300 source: He I radiation (21.2 eV) for studies of valence photoelectron spectra of various samples.

• X-ray tube: Equipped with Al and Mg anodes.
• Electrongun

Exchange Metal Cluster Source (EXMEC)

Capable of producing of free, neutral and size varied metal-, semiconductor- and molecular nanoclusters in the size range from few tens to thousands of atoms/cluster. For more informatio, see here.

Fluorescence spectrometer

Andor SR-500 spectrograph can be used to measure emitted light from de-excitation of atoms and molecules for wavelenghts between 300-1200 nm with < 0.1nm resolution. With the aid of extended fiber optic cables one can do measurements even in industrial/harsh conditions with easily transportable setup.

Vapor sources

For producing vapors from solid samples one needs an oven. The group has long traditions in manufacturing and designing different types of ovens for vapor production and currently two types of ovens are used in the experiments:

• Resistively heated ovens: For low- and intermediate temperature ranges.
• Inductively heated ovens: For high temperature metals and semimetals.

The existing multistage ovens enable also the dissosiative preparation of multimers and/or single molecules prior to probing their properties. The newly developed simultaneous solid state & vapor phase oven design provides new insight into the calibration of the absolute binding energies in solid state.

Electron impact spectroscopy

In order to create deep core-hole states and to follow their Auger decay and various cascade processes, also charged particles, such as electrons, have been used for primary ionization. The spectra created by electron impact have been recorded with the SES-200 electron energy analyzer in the Oulu laboratory.

Electron energy loss spectroscopy (EELS)

Detecting the elastically and inelastically scattered electrons from primary electron beam and recording the energy loss of the electrons can be used as a tool for studying both valence and core excitations of the target. The EELS method can be used as an analogue to the photon absorption experiments or, under certain conditions (large scattering angles, low energy), and for studying dipole- and spin-forbidden transitions. For EELS experiments a special setup has been designed in Oulu, where the Scienta SES-100 analyzer is used in a reversed mode as an electron energy monochromator and the SES-200 as an electron energy analyzer.

Electron optical calculations for further development of the electron spectrometers, EELS systems and ion time-of-flight analyzers are also an important part of research in Oulu.