Decay Definition and 998 Threads

  1. X

    Beta Decay of He3 Atom: Electron Emission vs. Shell Occupancy

    Does this decay leave the He3 atom with only one electron? The only decay productsas far as I can tell are the electron and antineutrino, so it seems like the atom would only retain the original H3 electron. Now if that's the case, why is the beta decay electron emitted rather than fitting...
  2. M

    Simulate Gamma Rays from Radioactive Decay

    Hello, I am trying to simulate the gammas from certain radioactive decays but I am really puzzle as to how to approach this. The site I'm using as a reference lists the intensities of the different gammas corresponding to an specific decay. The thing that confuses me is that, for example...
  3. M

    Antimatter decay rate in a book?

    I read a book in which it proposed that anti-matter "decayed" faster than matter, right after the big bang, which is why there isn't an around. Unfortunately, I've forgotten exactly what the writer meant, and who it was... Can someone tell me who the writer was, and in what book it was...
  4. X

    Kinetic energy of electron after beta decay

    Is that a constant? If not, is there an equation that allows us to calculate its kinetic energy based on the properties of the atom it came from?
  5. S

    Calculating Half-Life from Radioactive Decay

    Homework Statement After 25 years, 60% of a radioactive material decays. What is the half-life? Homework Equations I used a ratio of 25/.60= x/.50 The Attempt at a Solution I also tried this ratio as 25/.40= x/.50 I am not really sure what equation I should be using but this...
  6. S

    Pion Decay and Relativity Question

    Homework Statement 42. If a charged pion that decays in 10−8 second in its own rest frame is to travel 30 m in the laboratory before decaying, the pion’s speed must be most nearly (A) 0.43 × 108 m/s (B) 2.84 × 108 m/s (C) 2.90 × 108 m/s (D) 2.98 × 108 m/s (E) 3.00 × 108 m/s Homework...
  7. P

    Do Third Generation Quarks Decay at Slower Rates?

    I know that things moving closer to the speed of light will decay at slower rates, but does this include the decay of third generation quarks into second and then first generation quarks? If a third generation quark is created and in an area of the universe where things are moving extremely...
  8. X

    How to Determine Neutrino Energy in Pion Decay?

    Homework Statement Pions can decay via the reaction π+ → μ+ νμ. Show that the energy of the neu- trino in the rest frame of the pion is given by E_v = \frac{m^2_∏-m^2_μ}{2m_∏} Pions with energy Eπ in the laboratory frame (Eπ >> mπc2) decay via the above reaction. Show that the...
  9. karush

    MHB Radioactive Substance Decay: ~14g Left After 3 Years

    If 40 grams of radioactive substance decomposes to 20 grams in 2 years, then to the nearest gram the amount left after 3 years is well i used the $N(t)=N_{0}e^{-kt}$ So $20=40e^{-k2}$ thus deriving k=.3466 Thus $N(3) = 40e^{-.3466(3)}$ resulting in: $N(3)= 14.1410$ or approx $14g$ just...
  10. A

    Understanding Electron Capture and Beta Decay: Is a Quark Conversion Involved?

    Hi, From what I understand, Electron Capture is when a proton absorbs an electron, converts into a neutron and releases a neutrino (p + e- = n + v.) I also understand that a proton is composed of two up quarks and a down quark and a neutron is composed of two down quarks and an up quark. Here...
  11. G

    Proton beta plus decay -proton proton chain

    proton beta plus decay --proton proton chain Im a biologist so forgive the ignorance. In beta-plus decay, a proton decays into a neutron and emmits a β+ and an electron neutrino. If the neutron is more massive than the proton where did the extra mass come from? Im asking in the context...
  12. D

    Determining electric permittivity from time constant decay

    Homework Statement a slab of some insulator with an unknown permittivity ε. To determine ε experimentally I go to the lab and insert the slab in between the plates of a capacitor whose plate spacing exactly matches the width of the slab. I observe that the time constant of exponential...
  13. I

    Do Electrons and Positrons Have a Finite Lifetime?

