Kernforschungsanlage Julich Gesellschaft MIT Beschrankter Haftung

Forschungszentrum Julich Gmbh

Forschungszentrum Juelich Gmbh

Kernforschungsanlage Julich

Kfa Julich

Harald Ibach

Karl Boden

Udo Linke

Sieghart Lehwald

Heinz-Dieter Bruchmann

Hermann Froitzheim

Josef Frohn

Heinz D Bruchmann

Rene Franchy

Dieter Bruchmann

Sieghard Lehwald

An electrostatic deflector for energy selection of a beam of charged particles has a plurality of main deflector plates arrayed in a generally cylindrical basic shape and to which electrostatic potentials are applied. The main deflector plates are shaped and the potentials are applied to generate a path of said beam from an input side of said deflector to an output side thereof by virtue of a deflecting field which is increasingly weakened to both sides of a central portion of the beam toward the main deflector plates relative to a field of ideal cylindrical shape, thereby causing second order angular aberration of the beam to substantially vanish. A pair of end deflector plates at opposite ends of the cylindrical basic shape have a repulsive potential with respect to the beam to effect focussing of the beam perpendicular to a dispersion plane of the deflector.

Electrostatic deflector with generally cylindrical configuration

A scanning tunnel microscope having an emission tip, specimen holder and xyz movement mechanism as well as devices for applying a voltage between the emission tip and the specimen and for detecting the electrons emanating from the specimen can be used for verifying secondary electrons generated in the same surface region and/or an energy analysis of electrons emitted by the emission tip and scattered by the surface if a cylindrical mirror analyzer with assigned detector is arranged coaxially to the emission tip. With relatively high applied voltages, a cylindrically symmetrical correction electrode between the emission tip and the cylindrical mirror, arranged coaxially to the emission tip, is expedient, with which electrode the imaging properties of the analyzer open toward the specimen are made to approximate those of a conventional cylindrical mirror. A masking device allows a solid angle-oriented detection of scattered and secondary electrons. The outer cylinder of the cylindrical mirror may, at least in part, be made transmissive to photons, which are verified by a detector arranged on the outside. A channel multiplier plate with a fluorescent screen, provided opposite the emissions tip, allows detection of structural and/or emission properties of the emission tip by field ion microscopy or field electron microscopy.

Scanning tunnel microscope capable of detecting electrons emanating from

A crystalline bar is drawn by a zone-melting process or from a melt in a crucible utilizing a magnetic suspension housing, in addition to an axial stabilization magnet, a radial stabilizer surrounding the core and including sensors for the radial position of the core-operating controllers for electromagnets surrounding the core to restore the core to its setpoint position. The fully magnetic suspension of the core eliminates friction while allowing enclosure of the crystal growth compartment to improve the quality of the crystal growth process.

Bar and crucible magnetic suspension for a crystal-growing apparatus

High energy resolution at high electron current at the specimen or at the detector is obtained by an electron beam guiding with focusing energy selection, in particular in an electron spectrometer with emission system and at least one energy dispersive system with different focusing in two mutually perpendicular directions, by a non-circular-symmetrical lens system placed after or before the energy dispersive system and correcting the different focusing of the electrons in the two mutually perpendicular directions such that either the virtual or the real entry stop of the energy dispersive system is imaged on an accessible image plane outside the energy dispersive system or an object outside the energy dispersive system is imaged on the virtual or real exit stop of the latter.

Process for electron beam guiding with energy selection and electron

A complex relative movement in a direction transverse to the crystal draw direction is imparted at the interface between the growing crystal bar and a melt of the crystallizable material by controlled electrical energization of a radial stabilizer acting upon the magnetizable core by which either the bar or the crucible or a supply bar for the material, or both, can be suspended.

Method of and apparatus for growing crystals

An electron energy analyzer in which electrons arriving through an entrance aperture in an energy-dispersive system, are simultaneously analyzed at the exit of the system through a multi-channel detector operating with channel plates. The electron energy analyzer is distinguished through a grid at the exit of the analyzer which is to be brought to the potential of the entrance aperture plate, at the smallest possible spacing from the channel plate or plates, whose mesh size dimension is so small in comparison with the dimension of the electron beam, that no additional structure will be obtained in the registered electron spectrum because of the grid, with a blending grid mask whose blending conforms with the beam dimension and the spacing of the electrodes in the analyzer, and which is brought to a potential with respect to the channel plate, which is adequate for the aspiration of the electrons strayed from the facing channel plate.

Electron energy analyzer with multi-channel detector

The radiant heat of the graphite carrier of a LaB.sub.6 cathode is utilized o heat the input diaphragm of the monochromator of an electron spectrometer by opening up the aperture in the repeller electrode that provides magnetic shielding from the heating current and through which the emitting portion of the cathode projects, so that the entire surface of the graphite carrier can radiate heat towards the input diaphragm. The spacing of the point of the cathode from the graphite carrier may be increased in order to accord with the provision of additional heat in the carrier for radiation to the diaphragm. The radiant heat raises the temperature of the diaphragm and thereby reduces electrostatic charges resulting from bombardment of the diaphragm by electrons from the cathode, allowing a larger beam current to be monochromatized.

Electron-impact spectrometer

A beam guidance for electron beam tests, especially of solid bodies. The ctrons cathodically emitted and electron-optically bundled are subjected at least to an energy selection in a cylinder condenser deflection unit and are subsequently detected or indicated in a detector. The emission and bundling systems are arranged in such a way that the electrons, in the plane at right angles to the cylinder condenser axis, are focused upon the inlet shield or baffle of the condenser, yet are focused at right angles thereto upon the detector. Also disclosed is an electron impact spectrometer having such a beam guidance, and an emission system encompassing a cathode and a lens system for focusing an electron current or flow upon an inlet baffle of a monochromator, with such flow entering into the cylinder condenser monochromator for energy selection of the electrons, which emanate bundled from the monochromator and strike or fall upon the probe or test sample and after reflection thereon come by way of a lens system into the cylinder condenser analyzer and after energy selection and passage through the outlet baffle of the analyzer strike or impinge upon a detector.

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Aachen-Verlautenheide, Germany

Harald Ibach