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| | Neutron Vision |
 | | Passing neutrons through a pinhole creates a tightly collimated beam, while refraction from a suitable crystal--separating wavelengths a bit like a prism--can yield neutrons of a single energy or wavelength. |
 | | Neutrons from a 2-centimeter-wide beam first hit a coarse grating, which creates a series of bright neutron "lines." Each neutron line acts independently as a single "coherent" source of waves, like light from a pinhole used in classic optics experiments, because the slits are widely spaced (several millimeters apart). |
 | | Neutron refraction can cleanly distinguish between, say, titanium and molybdenum, even though their absorption of neutrons is similar. |
| focus.aps.org /story/v17/st20 (687 words) |
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