    I am pretty sure they don't, but Wikipedia says that their lifetime is about 10^26 years. Then it says they are stable because they are the lightest particle to have an electric charge. I am confused now. It can't decay because if it did, it would violate charge conservation, since two lighter...
  14. P

    Particle composition vs particle decay

    Ive read that elementary particles can decay. I am trying to understand how this can be with a particle that has no composition. So i have two questions: If elementary particle A decays into particles B and C, then why can't we say that A is composed of B and C? If an elementary particle can...
  15. M

    What Happens to Decay Energy in U-238 to Th-234 Transition?

    Hello, I need some help understanding this. http://atom.kaeri.re.kr/cgi-bin/decay?U-238%20A it says that 79% of the time U-238 goes to the ground state of Th-234 emitting a 4.198 MeV alpha ray. But the difference between the ground state of U-238 and Th-234 is more than 4.198 MeV. What...
  16. F

    Calculating Decay Constant Without Initial Value

    Radioactive sample activity is said decreases by factor 5 during 2-h interval. How to find the decay constant? If the given initial value is not given? I don't know how to calculate.
  17. P

    Exponential decay, but results reach 0

    So I have a situation where the results in a table (x and y), where y reaches 0. According to my understanding, mathematically, exponential decay can never reach 0, right? So does that mean that I can't use an exponential curve of best fit with the results in my table (x = 0,1,2,3), (y = 4...
  18. M

    Equation of the line for a second order decay

    What is it?! I have tried plotting dummy data showing y values halving as x values double and no simple type of equation results (ie exponential, power, polynomial etc) - is this true? I thought such a standard function would be a simple one!
  19. P

    .Higgs Boson Decay: Does the Third Diagram Exist?

    Hello, I had a doubt about a specific Higgs boson decay. In the process H -> c+\bar{s}+W^-, where c is the charm quark, \bar{s} the anti strange quark, in tree level I wrote the diagrams sent in attachment. My question is: does the third diagram exist? I do know that the s...
  20. I

    Beta+ Decay: Making Sense of Proton-to-Neutron Conversion

    This has been really bugging me. Beta plus decay is when a proton emits a positron in order to convert to a neutron, thus making the element more stable. If protons are less massive than neutrons, how does that make sense? You have less mass, emit some, and end up with more? I must be missing...
  21. D

    Solving Higgs Decay Invariant Averaged Amplitude Problem

    Homework Statement I have decay of Higgs to fermion and antifermion and I need to find out the invariant, averaged amplitude. And I wrote down the Feynman diagram, and calculated everything and I came to this part: \langle|M|^2\rangle=\frac{g_w^2}{4}\frac{m_f^2}{m_w^2}(4p_1\cdot...
  22. S

    Understanding the Different Modes of Potassium-40 Decay

    1)Is Potassium-40 dangerous material?How dangerous is it?Does it belong to restricted materials? 2)Why Potassium-40 decays in such different modes such as beta decay,electron capture, and positron decay?What could be done to prevent it decay in other ways with exept beta decay?Or what could be...
  23. R

    Does amount of electrons orbiting an atom effect rate of radioactive decay?

    Do ions have a measurably different rate then their neutral counterpart or does the rate of radioactive decay and electrons have no correlation? Also, when a source states an elements half life is that the same for all of its isotopes?
  24. P

    Proportion of energy gained by decay products

    What is the proportion of energy gained by the decay products when a nuclei undergoes alpha decay?
  25. A

    Gamma Ray Decay to potential watts

    I'm interested in calculating how much power (in Watts) could be produced (assuming a 100% conversion efficiency between Gamma Rays and electrical power) from gamma decay of a 60 Co -> 60 Ni. How long would this reaction last? Just a few seconds or longer? Are there any decays that last for a...
  26. I

    Do Neutron Stars Eventually Decay Into Black Holes?

