Combined cold and thermal neutron moderator

Abstract

The invention relates to a combined cold and thermal neutron moderator (10) having a longitudinal axis (t) and at least one neutron exit window (50) at a first end (11, 12), and a cold moderator (20) arranged along the longitudinal axis (t), a thermal pre-moderator (30) and a vacuum space (40), said thermal pre-moderator (30) having a pre-moderator mantle (32) surrounding the cold moderator (20) along the longitudinal axis (t) and separated from the cold moderator (20) by the vacuum space (40), characterized in that the pre-moderator (30) comprises a pre¬moderator collar (34) extending at least at the first end (11, 12) from the pre¬moderator jacket (32) towards the longitudinal axis (t), which substantially covers the portion of the vacuum space (40) between the cold moderator (20) and the pre¬moderator mantle (32) from the direction of the neutron exit window (50), leaving substantially free at least one end (21, 22) of the cold moderator (20) at the end (11, 12). WO

Dependencies are inferred from the claim text.