Inverse beta decay: Difference between revisions
Content deleted Content added
m Removed elaboration of SAGE acronym. |
short description, links #article-section-source-editor Tags: Mobile edit Mobile app edit iOS app edit |
||
| (29 intermediate revisions by 23 users not shown) | |||
| Line 1: | Line 1: | ||
{{short description|Nuclear reaction between an electron antineutrino and proton}} |
|||
| ⚫ | ''' |
||
{{about|capture of an antineutrino|capture of an electron|electron capture}} |
|||
| ⚫ | In [[Nuclear physics|nuclear]] and [[particle physics]], '''inverse beta decay''', commonly abbreviated to '''IBD''',<ref>{{Cite journal|last1 = Daya Bay Collaboration|last2 = An|first2 = F. P.|last3 = Balantekin|first3 = A. B.|last4 = Band|first4 = H. R.|last5 = Bishai|first5 = M.|last6 = Blyth|first6 = S.|last7 = Butorov|first7 = I.|last8 = Cao|first8 = D.|last9 = Cao|first9 = G. F.|date = 2016-02-12|title = Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay|journal = Physical Review Letters|volume = 116|issue = 6|pages = 061801|doi = 10.1103/PhysRevLett.116.061801|pmid=26918980|bibcode = 2016PhRvL.116f1801A|arxiv = 1508.04233|s2cid = 8567768}}</ref> is a [[nuclear reaction]] involving an [[electron antineutrino]] scattering off a [[proton]], creating a [[positron]] and a [[neutron]]. This process is commonly used in the detection of electron antineutrinos in [[neutrino detector]]s, such as the first detection of antineutrinos in the [[Cowan–Reines neutrino experiment]], or in neutrino experiments such as [[Kamioka Liquid Scintillator Antineutrino Detector|KamLAND]] and [[Borexino]]. It is an essential process to experiments involving low-energy neutrinos (< 60 [[MeV]])<ref name=":0">{{Cite journal|last1=Vogel|first1=P.|last2=Beacom|first2=J. F.|date=1999-07-27|title=Angular distribution of neutron inverse beta decay|journal=Physical Review D|volume=60|issue=5|pages=053003|doi=10.1103/PhysRevD.60.053003|arxiv=hep-ph/9903554|bibcode=1999PhRvD..60e3003V}}</ref> such as those studying [[neutrino oscillation]],<ref name=":0" /> [[Neutrino#Reactor neutrinos|reactor neutrinos]], [[sterile neutrino]]s, and [[Geoneutrino|geoneutrinos.]]<ref name=":1">{{Cite journal|last1 = Oralbaev|first1 = A.|last2 = Skorokhvatov|first2 = M.|last3 = Titov|first3 = O.|date = 2016-01-01|title = The inverse beta decay: a study of cross section|url = http://stacks.iop.org/1742-6596/675/i=1/a=012003|journal = Journal of Physics: Conference Series|language = en|volume = 675|issue = 1|pages = 012003|doi = 10.1088/1742-6596/675/1/012003|bibcode = 2016JPhCS.675a2003O|issn = 1742-6596|doi-access = free}}</ref> |
||
== Reaction == |
|||
Inverse beta decay proceeds as |
|||
== Reactions == |
|||
| ⚫ | |||
=== Antineutrino induced === |
|||
| ⚫ | Inverse beta decay proceeds as<ref name=":0" /><ref name=":1" /><ref name=":2">{{Cite journal|last1 = Bellini|first1 = G.|last2 = Benziger|first2 = J.|last3 = Bonetti|first3 = S.|last4 = Avanzini|first4 = M. Buizza|last5 = Caccianiga|first5 = B.|last6 = Cadonati|first6 = L.|author-link6=Laura Cadonati|last7 = Calaprice|first7 = F.|last8 = Carraro|first8 = C.|last9 = Chavarria|first9 = A.|date = 2010-04-19|title = Observation of geo-neutrinos|journal = Physics Letters B|volume = 687|issue = 4–5|pages = 299–304|doi = 10.1016/j.physletb.2010.03.051|arxiv = 1003.0284|bibcode=2010PhLB..687..299B}}</ref> |
||
:{{subatomic particle|electron antineutrino}} + {{subatomic particle|proton}} → {{subatomic particle|positron}} + {{subatomic particle|neutron}}, |
|||
| ⚫ | where an [[electron antineutrino]] ( |
||
| ⚫ | where an [[electron antineutrino]] ({{subatomic particle|electron antineutrino}}) interacts with a [[proton]] ({{subatomic particle|proton}}) to produce a [[positron]] ({{subatomic particle|positron}}) and a [[neutron]] ({{subatomic particle|neutron}}). The IBD reaction can only be initiated when the antineutrino possesses at least 1.806 MeV<ref name=":1" /><ref name=":2" /> of kinetic energy (called the [[threshold energy]]). This threshold energy is due to a difference in mass between the products ({{subatomic particle|positron}} and {{subatomic particle|neutron}}) and the reactants ({{subatomic particle|electron antineutrino}} and {{subatomic particle|proton}}) and also slightly due to a [[Mass in special relativity|relativistic mass effect]] on the antineutrino. Most of the antineutrino energy is distributed to the positron due to its small mass relative to the neutron. The positron promptly<ref name=":2" /> undergoes matter–antimatter [[annihilation]] after creation and yields a flash of light with energy calculated as<ref name=":5">{{Cite journal|last1 = Bellini|first1 = G.