Questions tagged [nuclear-physics]

Nuclear physics is the study of the composition, behavior and interaction of atomic nuclei and their constituent parts.

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Is high temperature **required** for nuclear fusion?

Tl;dr: Can fusion be achieved only by speeding up particles to high enough speeds to smash into each other? I know that it is necessary for protons, or any oppositely-charged particles for that ...
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1answer
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*Why* were the Chernobyl control rods tipped with graphite?

I understand the graphite tips of the boron control rods displaced water (a moderator) which lead to an increased reaction rate, rise in temperature and steam pressure etc. Question: why were the ...
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Is the strong potential repulsive for high distances?

The negative region in a potential is attractive and the positive region is repulsive. At least in case of the coulomb potential: When having a look at the strong potential it is obvious that the ...
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1answer
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Loss of mass in a fission reaction

I was reading a textbook for fun this summer and I had difficulty to understand this uranium 235 fission reaction: $$\ _0^1n + \ _{92}^{235}U \rightarrow \ _{38}^{94}Sr + \ _{54}^{139} Xe + 3 \ _0^...
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Role of the Yukawa potential

What is the Yukawa potential converging to zero? Afaik the strong potential rises with the distance between quarks, hence, it should rise accordingly.
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Momentum of neutrino and beta particle [on hold]

In carbon-14 decay beta particles with end point energy 0.155MeV are emitted. A beta particle with 0.025MeV energy is emitted at 135 degree to the direction of motion of recoiling nucleus ,calculate ...
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1answer
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Why does formation of iron in stars doesnt produce any energy?

Why does the formation of iron in the stars doesnt produce any energy, i have a hunch that it might have something to do with the fact that iron has the highest binding energy per nucleon and hence (...
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Interpretation of Bi-207 decay spectrum

I measured the decay spectrum of Bi-207 as a beta source with scintillation detector and now I am trying to interpret the information given by the spectrum. As far as I know, the Bi-207 nuclei decay ...
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0answers
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Are quarks from two different nucleons less distant than the quarks inside a nucleon?

I am curious about atomic nucleus and the possibility that baryons could be very close to each other, but no so close. And, are protons positioned favoring the surface and neutrons more in the center ...
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What triggers a nuclear decay?

I am not a physicist but I have been wondering about this: I understand that the decay of a nucleus is a random event and one cannot predict exactly when it will happen for a particular nucleus. ...
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Fractional electric charges

Since the Oil droplet experiment we are talking about elementary electric charges: Charge quantization is the principle that the charge of any object is an integer multiple of the elementary charge....
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How am I supposed to get this answer? [closed]

This question is from the Oxford Physics book, and I didn't understand how to get the answer. I'm assuming that the equation that I'm supposed to use E=mc^2 to solve the equation.
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1answer
33 views

Why don't we consider the Gamow factor when configuring the cyclotron?

Most of the time, during a collision the repulsive force between the protons will beat the attractive force that binds the nucleus together and the whole thing is torn apart. But very occasionally, ...
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Finding stable superheavy elements

Finding new stable superheavy elements is big interests in nuclear physics. Nuclides with $Z>92$ are not found in nature, but can be made artificially. Usually these nuclides become more unstable ...
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On the size of positronium

How can we simply apply the bohr model on a positronium as the positronium doesn't even have a nucleus or nucleus-like entity like in a hydrogen like atom. Moreover this implies that the first ...
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21 views

Method for calculating nuclear magnetic moments

I am having difficulties computing the magnetic moment for an even-odd (proton-neutron) nucleus. The formula is: $$\mu_J=g_J\times j\times \mu_N$$ I checked this helpful post: When calculating ...
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1answer
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Why scattered electron waves from different parts of a nucleus interfere destructively?

