RHEA 100 Energy Analyzer for filtering and in-situ Electron Energy Loss Measurements

The RHEA-100 RHEED Energy Analyzer allows in-situ measurements of Electron Energy Loss Spectra (EELS). The energy distribution electrons at different diffracted angles are measured using a highly sensitive photomultiplier and Lock-In technique. Since the energy losses are characteristic of the elemental composition and chemical environment of the surface, fast and sensitive characterizations are now possible during growth.

The RHEA-100 is a high energy, high resolving power energy analyzer with imaging capability (ref. 1/2). It offers modes of operation: In the first mode, complete RHEED diagrams are energy filtered and can be viewed on a fluorescent screen. In the second mode, in-situ energy loss distributions (EELS) for selected angular ranges can measured. The analyzer offers the removal of the inelastically scattered electrons (as it is the case in LEED optics) and the fast, in-situ determination of the chemical state of the surface by EELS. Further, RHEA-100 maintains all specific advantages of the RHEED technique, such as in-situ imaging during growth, long working distances, image acquisition with video-speed, and measurement of intensity oscillations.

Technical Data:

Energy resolution: better than 0.02% of primary energy

Energy range: 15,000 eV; 20,000 eV; or 30,000 eV

Electron detection: large diameter fluorescent screen

Filtered angle: 20 degrees

Data acquisition: * Photomultiplier combined with Lock-In amplifier for EELS measurements

* CCD-Camera for observation of filtered diffraction patterns

Mounting flange: CF 100 standard

Working distance: 50mm to 250mm

Working pressure: up to a few 10^-5 torr