|last2 = Benziger|first2 = J.|last3 = Bonetti|first3 = S.|last4 = Avanzini|first4 = M. Buizza|last5 = Caccianiga|first5 = B.|last6 = Cadonati|first6 = L.|last7 = Calaprice|first7 = F.|last8 = Carraro|first8 = C.|last9 = Chavarria|first9 = A.|date = 2013-04-15|title = Measurement of geo-neutrinos from 1353 days of Borexino|journal = Physics Letters B|volume = 722|issue = 4–5|pages = 295–300|doi = 10.1016/j.physletb.2013.04.030|bibcode=2013PhLB..722..295B|doi-access = free|arxiv = 1303.2571}}</ref> |
||
| ⚫ | |||
<math display=block>\begin{align} |
|||
| ⚫ | where |
||
| ⚫ | |||
&= E_{\rm \,\overline\nu_e} - 784 \text{ keV} |
|||
\end{align}</math> |
|||
| ⚫ | where 511 keV is the [[Electron rest mass|electron and positron rest energy]], {{math|''E''<sub>vis</sub>}} is the visible energy from the reaction, and {{tmath|E_{\rm \,\overline\nu_e} }} is the antineutrino [[kinetic energy]]. After the prompt [[electron–positron annihilation|positron annihilation]], the neutron undergoes [[neutron capture]] on an element in the detector, producing a delayed flash of 2.22 MeV if captured on a proton.<ref name=":2" /> The timing of the delayed capture is 200–300 [[microsecond]]s after IBD initiation ({{val|p=≈|256|u=us}} in the [[Borexino]] detector<ref name=":2" />). The timing and spatial coincidence between the prompt positron annihilation and delayed neutron capture provides a clear IBD signature in [[neutrino detector]]s, allowing for discrimination from background.<ref name=":2" /> The IBD [[cross section (physics)|cross section]] is dependent on antineutrino energy and capturing element, although is generally on the order of 10<sup>−44</sup> cm<sup>2</sup> (~ [[Barn (unit)|attobarns]]).<ref>{{Cite journal|last1=Strumia|first1=Alessandro|last2=Vissani|first2=Francesco|date=2003-07-03|title=Precise quasielastic neutrino/nucleon cross-section|journal=Physics Letters B|volume=564|issue=1|pages=42–54|doi=10.1016/S0370-2693(03)00616-6|arxiv=astro-ph/0302055|bibcode=2003PhLB..564...42S|s2cid=7915354}}</ref> |
||
Inverse beta decay may also sometimes refer to the interaction of an electron and proton, creating a neutrino and neutron, although this process is normally referred to as [[electron capture]]. |
|||
=== Neutrino induced === |
|||
Another kind of inverse beta decay is the reaction |
|||
:{{subatomic particle|electron neutrino}} + {{subatomic particle|neutron}} → {{subatomic particle|electron}} + {{subatomic particle|proton}} |
|||
The [[Homestake experiment]] used the reaction |
|||
:<math>\mathrm{\nu_e + \ ^{37}Cl \longrightarrow \ ^{37}Ar + e^-}</math> |
|||
to detect solar neutrinos. |
|||
=== Electron induced === |
|||
{{Main articles|Electron capture}} |
|||
During the formation of [[Neutron star|neutron stars]], or in radioactive isotopes capable of [[electron capture]], neutrons are created by electron capture: |
|||
:{{subatomic particle|proton}} + {{subatomic particle|electron}} → {{subatomic particle|neutron}} + {{subatomic particle|electron neutrino}}. |
|||
This is similar to the inverse beta reaction in that a proton is changed to a neutron, but is induced by the capture of an electron instead of an antineutrino. |
|||
== See also == |
== See also == |
||
Latest revision as of 13:54, 9 July 2024
In nuclear and particle physics, inverse beta decay, commonly abbreviated to IBD,[1] is a nuclear reaction involving an electron antineutrino scattering off a proton, creating a positron and a neutron. This process is commonly used in the detection of electron antineutrinos in neutrino detectors, such as the first detection of antineutrinos in the Cowan–Reines neutrino experiment, or in neutrino experiments such as KamLAND and Borexino. It is an essential process to experiments involving low-energy neutrinos (< 60 MeV)[2] such as those studying neutrino oscillation,[2] reactor neutrinos, sterile neutrinos, and geoneutrinos.[3]
