The flux of cold neutrons that is obtainable from various high energy netron sources is studied for a particular model of
a cold neutron source when the cold moderation region of the apparatus is at 20, 70, and 298K. The maximum flux obtained with
a californium-252 source was 2.7·10−3 cold neutron per (cm2·second (source neutron)). This flux was obtained when the cold moderation region of the apparatus was at 20K and when the
thermal moderator is either polyethylene or trimethylbenzene and the cold moderator is polyethylene. This flux should allow
sensitive prompt and delayed neutron activation analysis measurements.