Hannover 2010 – scientific programme

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A: Fachverband Atomphysik

A 8: Poster I

A 8.4: Poster

Tuesday, March 9, 2010, 16:30–19:00, Lichthof

Resolution enhancement in the magnetic bottle photoelectron spectrometer (PES) by means of a time-variable potential step — •Moritz Weigt and Bernd von Issendorff — Universität Freiburg

We present a new method for improving the resolution of a magnetic bottle photoelectron spectrometer. This is achieved by a time-variable potential step which the electrons cross after a certain part of their flightpath.

Normally, a number of effects lead to electrons of the same velocity and emission time being distributed in a packet of finite length. This leads to a distribution of arrival times at the detector, limiting the precision of the time-of-flight measurement.

The time-variable potential time-focuses these electron packets in the detector plane, in principle eliminating this measurement error. It can be shown that this correction is equally valid for all electron energies, in contrast to other methods using pulsed fields for resolution enhancement.

A PES using the new method is currently under construction and, according to detailed simulations, could achieve an energy resolution of at least 1/300 for electron energies between 0.25 and 10 eV. This would mean an improvement by a factor of 5 to 10 compared to the existing setup.