Neutronic calculations of cold neutron intensity in a He chamber for ultra cold neutron production

摘要

Neutronic optimization studies were performed to get highest cold neutron intensity in a He-II chamber for ultra cold neutron (UCN) production as a UCN source to be installed at a spallation neutron source. Main components of the system studied were Pb-Bi target shield system, graphite reflector, D_2O thermal moderator, D_2 cold moderator and He-II UCN source. Effect of the size of these components on cold neutron intensity and on heat deposition was studied under the condition of 600MeV proton energy and 20muA proton current. It was found that in the limitation of 1 W heat removal of the He cryostat we would obtain a cold neutron average flux of 7x10~11 (n/cm~2/sec) in the He chamber.