Neutron optics of the PSI ultracold-neutron source: characterization and simulation G. Bison, B. Blau, M. Daum, L. Göltl, R. Henneck, K. Kirch, B. Lauss, D. Ries, P. Schmidt-Wellenburg and G. Zsigmond Eur. Phys. J. A, 56 2 (2020) 33 Published online: 04 February 2020 DOI: 10.1140/epja/s10050-020-00027-w