Open main menu
Home
Random
Recent changes
Special pages
Community portal
Preferences
About Wikipedia
Disclaimers
Incubator escapee wiki
Search
User menu
Talk
Dark mode
Contributions
Create account
Log in
Editing
Neutron
(section)
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
== Detection == {{Main|Neutron detection}} The common means of detecting a [[electric charge|charged]] [[elementary particle|particle]] by looking for a track of ionization (such as in a [[cloud chamber]]) does not work for neutrons directly. Neutrons that elastically scatter off atoms can create an ionization track that is detectable, but the experiments are not as simple to carry out; other means for detecting neutrons, consisting of allowing them to interact with atomic nuclei, are more commonly used. The commonly used methods to detect neutrons can therefore be categorized according to the nuclear processes relied upon, mainly [[neutron capture]] or [[elastic scattering]].<ref>{{cite book|chapter=Ch. 14|title=Radiation Detection and Measurement|author=Knoll, Glenn F.|publisher=John Wiley & Sons|year=1979|isbn=978-0471495451|chapter-url=https://archive.org/details/radiationdetecti00knol_0}}</ref> === Neutron detection by neutron capture === A common method for detecting neutrons involves converting the energy released from [[neutron capture]] reactions into electrical signals. Certain nuclides have a high neutron capture [[cross section (physics)|cross section]], which is the probability of absorbing a neutron. Upon neutron capture, the compound nucleus emits more easily detectable radiation, for example an alpha particle, which is then detected. The nuclides {{SimpleNuclide|Helium|3}}, {{SimpleNuclide|Lithium|6}}, {{SimpleNuclide|Boron|10}}, {{SimpleNuclide|Uranium|233}}, {{SimpleNuclide|Uranium|235}}, {{SimpleNuclide|Neptunium|237}}, and {{SimpleNuclide|Plutonium|239}} are useful for this purpose. <!-- The following needs correction, errors due to lack of reference: These nuclides are rarely found in nature, but can be accumulated through processes such as isotopic enrichment. The cross section for the process of neutron capture is much lower at high energies than at low energies. Therefore, the detection of neutrons by neutron capture requires a preceding slowing down of neutrons. For this purpose, a [[neutron moderator]] is used, typically a thick slab of polyethylene. Neutron detectors using the moderate-and-capture approach cannot measure neutron energy, precise time of arrival, or direction of incidence, because this information is lost during moderation. --> === Neutron detection by elastic scattering === Neutrons can elastically scatter off nuclei, causing the struck nucleus to recoil. Kinematically, a neutron can transfer more energy to a light nucleus such as hydrogen or helium than to a heavier nucleus. Detectors relying on elastic scattering are called fast neutron detectors. Recoiling nuclei can ionize and excite further atoms through collisions. Charge and/or scintillation light produced in this way can be collected to produce a detected signal. A major challenge in fast neutron detection is discerning such signals from erroneous signals produced by gamma radiation in the same detector. Methods such as pulse shape discrimination can be used in distinguishing neutron signals from gamma-ray signals, although certain inorganic scintillator-based detectors have been developed <ref>{{Cite journal |last = Ghosh |first = P. |author2 = W. Fu |author3 = M. J. Harrison |author4 = P. K. Doyle |author5 = N. S. Edwards |author6 = J. A. Roberts |author7 = D. S. McGregor |year = 2018 |title = A high-efficiency, low-ฤerenkov Micro-Layered Fast-Neutron Detector for the TREAT hodoscope |journal = Nuclear Instruments and Methods in Physics Research Section A |volume = 904 |pages = 100โ106 |doi = 10.1016/j.nima.2018.07.035 |bibcode = 2018NIMPA.904..100G |s2cid = 126130994 |doi-access = free }}</ref><ref>{{Cite book |last = Ghosh |first = P. |author2= D. M. Nichols |author3= W. Fu |author4 = J. A. Roberts |author5 = D. S. McGregor |title = 2019 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) |chapter = Gamma-Ray Rejection of the SiPM-coupled Micro-Layered Fast-Neutron Detector |year = 2019 |pages= 1โ3 |doi= 10.1109/NSS/MIC42101.2019.9059869|isbn = 978-1-7281-4164-0 |s2cid = 204877955 }}</ref> to selectively detect neutrons in mixed radiation fields inherently without any additional techniques. Fast neutron detectors have the advantage of not requiring a moderator, and are therefore capable of measuring the neutron's energy, time of arrival, and in certain cases direction of incidence.
Edit summary
(Briefly describe your changes)
By publishing changes, you agree to the
Terms of Use
, and you irrevocably agree to release your contribution under the
CC BY-SA 4.0 License
and the
GFDL
. You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
Cancel
Editing help
(opens in new window)