We know that, $\sigma (\theta)=\sigma _M (\theta){F(q)}^2$, where $\sigma _M (\theta)$ is the scattering cross section for a point nucleus while $\sigma (\theta)$ is the observed scattering cross ...
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Increasing total anti-neutrino cross section [duplicate]

Is there a method for increasing the total microscopic cross section for an interaction between an anti-neutrino and a nucleus of Titanium 48?
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1answer
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Increase the Inverse Beta Decay Cross Section for Ti-48

Is there a theoretical way to increase the cross section of inverse beta decay for Ti-48? This would be any method for increasing the likelyhood that Ti-48 absorbs an anti neutrino and creates Ca-48 ...
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Need some literature recommendation - Quasi-Free electron scattering (Nuclear Physics)

I'm not sure if this is the right place for this kind of questions, but here it goes. I'm a last year undegrad and I'm currently working on a project with my professor. I just finished a smaller ...
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Why is the electric dipole moment of the nucleus of an atom equal zero? [duplicate]

I read about the hyperfine interactions which cause the altering of the energy levels of the nuclues of an atom. Under the discussion about the electric monopole and quadrupole interactions, the term ...
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2answers
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Is there any full Compton scattering experiment done with x-ray since 1923?

The original paper of A.H.Compton 1923 did not provide data of a full experiment; he provided 3 points. Was his result corroborated by others? Can someone provide a real full set of data for Compton ...
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1answer
24 views

Released energy in a reaction

I'm having some trouble in understanding how the released energy in a nuclear reaction is actually calculated. I think I understand the general approach if we are dealing with a reaction like $$\rm ^{...
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Potential Energy Graph for Nuclear Force

when you draw PE energy graph wrt to distance between two interacting nucleons, at distance $r$ around 1 fm, graph has the lowest PE and is point of stable equilibrum. For $r >$ around 1fm, nuclear ...
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How are energies determined in gamma ray calibration standards?

In operating scintillation gamma ray detectors, certain gamma ray standards are used for calibration: Energy (KeV) Na-22, 511 Mn-54, 835 Co-57, 122 How are ...
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1answer
62 views

Why are all isotopes of tungsten considered (theoretically) unstable?

The Wkipedia article on tungsten says: Naturally occurring tungsten consists of four stable isotopes ($^{182}\mathrm W$, $^{183}\mathrm W$, $^{184}\mathrm W$, and $^{186}\mathrm W$) and one very ...
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How To Simulate Muon Induced Nuclear Fusion?

I am familiar with euler-lagrange equations which can be used to simulate a mechanical system, something like an inverted pendulum on a cart. How can I simulate a volume of deuterium and tritium with ...
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1answer
38 views

Positron beta decay in stellar core plasma

According to introduction level textbooks $\beta^+$ decay, that is conversion of protons into neutrons only occurs in atomic nuclei. $$p \xrightarrow{\beta^+} n + e^+ + \nu_e$$ I understand that it ...
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3D harmonic oscillator magic numbers

I know that, $$V(r) = (1/2) m \omega^2 r^2 ,$$ $$\omega \approx 40(Z+N)^{-1/3}\ \rm{MeV} $$ and $$E = (n+3/2) \hbar \omega.$$ How do you find the magic numbers of protons and neutrons which ...
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Threshold energy of Ti-48 inverse beta decay

Goal: Use anti neutrinos to convert Ti-48 to Ca-48 using inverse beta decay (IBD). The resulting Ca-48 should have the same half-life as natural Ca-48. Question: What is the threshold energy for the ...
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2answers
80 views

High Flux Antineutrino Sources

I was curious if there were any anti neutrino sources with a similar flux to a nuclear reactor. My current purpose does not allow for a nuclear reactor, however, any flux source with a similar flux ...
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1answer
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Decay process of pions

$\pi^+$ and $\pi^-$ decay into muon(or electron) and neutrino and $\pi^0$ decays into photons. So there is a weak interaction in the decay process of $\pi^+$ and $\pi^-$. But the mean lifetime of $\...
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1answer
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Has many-body tunneling at the level of nuclei been studied?

