Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 12: Postersitzung (Struktur und Dynamik reiner Oberfl
ächen, Grenzfl
äche fest-flüssig, Nanostrukturen, Teilchen und Cluster, Halbleiteroberfl
ächen und Grenzfl
ächen, Zeitaufgelöste Spektroskopie, Rastersondentechniken, Methodisches)

O 12.60: Poster

Montag, 24. März 2003, 18:00–21:00, P1

A Time-of-Flight Electron Energy Loss Spectrometer — •Bruno Gompf, Christian Peineke, and Martin Dressel — 1.Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart

A major limitation of dispersive sector analyzers used in high resolution electron energy loss spectroscopy (HREELS) is that they are inherently serial devices, leading to long data acquisition times. We developed and constructed a new spectrometer concept, in which the monochromator as well as the analyzer are working with a time-of-flight technique. At electron energies below 10 eV the different time of flight that particles of different energies take to cover a given distance can be used for monochromatization. On the other hand losses in the infrared lead at this electron energies to time differences of several ns, which can be easily detected by a microsphere plate. We will present calculations showing the physical limitations of the concept, which at low electron energies in principal allow an energy resolution better than that of dispersive analyzers. We also show first experimental results and discuss the practical challenges connected with the concept.