What is Electron capture: Definition and 39 Discussions

Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. This process thereby changes a nuclear proton to a neutron and simultaneously causes the emission of an electron neutrino.

p + e− → n + νe Since this single emitted neutrino carries the entire decay energy, it has this single characteristic energy. Similarly, the momentum of the neutrino emission causes the daughter atom to recoil with a single characteristic momentum.
The resulting daughter nuclide, if it is in an excited state, then transitions to its ground state. Usually, a gamma ray is emitted during this transition, but nuclear de-excitation may also take place by internal conversion.
Following capture of an inner electron from the atom, an outer electron replaces the electron that was captured and one or more characteristic X-ray photons is emitted in this process. Electron capture sometimes also results in the Auger effect, where an electron is ejected from the atom's electron shell due to interactions between the atom's electrons in the process of seeking a lower energy electron state.
Following electron capture, the atomic number is reduced by one, the neutron number is increased by one, and there is no change in mass number. Simple electron capture by itself results in a neutral atom, since the loss of the electron in the electron shell is balanced by a loss of positive nuclear charge. However, a positive atomic ion may result from further Auger electron emission.
Electron capture is an example of weak interaction, one of the four fundamental forces.
Electron capture is the primary decay mode for isotopes with a relative superabundance of protons in the nucleus, but with insufficient energy difference between the isotope and its prospective daughter (the isobar with one less positive charge) for the nuclide to decay by emitting a positron. Electron capture is always an alternative decay mode for radioactive isotopes that do have sufficient energy to decay by positron emission. Electron capture is sometimes included as a type of beta decay, because the basic nuclear process, mediated by the weak force, is the same. In nuclear physics, beta decay is a type of radioactive decay in which a beta ray (fast energetic electron or positron) and a neutrino are emitted from an atomic nucleus.
Electron capture is sometimes called inverse beta decay, though this term usually refers to the interaction of an electron antineutrino with a proton.If the energy difference between the parent atom and the daughter atom is less than 1.022 MeV, positron emission is forbidden as not enough decay energy is available to allow it, and thus electron capture is the sole decay mode. For example, rubidium-83 (37 protons, 46 neutrons) will decay to krypton-83 (36 protons, 47 neutrons) solely by electron capture (the energy difference, or decay energy, is about 0.9 MeV).

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  1. B

    A Electron capture in a molecule

    Hello! If I have a (diatomic for simplicity) molecule containing a nucleus that decays by electron capture, are there any theoretical calculations of how that would behave in practice? For example would the lifetime change? Would the resulting molecule still be bound? For example if I start with...
  2. Anonymous324

    I Electron mass conversion during electron capture

    In electron capture, a proton turns into a neutron and a neutrino is emitted. Is (without counting the mass difference between neutron and proton and the mass of the neutrino) the mass of the electron converted into energy in the form of gamma radiation?
  3. T

    B Pair Instability Supernovae & Electron Capture Supernovae

    Hi! I've been browsing the internet for information about supernovae and I came across this chart describing 4 types of core collapse causes (the chart may have copied weirdly because not all the information fits into this text box): Cause of collapse Progenitor star approximate initial mass...
  4. I

    B What happens during electron capture physically?

    I wonder if someone could explain what is known about electron capture in which a proton captures an electron which then becomes a neutron? I have read that a proton which has two up quarks and a single down quark will have the the creation and destruction of multiple quark - antiquark pairs...
  5. R

    Decay Processes of 39Ca, 39Ar, and 40K

    Could I please check if my answers to the following three questions are correct? My answers are in bold. 1. How would you expect 39Ca to decay? a) β+ or electron capture (EC) b) Electron capture only c) β- d) α 2. How would you expect 39Ar to decay? a) β+ or electron capture (EC) b) Electron...
  6. O

    I Electron capture and electron transitions.

    When a nucleus captures an electron from the innermost orbit, its proton number reduces one. Therefore, energy levels in the atom have to change accordingly, meaning all the electrons have to move lower energy levels. From this point of view, during an electron capture, can it be said that the...
  7. charlesmartin14

    I Do Fermi and Gamow-Teller transitions only refer to isospin

    Do Fermi and Gamow-Teller transitions only refer to changes in isospin , as in beta decay and orbital electron capture
  8. I

    Beta decay, electron capture Q value

    Homework Statement Find the ##Q## value for electron capture of ##^{196}Au##. Homework Equations ##Q_\epsilon = [m(^AX)-m(^AX')]c^2-B_n## The Attempt at a Solution How do I know if I have an ##K##- or ##L##-shell for the electron? Assuming I have an ##K## shell taking ##B_n = \; ^{196m1}Au##...
  9. kiwaho

    I Can electron beam accelerate electron capture beta decay?