In a recent paper, the authors stress the difference between single-body tunneling and many-body tunneling (at the atomic level): "In contrast to the well-studied incoherent single-particle tunnelling,...
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1answer
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Calculating binding energy from mass defect

I am trying to wrap my head around the relationship between binding energy and mass defect. I have read that the difference between the binding energies of the products and reactants of a nuclear ...
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1answer
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Photoelectric effect photon attenuation disctontinuities

Can anyone explain why there are the discontinuities in proximity of the electron energies? I was thinking : every time the photon gains enough energy to ionize a new and a more bounded electron there ...
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1answer
35 views

How to express the $Q$-value for alpha decay in terms of binding energy of the relevant species?

I have 2 questions regarding the solution to the following question: The solution states that: Mathematically, I understand how the end result $$Q=BE\left({}^{A-4}_{Z-2}\mathrm{Y}\right)+...
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2answers
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Do virtual mesons exchanged between nucleons in the nuclear force ever decay before reaching the recipient nucleon?

So my understanding of the nuclear force so far is this (please correct anything I have wrong): Being a residual of the strong force, the nuclear force is mediated (in part) by the emission of ...
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1answer
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Thermodynamics of early universe - proton and neutron ratio [duplicate]

So, I have been reading about connection of particle physics and thermodynamics of early universe. Like after big bang, and quark - gluon plasma etc.. Anyway, after 1 second after big bang, the ratio ...
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Plum-pudding atomic physics in higher dimensions?

It is established that "normal" electron orbitals are not stable in more than 3 spatial dimensions, as the available energy levels become unbounded from below. However, this result only applies given ...
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How does the weak interaction sense the instability of a nucleus?

To reduce the disruptive energy, the weak interaction allows the number of neutrons to exceed that of protons (...) (via nasa.gov). How did it know it needs to reduce the disruptive energy? Example: ...
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1answer
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What are the conditions for nuclear decay?

I read something about that the Q-Value hast to be greater then $0$. But there must be certainly more conditions otherwise there would be nuclei that could't decay.
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Asymmetry in p-p, n-n and n-p interactions

Why does the asymmetry exist between the proton-proton, neutron-neutron and neutron-proton strong interactions in the nucleus (which results in nuclei preferring equal numbers of neutrons and protons)?...
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How would a nuclear explosion really operate in outer space?

(Repost from RPG.SE, per the community's suggestion.) A friend recommended I post this question here - said I'd be more likely to get a useful response than, say, from Reddit. My question is: How ...
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1answer
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Magnitude of charge and mass from cloud chamber

I was reading the anderson original article on the discovery of the positron, but I can’t figure out how he estimated the charge and mass. The paper : https://journals.aps.org/pr/pdf/10.1103/PhysRev....
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Is it a coincidence that Big Bang nucleosynthesis lasted about one free neutron half-life?

The free neutron half-life is about 10 minutes. Big Bang nucleosynthesis, which mostly involves protons and neutrons interacting, lasted about 20 minutes. Question: Is it a coincidence that these ...
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In beta plus decay proton gets converted to neutron— where does the extra mass come from? [duplicate]

Beta plus decay seems to be violating law of conservation of mass-energy-- when a proton changes to neutron a very small quantity of Mass is added to the right side of equation -- but where does this ...
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1answer
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How to transform activity ratio to isotope ratio? [closed]

I am given a table that describes an ancient spillage of spent nuclear fuel: ...
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1answer
56 views

How to calculate the uncertainty of a fit function? [closed]

I'm doing research on nuclear physics. What I will be asking is actually some general question. Suppose that I have a set of data with 8 points x={x0,x2...,x7} (in my example, x-axis is transverse ...
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1answer
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Nuclear Reactivity of Water and Steam (Chernobyl)

Like many, I have become very interested in the Nuclear Disaster of Chernobyl, after the acclaimed mini-series. So I started digging around for more information. The series, of course, does not give ...
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1answer
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Beta decay of beryllium into boron: conservation of spin violated?

I found following reaction in my lecture: $$^{10}Be_{6} \rightarrow ^{10}B_5+e^{-}+\overline{\nu}_e$$ since Beryllium has an even number of protons and neutrons its nuclear spin is $0$. However, ...