Understanding of ultra-cold–neutron production in solid deuterium A. Frei, E. Gutsmiedl, C. Morkel, A. R. Müller, S. Paul, S. Rols, H. Schober and T. Unruh EPL, 92 6 (2010) 62001 Published online: 20 January 2011 DOI: 10.1209/0295-5075/92/62001