    Some nuclides undergo decay of electron capture or beta plus. Can electron beam with appropriate energy accelerate electron capture beta decay? Same scenario: If I am looking for something, and my friend kindly hands it over to me, then I say thanks, because my seeking time is shorten.
  10. D

    Electron Capture: Explaining Too Many Neutrons

    Homework Statement My book is saying that if a nucleus has too many neutrons beta minus decay or electron capture is going to happen. The nucleus wants to get rid of a neutron so it is going to send out one electron and an antineutrino that originally comes from the neutron. But what I don't...
  11. Garlic

    Electron capture in fully ionised nuclei

    Hello everyone, What happens if an isotope that normally decays through EC has no electrons at all? For example how does 7Be4+ decay?
  12. N

    Secondary effect of Electron capture and Internal conversion

    During Internal conversion, the nucleus transfer some energy to an electron in K-shell cause the electron eject out of the atom. After which there left a hole in K-shell then either by releases auger electron or characteristic X-ray the atom de-excited itself. During Electron capture, a proton...
  13. N

    Electron Capture by alpha particle -- Frequency of photon?

    Homework Statement Electron with KE = 50eV is captured by Alpha particle, ie. HE++. Calculate the frequency of the emitted photon. Homework Equations KE = m/2 v^2; E=hf, En = Z^2*-13.6eV/n^2 The Attempt at a Solution Energy before = Energy after 50eV = 4*-13.6eV/1 + hf f = 1200nm
  14. N

    (Check solution) Frequency of light after electron capture?

    Homework Statement An alpha particle: He++ captures an electron of a given kinetic energy. To conserve energy, it emits light, hf. How would one calculate the frequency? Homework Equations E=hf En = (Z^2 *-13.6eV)/(n^2) The Attempt at a Solution Calculate En. Then KE = Photon + En. Solve for...
  15. Garlic

    Muon and Electron Capture: Exploring the Differences

    I have read that an ordinary muon capture happen with this equation below: μ + p -> n + vμ It looks the same as the electron capture e + p -> n + ve I don't understand why there isn't any additional energy in the system, although a muon has a greater mass. Also, why isn't there an additional...
  16. karakele

    Concerns about double beta decay plus/double electron capture

    Hello fellas! Ok, so we have the isotope Nickel-58 which can decay (still theoritically) to Iron-58 through double beta decay plus (bb+), my question is... imagine this decay is actually demonstrated (just figure it), so the transmutation into the iron isotope actually works... would the ejected...
  17. P

    Electron capture and heavy nuclei

    Hi, is it true that the heavy atoms decaying only by electron capture should have globally a half-life shorter than ligher nuclei (decaying also only by electron capture)? This assumption comes from the fact heavy atoms have inner electron "closer" to their nucleus than the lighter ones and so a...
  18. S

    Q-Value Electron Capture Kr-81

    Homework Statement Calculate the Q-value for the electron capture beta decay of Kr-81 (Answer in MeV, correct to 6 significant figures) Atomic Masses (amu) Kr-81 = 80.916592(3) Br-81 = 80.916291(3) proton 1.00727647 neutron 1.00866501 electron 0.0005485803...
  19. David Carroll

    Electron Capture and Coulomb's Law

    Sorry for the brevity of the post, but eloquence has never been my strong point. Here's my question: In a proton-surfeited atom, a proton captures an electron to form a neutron. Now, according to Coulomb's law, the magnitude of the electrostatic force field is equal to (kq1q2)/d2, where k is...
  20. R

    Electron Capture - X-ray or gamma-ray?

    I may be being a bit pedantic but when an electron "falls" (or is captured by) into the nucleus, does the outer shell electron that fills its place result in an x-ray or a gamma-ray being emitted? Or would it depend on the energy transition? Thanks for any ideas.
  21. R

    Beta+ decay or electron capture?

    Homework Statement Homework Equations See below. The Attempt at a Solution We have β+ decay ##X_{Z}^{A} \rightarrow Y_{Z-1}^{A}+ e^{+}+\upsilon _{e}## which leads to the mass condition ##M(A,Z)>m(A,Z-1)+2m_{e}##. We have electron capture ##X_{Z}^{A} + e^{-}\rightarrow Y_{Z-1}^{A}+ \upsilon...
  22. N

    Energy Release of Electron Capture to Ground State

    Hello All, I am pretty sure that when a nucleus decays via e.c. and goes to the ground state all of the excess energy is released with the emission of the neutrino but was wondering if anyone could confirm/give a reference for this. Thanks!
  23. F

    Electron Capture vs Positron Emision

    I'm having some slight confusion over what seems to be a violation of conservation of mass: Both electrons and positrons have positive mass, so now consider an atom that undergoes a beta decay, and so has it's mass changed by the difference in mass between a proton and a neutron. How does it...
  24. R

