| 摘要 |
Apparatus and methods for forming thermal, epithermal, and/or cold neutrons into a beam using momentum transfer. The apparatus includes a source of thermal, epithermal, or cold neutrons, a momentum transfer mechanism containing a collection of suitable atoms that collide elastically with the neutrons, and an apparatus for moving the momentum transfer medium in a preferred direction. The embodiments include locating the neutron source within the test section of a wind tunnel filled with a gas consisting of appropriate atoms, either supersonic, transonic, or subsonic, locating the neutron source in the midst of multiple rotors constructed of appropriate atoms, and locating the neutron source inside a tube constructed of appropriate atoms, where the tube is excited by a mechanical transducer to a bulk acoustic wave, while the neutron source is optionally switched off and on to cause neutrons to enter the tube walls only when the tube walls are moving in the preferred direction. |
