Intensity enhancement of cold neutrons from a coupled liquid-hydrogen moderator for pulsed cold neutron sources

In order to obtain higher cold neutron intensity from a coupled liquid-hydr ogen moderator with a premoderator for pulsed cold neutron sources, we exam ined a partial enhancement method, namely, narrow beam extraction for both a flat liquid-hydrogen moderator and a single-groove one. Combined with the narrow beam extraction, which is especially suitable for small-angle scatt ering and neutron reflectometry experiments, a single-groove moderator prov ides higher intensity, by about 30%, than a flat-surface moderator at the r egion of interest on a viewed surface. The effect of double-side beam extra ction from such moderators on the intensity gain factor is also discussed. (C) 1999 Elsevier Science B.V. All rights reserved.