Kratos Analytical Limited

Simon C Page

Andrew R Walker

Colin Duncan Park

Christopher Michael Hopper

The present invention provides an electron spectroscopy apparatus () comprising a high energy particle source () for irradiating a sample, an electron detector system () (e.g. including a delay line detector) for detecting electrons emitted from the sample and an ion gun () for delivering a polycyclic aromatic hydrocarbon (PAH) ion beam to the sample, wherein the ion gun comprises a polycyclic aromatic hydrocarbon ion source, for example comprising coronene. In an embodiment, the PAH is located in a heated chamber () and vaporised to produce gas phase PAH. The gas phase PAH molecules are then ionised by electron impact, extracted from the ion source via an extraction field and focussed using ion optics. The PAH ion beam can be used for surface cleaning and depth analysis.

Electron spectroscopy

A charged particle (e.g. photoelectron) spectrometer is operable in a first mode to produce an energy spectrum relating to the composition of a sample being analysed, and in a second mode to produce a charged particle image of the surface of the sample being analysed. A detector is used to detect charged particles produced in both modes of operation. A method of operation of the spectrometer includes the step of selecting which of said first and second modes to use and the detector being operated accordingly.

Charged particle spectrometer and detector therefor

A charged particle energy analyser has a magnetic lens such as a snorkel-type lens and a source for directing ionising radiation onto a specimen causing charged particles to be emitted from its surface. The specimen is immersed in the magnetic imaging field of the magnetic lens so that particles having energies in a predetermined energy range are brought to a focus, the energies of the focussed particles being analysed by an energy analyser. An electrode arrangement is provided for enabling the magnetic imaging field of the magnetic lens to utilise unfocussed particles to cause charge neutralisation of the specimen. Alternatively, charged particles from a source are subjected to an electric field which is transverse to the optical axis of the magnetic lens and are guided onto the specimen by the magnetic imaging field of the magnetic lens.

Charged particle energy analyzers

A charged particle energy analyzer includes two hemispherical electrodes and means for developing an inverse square electric field in the gap between the two electrodes. An afocal charged particle lens arrangement is arranged to project a charged particle image of a sample into the electric field. Two baffles are disposed in the gap between the electrodes the baffles being effective to restrict the energy and angular divergence of the particles transmitted by the analyzer, the baffles being positioned so as to reduce the dependence of the energy and the orientation of the charged particles transmitted by the baffles on the position of the particles within the image. A two-dimensional detector is arranged to detect the charged particle image transmitted by the analyzer.

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Hadfield, United Kingdom

Simon C Page