    Calculating Kinetic Energy and Recoil Speed of Nucleus after Electron Capture

    Hi I have an atom with nuclear charge Z, mass M and no electrons (a bare nucleus) which captures an electron into its ground state. I am asked to calculate the kinetic energy and the recoil speed of the nucleus after the electron capture... I have the Z^2 (-13,6 eV) as usual, as the...
  25. E

    Nuclear Physics - Difference between electron capture and beta plus decay

    So my question has a few parts to it. First, if an atom is decaying and the proton (Z) number is decreasing in the decay process, am I correct in assuming that the nucleus is either decaying by electron capture of beta plus emission? Secondly, I understand that beta plus emission can only...
  26. binbagsss

    What is the difference between proton-electron collison adn electron capture?

    Is it the same thing? If not what is the key difference between the two and what conditions would make the weak interactions governing the two more favourable than the other one?, (My thoughts are along the lines of , that proton-electron collision is referring to free electrons or free...
  27. binbagsss

    Electron Capture and B+ decay

    When electron capture and β+ decay occur in proton-rich nuclide, in order to obtain a lower E state, is the lower E state of the atom reached by 1 electron capture of the same energy as the state reached due to one β+ decay? - I ask because I know that in order for EC or B+ to occur, the...
  28. edpell

    Metals and free electron capture

    I am not a condensed matter physicist. Can someone explain the situation for free electrons in a metal to me. It seems like they would head straight for the nearest positively charged lattice nuclei. As it got very close <3 fermi it would radiate a lot because it is accelerating. So after a few...
  29. L

    Electron capture vs internal conversion electrons vs auger electrons

    what is the differece between internal conversion electrons, electron capture and auger electons? i don't understand. The name suggests electron capture and internal conversion electrons are the same thing... but then when i look it up internal conversion electrons seem to be the same as auger...
  30. V

    Solve Electron Capture: Population Ratio of 2p1/2 & 2p3/2 States

    Homework Statement Consider a process of a capture of an electron into 2p1/2 and 2p3/2 states of hydrogen atom. Find a population ratio of these two states after the capture. Homework Equations ? The Attempt at a Solution I don't know where to start on this question. As far as I know...
  31. B

    Electron Capture in Pair Production

    During electron-positron pair production, does electron capture always happen? Gracias
  32. R

    Electron capture, electrons binding energy

    Homework Statement Hello! I am doing some calculations with electron capture for the reaction \stackrel{196}{79}Au\stackrel{EC}{\rightarrow}\stackrel{196}{78}Pt The Q-value for the reaction is Q=[m(\stackrel{196}{79}Au-\stackrel{196}{78}Pt]c^2-B_{n} where B_{n} stands for electron's...
  33. K

    Electron Capture: Nucleus Capturing Revolving Electron Shell

    when nucleus capture the electron revolving in the shell?
  34. A

    Calculating Kinetic Energy Q for CA-41 Electron Capture

    Homework Statement calculate the kinetic energy Q for CA-41 via electron capture Homework Equations Q = (mparent-mdaughter)*c2 The Attempt at a Solution CA 41 has 20 protons and 21 neutrons, so will it become K with 19 protons and 22 neutrons? (the book also stated that the...
  35. N

    Electron Proton Collisions and Electron Capture

    What is the difference between electron capture, and electron-proton collions? My textbook has the feynman diagram of electron capture as a proton decaying into a neutron, and the proton emmiting a W+ boson, which is received by an electron, which then decays into a neutrino. However, the...
  36. K

    Producing Neutrons: Electron Capture vs Electron-Proton Collisions

    According to a textbook that I was looking at, electron capture and electron-proton collisions both produced a neutron and an antineutrino, but one was mediated by a W+ particle and the other by a W-. Is this correct, or are they interchangeable?
  37. T

    Beta decay and electron capture.

    Recently the radation physics class I am taking reviewed decay and I wondered how beta minus decay and electron capture can both emit neutrinos. I tried asking my professor, but I do not think I explained my question well enough to him. To explain my mindset, imagine you have only one...
  38. C

    Induce radioactive decay via electron capture?

    Hi, Is it possible to induce decay in a radioactive element by introducing vast amounts of high-energy electrons in the hope that they would be absorbed via electron capture? I was thinking about how to use up all the reactor waste that the US generates (I live in Washington State, a great...
  39. Reshma

    Electron Capture: Explaining Conditions & Occurrence

    Electron capture is a form of beta-decay. Here, an orbital electron(usually in K-shell) can combine with proton to form a neutron and a neutrino. p + \beta^{-}\rightarrow n + \nu Can someone explain me why this phenomenon occurs and under what conditions?