Editing Neutron (section)

=== Other uses ===

[[Neutron temperature|''Cold'', ''thermal'', and ''hot'']] [[neutron radiation]] is commonly employed in [[neutron scattering]] facilities for [[neutron diffraction]], [[small-angle neutron scattering]], and [[neutron reflectometry]]. Slow neutron [[matter waves]] exhibit properties similar to geometrical and wave optics of light, including reflection, refraction, diffraction, and interference.<ref name="Klein Werner 1983 pp. 259–335">{{cite journal | last1=Klein | first1=A G | last2=Werner | first2=S A | title=Neutron optics | journal=Reports on Progress in Physics | publisher=IOP Publishing | volume=46 | issue=3 | date=1983-03-01 | issn=0034-4885 | doi=10.1088/0034-4885/46/3/001 | pages=259–335 | s2cid=250903152 | url=https://www.researchgate.net/publication/231072989 | access-date=2023-07-06 | archive-date=2024-05-12 | archive-url=https://web.archive.org/web/20240512232101/https://www.researchgate.net/publication/231072989_4_Neutron_Optics | url-status=live }}</ref> Neutrons are complementary to [[X-ray]]s in terms of atomic contrasts by different scattering [[cross section (physics)|cross sections]]; sensitivity to magnetism; energy range for inelastic neutron spectroscopy; and deep penetration into matter.

The development of "neutron lenses" based on total internal reflection within hollow glass capillary tubes or by reflection from dimpled aluminum plates has driven ongoing research into neutron microscopy and neutron/[[gamma ray tomography]].<ref>{{cite journal |last=Kumakhov |first=M.A. |author2=Sharov, V.A. |year=1992 |title=A neutron lens |journal=[[Nature (journal)|Nature]] |volume=357 |issue= 6377|pages=390–391 |doi=10.1038/357390a0 |bibcode= 1992Natur.357..390K|s2cid=37062511 }}</ref><ref>[http://www.physorg.com/news599.html Physorg.com, "New Way of 'Seeing': A 'Neutron Microscope'"] {{Webarchive|url=https://web.archive.org/web/20120124122838/http://www.physorg.com/news599.html |date=2012-01-24 }}. Physorg.com (2004-07-30). Retrieved on 2012-08-16.</ref><ref>[http://www.nasa.gov/vision/earth/technologies/nuggets.html "NASA Develops a Nugget to Search for Life in Space"] {{Webarchive|url=https://web.archive.org/web/20140308200231/http://www.nasa.gov/vision/earth/technologies/nuggets.html |date=2014-03-08 }}. NASA.gov (2007-11-30). Retrieved on 2012-08-16.</ref><ref>{{Cite journal|last1=Ioffe|first1=A.|last2=Dabagov|first2=S.|last3=Kumakhov|first3=M.|date=1995-01-01|title=Effective neutron bending at large angles|url=https://doi.org/10.1080/10448639508217696|journal=Neutron News|volume=6|issue=3|pages=20–21|doi=10.1080/10448639508217696|issn=1044-8632}}</ref>

A major use of neutrons is to excite delayed and prompt [[gamma ray]]s from elements in materials. This forms the basis of [[neutron activation analysis]] (NAA) and [[prompt gamma neutron activation analysis]] (PGNAA). NAA is most often used to analyze small samples of materials in a [[nuclear reactor]] whilst PGNAA is most often used to analyze subterranean rocks around [[bore hole]]s and industrial bulk materials on conveyor belts.

Another use of neutron emitters is the detection of light nuclei, in particular the hydrogen found in water molecules. When a fast neutron collides with a light nucleus, it loses a large fraction of its energy. By measuring the rate at which slow neutrons return to the probe after reflecting off of hydrogen nuclei, a [[neutron probe]] may determine the water content in soil.