The method of direct neutrino mass determination based on the kinematics of tritium beta decay, which is adopted by the KATRIN experiment, makes use of a large, high-resolution electrostatic spectrometer with magnetic adiabatic collimation. In order to target a sensitivity on the neutrino mass of 0.2 eV/c^2, a detailed understanding of the electromagnetic properties of the electron spectrometer is essential, requiring comprehensive calibration measurements with dedicated electron sources. In this paper we report on a prototype of a photoelectron source providing a narrow energy spread and angular selectivity. Both are key properties for the characterisation of the spectrometer. The angular selectivity is achieved by applying non-parallel strong electric and magnetic fields: Directly after being created, photoelectrons are accelerated rapidly and non-adiabatically by a strong electric field before adiabatic magnetic guiding takes over.
@article{arxiv.1011.6365,
title = {Prototype of an angular-selective photoelectron calibration source for the KATRIN experiment},
author = {K. Valerius and H. Hein and H. Baumeister and M. Beck and K. Bokeloh and J. Bonn and F. Glück and H. -W. Ortjohann and B. Ostrick and M. Zbořil and Ch. Weinheimer},
journal= {arXiv preprint arXiv:1011.6365},
year = {2011}
}