    After reading "The Five Ages of the Universe" by Greg Laughlin and Fred Adams, I wondered, if all matter composed of ordinary atoms (protons decay) decay, and black holes decay due to Hawking Radiation, do neutron stars decay in any way? They are composed entirely of neutrons that are kept...
  27. C

    Can Z decay into a neutral pion?

    I wondered if the following decay was possible: \Xi^0 \to \Lambda + \pi^0 The only mechanism I can think of is that a strange quark of the Lambda particle emits a Z and becomes a down quark followed by the Z creating a up-antiup pair. But I'm not sure whether the strange to up transition (by...
  28. S

    Does radioactive decay always result in a daughter nuclide in an excited state?

    Hello, Would all radioactive decay lead to a daughter nuclide in a "nuclear excited" state, and if so, would this indicate that gamma rays are emitted in order for the nuclear ground/stable state to be reached after any decay? Also, if nuclear decay occurs b/c of the imbalance of...
  29. R

    How Does One Proton Decay Per Year Impact Our Health?

    We're made of roughly 10^28 protons. Let's imagine that the average lifespan of a proton were 10^28 years even though it is much higher. That would mean one proton per year would decay in our body. How much harm would one proton decay cause us?
  30. T

    Is Beta Positive Decay a Viable Energy Source for Long-Term Power?

    Okay, I have had a idea for some time and I want to see if it will work. first you get Magnesium 24 launch protons at 20 Mev then a decay happens. Now you have Na22 sodium 22 beta positive decays into a anti electron of 1 Mev with its counter particle they annihilation into 2 gamma rays which...
  31. G

    Exploring Alpha, Beta, Gamma Decay & Conservation of Mass/Energy

    I am completing an assignment that is covering alpha, beta, and gamma decay. I am going to try and keep this as general as possible, as I want to figure this out myself but I just looking for feedback to make sure I am on the right track. I noticed that after alpha decay, the mass of the...
  32. C

    Calculate the KE of an electron emitted from the beta decay of a neutron

    Homework Statement What is the maximum kinetic energy (in keV to 3 significant figures) of an electron emitted in the beta decay of a free neutron? Write down the decay equation using accepted notation. Mass of a Neutron: 1.008665 u Mass of a Proton: 1.007276 u Mass of an Electron...
  33. N

    Is the Decay of Δ⁺ to p⁺ and π⁰ Possible?

    Homework Statement Are the following reactions possible? If yes, explain why and how the reaction occurs. If no, explain why. ... \Delta^+ \to p^+ + \pi^0"Homework Equations NA The Attempt at a Solution First of all, it wouldn't break any conservation law, hence it is possible (or is this...
  34. I

    Question about current decay in R-L circuit

    Hello I am reading Young, Freedman's University physics and I have some questions about the sign conventions followed in getting the equations for the current decay in the R-L circuit. I have attached two snapshots which will help the discussions. Consider the series R-L circuit as shown...
  35. A

    Why aren't the daughter isotopes of alpha decay charged?

    For example, when a radioactive isotope of Uranium undergoes alpha decay, a radioactive isotope of Thorium is formed. Why isn't this daughter isotope charged?
  36. bayan

    Quantum tunneling and radioactive decay.

    Homework Statement The edge of a nucleus can be roughly modeled as a square potential barrier. An alpha particle in an unstable nucleus can be modeled as a particle with a specific energy, bouncing back and forth between these square potential barrier. Consider a nucleus of radius r and an...
  37. 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...
  38. O

    Positron emission (Beta + decay)

    Why does β+ decay occur? If protons are stable and all baryons eventually decay to protons, then how is it that protons can 'decay' to a neutron? What causes this to happen? (I assume it isn't as frequent as β- decay, or up and down quarks would be coming and going constantly, and we'd be...
  39. M

