The neutron decay retardation spectrometer aSPECT: Electromagnetic design and systematic effects F. Glück, S. Baeßler, J. Byrne, M. G. D. van der Grinten, F. J. Hartmann, W. Heil, I. Konorov, G. Petzoldt, Yu. Sobolev and O. Zimmer Eur. Phys. J. A, 23 1 (2005) 135-146 Published online: 23 November 2004 DOI: 10.1140/epja/i2004-10057-1