Reactions
[edit]Antineutrino induced
[edit]Inverse beta decay proceeds as[2][3][4]
ν
e +
p
→
e+
+
n
,
where an electron antineutrino (
ν
e) interacts with a proton (
p
) to produce a positron (
e+
) and a neutron (
n
). The IBD reaction can only be initiated when the antineutrino possesses at least 1.806 MeV[3][4] of kinetic energy (called the threshold energy). This threshold energy is due to a difference in mass between the products (
e+
and
n
) and the reactants (
ν
e and
p
) and also slightly due to a relativistic mass effect on the antineutrino. Most of the antineutrino energy is distributed to the positron due to its small mass relative to the neutron. The positron promptly[4] undergoes matter–antimatter annihilation after creation and yields a flash of light with energy calculated as[5]
![{\displaystyle {\begin{aligned}E_{\text{vis}}&=511{\text{ keV}}+511{\text{ keV}}+E_{\rm {\,{\overline {\nu }}_{e}}}-1806{\text{ keV}}\\[2pt]&=E_{\rm {\,{\overline {\nu }}_{e}}}-784{\text{ keV}}\end{aligned}}}](https://wikimedia.org/enwiki/api/rest_v1/media/math/render/svg/627515db485cf4f51529460246187224a6156ec9)
where 511 keV is the electron and positron rest energy, Evis is the visible energy from the reaction, and is the antineutrino kinetic energy. After the prompt positron annihilation, the neutron undergoes neutron capture on an element in the detector, producing a delayed flash of 2.22 MeV if captured on a proton.[4] The timing of the delayed capture is 200–300 microseconds after IBD initiation (≈256 μs in the Borexino detector[4]). The timing and spatial coincidence between the prompt positron annihilation and delayed neutron capture provides a clear IBD signature in neutrino detectors, allowing for discrimination from background.[4] The IBD cross section is dependent on antineutrino energy and capturing element, although is generally on the order of 10−44 cm2 (~ attobarns).[6]
Neutrino induced
[edit]Another kind of inverse beta decay is the reaction
ν
e +
n
→
e−
+
p
The Homestake experiment used the reaction
to detect solar neutrinos.
Electron induced
[edit]During the formation of neutron stars, or in radioactive isotopes capable of electron capture, neutrons are created by electron capture:
p
+
e−
→
n
+
ν
e.
This is similar to the inverse beta reaction in that a proton is changed to a neutron, but is induced by the capture of an electron instead of an antineutrino.
See also
[edit]References
[edit]- ^ Daya Bay Collaboration; An, F. P.; Balantekin, A. B.; Band, H. R.; Bishai, M.; Blyth, S.; Butorov, I.; Cao, D.; Cao, G. F. (2016-02-12). "Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay". Physical Review Letters. 116 (6): 061801. arXiv:1508.04233. Bibcode:2016PhRvL.116f1801A. doi:10.1103/PhysRevLett.116.061801. PMID 26918980. S2CID 8567768.
- ^ a b c Vogel, P.; Beacom, J. F. (1999-07-27). "Angular distribution of neutron inverse beta decay". Physical Review D. 60 (5): 053003. arXiv:hep-ph/9903554. Bibcode:1999PhRvD..60e3003V. doi:10.1103/PhysRevD.60.053003.
- ^ a b c Oralbaev, A.; Skorokhvatov, M.; Titov, O. (2016-01-01). "The inverse beta decay: a study of cross section". Journal of Physics: Conference Series. 675 (1): 012003. Bibcode:2016JPhCS.675a2003O. doi:10.1088/1742-6596/675/1/012003. ISSN 1742-6596.
- ^ a b c d e f Bellini, G.; Benziger, J.; Bonetti, S.; Avanzini, M. Buizza; Caccianiga, B.; Cadonati, L.; Calaprice, F.; Carraro, C.; Chavarria, A. (2010-04-19). "Observation of geo-neutrinos". Physics Letters B. 687 (4–5): 299–304. arXiv:1003.0284. Bibcode:2010PhLB..687..299B. doi:10.1016/j.physletb.2010.03.051.
- ^ Bellini, G.; Benziger, J.; Bonetti, S.; Avanzini, M. Buizza; Caccianiga, B.; Cadonati, L.; Calaprice, F.; Carraro, C.; Chavarria, A. (2013-04-15). "Measurement of geo-neutrinos from 1353 days of Borexino". Physics Letters B. 722 (4–5): 295–300. arXiv:1303.2571. Bibcode:2013PhLB..722..295B. doi:10.1016/j.physletb.2013.04.030.
- ^ Strumia, Alessandro; Vissani, Francesco (2003-07-03). "Precise quasielastic neutrino/nucleon cross-section". Physics Letters B. 564 (1): 42–54. arXiv:astro-ph/0302055. Bibcode:2003PhLB..564...42S. doi:10.1016/S0370-2693(03)00616-6. S2CID 7915354.