Production of ultracold neutrons from cryogenic 2H2, O2, and C2H4 converters F. Atchison, B. Blau, K. Bodek, B. van den Brandt, T. Bryś, M. Daum, P. Fierlinger, P. Geltenbort, P. Hautle, R. Henneck et al. (17 more) EPL, 95 1 (2011) 12001 Published online: 14 June 2011 DOI: 10.1209/0295-5075/95/12001