CRYOGENIC SYSTEM OF THE SWISS ULTRA-COLD NEUTRON SOURCE

The ultra cold neutron source under construction at the Paul Scherrer Institute is a new facility dedicated to the production of UCN. An essential element of this source is a 5 K solid ortho-deuterium moderator. The cryogenic system of the UCN source is presented emphasizing on the thermal process, design criteria, and evaluation of heat loads in the D2 condenser, para-ortho D2 converter and moderator.