    Fundamental Particles - Meson Decay Question

    Homework Statement The pion-zero meson has its mass quoted as 135.0MeV/c2. It decays into two gamma rays: ∏0 → γ + γ b) Assuming the ∏0meson to be initially at rest, calculate the energy and hence the wavelength of the two gamma rays. Homework Equations E= hc/λ The Attempt at a...
  40. A

    Finding the energies of 2 photons from a decay of a travelling mass

    Homework Statement Mass M traveling at v=c/3 decays into 2 photons in x and -x directions. Mass M orginally formed by mass m traveling at v=3c/5 hitting a stationary mass m. This gives M v=c/3 and M=3m/√2. Homework Equations E=K + mc^2 p = gamma m v E = gamma m c^2 K =...
  41. B

    Nuclear Decay question without knowing N0 or N ?

    Nuclear Decay question without knowing N0 or N ?? Homework Statement Ok so what I have an Am sample which emits alpha particles at a rate of 70Bq in 1997 and asks for the activity 8 years later (the half life of Am being 432.2 years) I found this to be 69.108 Bq, first of all does this sound...
  42. D

    Request for Link on orbital decay energy characteristics

    While reading an older article by Schrodinger on Causality a question occurred to me about the nature of energy/time characteristics of light emitted by electron orbital decay. I have been thinking for some time on the relationship/contrasts between generation of lower frequency (ie radio)...
  43. A

    Lorentz gamma factor in a decay of arbitrary leptons

    Homework Statement Show that the Lorentz gamma factor in the decay K^+ \rightarrow l^+ \nu_l can be written as \gamma = \frac{m_K^2 + m_l^2}{2m_K m_l} where nu is either e or mu. The Attempt at a Solution I'm stuck on a part of the proof. I think I understand most of it...
  44. N

    Understanding Nucleus Decay: Nitrogen-14 to Carbon-11 Transformation Explained

    A proton collides with a nucleus of nitrogen-14 (atomic number 7). This collision produces a nucleus of carbon-11 (atomic number 6) and what else? My attempt: 14/7N + proton -----> 11/6C + alpha particle? I know it cannot be gamma decay, but I'm not sure if it's alpha or beta decay and what...
  45. J

    Energy release from beta plus decay

    [b]1. Astatine-210 decays through a beta-plus decay process. Use the table in section 29-8 (see the link above) to find the relevant masses for this decay, and calculate the energy (in MeV) released by the decay of one such atom. You can neglect the mass of the neutrino that is one of the decay...
  46. D

    Would like suggestions for studying igneous rocks and radioactive decay

    I don't have much of a scientific background, but I am interested in learning about geology. More specifically I would like to study the nature of igneous rocks, particularly their formation through volcanic processes. I'm also very much interested in understanding how the process of...
  47. A

    Kaon decay to a lepton and associated neutrino

    Homework Statement Draw the lowest-order Feynman diagram for the decay: K^+ \rightarrow l^+\nu_l Homework Equations Kaon structure is given as u\bar{s} The Attempt at a Solution So I know that you can get a lepton and an associated neutrino from a W decay, where the strange...
  48. A

    Is activity in radioactive decay a differential?

    According to my textbook, the decay constant is the probability that a radionuclide will decay in any second (hence the unit s^-1) and so the total number of radionuclides decaying at any second, i.e. the activity, is λN but this is also the rate of change of N thus dN/dt = -λN Surely...
  49. R

    Gamma radiation decay question.

    Homework Statement The radioactive substance emits gamma radiation. Complete the equation below for the disintegration of the nuclei of this substance. Homework Equations ^{24}_{11}Na^{*} \rightarrow ^{?}_{?}Na + ? The Attempt at a Solution ^{24}_{11}Na^{*} \rightarrow...
  50. H

    Nuclear decay emission: deterministic modeling?

    Is it possible, in theory, that a radioisotope undergoing nuclear decay (eg. alpha particle emission) can be modeled so as to determine the origin and/or direction of the emitted particle? For instance, perhaps one could model nucleon interactions deterministically and observe that when the...
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