| 摘要 |
Method and apparatus for minimizing signal noise (20, 22) in thermal, epithermal, and cold neutron fluorescence processes using neutron flux modulation and gamma ray detector pulse gating synchronized to neutron time of flight (NTOF). The apparatus includes a source (12) of thermal, epithermal, and/or cold neutrons, optionally switched between flux or power settings in various embodiments, a gamma ray detector (14) or detection system capable of either being turned ON and OFF, in some embodiments, or else being told to regard or disregard gamma ray signals (20, 22) in other embodiments, a control mechanism (24), and either a target range detector (26) or a prior measurement of target range, in embodiments where the range remains fixed. The gamma ray detector (14) is synchronized to the NTOF by the control mechanism (24) so that it remains switched OFF during the pulse period of the neutron source (12) and for the subsequent NTOF so that any nuisance signals (20, 22) arriving at the detector (14) during these times are not detected or considered. |
