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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26 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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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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42 views

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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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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1answer
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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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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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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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46 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
49 views

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, ...
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58 views

How long is spent nuclear fuel radioactive?

I'm trying to understand the nuclear waste problem, and I've read enough to know that even the 10,000 years that the Waste Isolation Pilot Plant is licensed for is far too short to eliminate the risk ...
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Usefulness of high molecular speeds in nuclear fusion reactions

How do molecules having speeds many times greater than mean speed help in making nuclear fusion reactions in a laboratory?
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Nuclear Reaction Conservation of Nucleons

I'm having a hard time trying to understand a nuclear reaction: $$_{2}^{1}\textrm{He} + {}_{3}^{6}\textrm{Li} \rightarrow {}_{\phantom0 5}^{10}\textrm{B} \rightarrow {}_{4}^{9}\textrm{Be} + {}_{1}^{...
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Can beta rays induce radioactivity

I am aware that alpha particle can induce radioactivity. Is it also true for beta and gamma rays?
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Is Inverse Beta Decay a way to “undo” beta decay?

If we consider the beta-minus decay of a radioisotope, we produce an electron and an antineutrino, and a neutron which is converted to a proton. Say we take this same isotope and shoot an ...
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0answers
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Wavefunction for the deuteron's ground state

I was reading Blatt & Weisskopf's Theoretical Nuclear Physics (1979) and on the II.Two-Body Problems at Low Energies chapter, page 100, they say: The wave function for the composite state (the ...
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1answer
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Why do the elements Tc and Pm have such low abundances?

What specific nuclear and electronic properties make these two elements (Tc & Pm) almost disappear from solar and galactic abundance tables?
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1answer
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Mott Scattering

I had this old homework that I never completely understood. A scatterng experiment is performed with electrons ($E_0=450$MeV) colliding at an atomic nucleus.Following form factor is measured $\left |F(...
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59 views

Rutherford Backscattering spectrometry [duplicate]

I recently read about Rutherford Backscattering spectrometry and stumbled upon following equation $$\frac{d\sigma}{d\Omega}=\left(\frac{Z_1Z_2e^2}{8\pi\epsilon_0mv_0^2}\right)^2\csc^4(\frac{\Theta}{2})...
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Neutron capture calculation

So, the problem state is: Neutron beam radiates sample A with initial number of atoms $N_0$. With neutron capture nuclei (cores) of A are transitioning to nuclei B (they are just one neutron richer ...
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1answer
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Producing a pair of pions

I know that two protons colliding at high energies can produce a pion $$p+p \rightarrow p+p+\pi^0$$ But is it possible for two protons to produce a pion pair? $$p+p \rightarrow p+p+\pi^{-}+\pi^{+}$$...
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Could the end cap of the Pascal B (1) survive its trip through the atmosphere?

In 1957, the US had a nuclear test where a shaft was dug 152 meters into the ground. A 100 mm thick, 900 kg steel plug was installed and welded at the top of the shaft. Under it was 2 feet of ...
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How can beta plus decay be possible?

$\beta +$ decay is where a proton gets turned into a neutron and a positron and a neutrino. However, a neutron is heavier than a proton, so obviously this reaction is endothermic. So then, why does ...
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Nuclear Physics Question

How could I calculate the chance of a proton actually joining the nucleus and 2 protons and 3 and so on? Assuming a large number of protons are fired at a substance?
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Baryon number conservation

Can someone explain me why the Hamiltonian for the nucleon field (derived from the corresponding Lagrangian) $$H_N=\int d^3xN^\dagger(\textbf{x})\Big(-\frac{\nabla^2}{2M_0}+M_0\Big)N(\textbf{x})$$ ...
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Intermediate product of CNO cycle

CNO cycle of stellar nucleosynthesis involves several steps in which different isotopes of Carbon, Nitrogen, and Oxygen are transmuted into each other when hit by a ...
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Ground state of an odd, deformed nucleus: intuition for what happens to the $j_x$ and $j_y$ of the odd particle

This is something that relates closely to my long-ago PhD research, and it's a point that I never satisfied myself thoroughly on. I have a copy of a standard text that covers this general topic, de ...
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Understanding the Level scheme of a nucleus from Nuclear Data Base

Sorry If this Question is not eligible to be posted here. Nuclear database shows observed nuclear electronic energy levels of $O^{17}$ having neutron separation energy 4143 keV. I want to find ...
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4answers
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Does a proton have a binding energy?

When calculating the $Q$-value, $Q = \Delta M \cdot c^2$, of this reaction: $$ ^6Li \ (\alpha, p)\ ^9Be \quad \iff \quad \alpha + \ ^6Li \ \longrightarrow \ ^9Be + p $$ The $Q$-value can also be ...
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Shell model label symmetry

I'm working through the quark model Hadron wavefunctions, and trying to figure out the flavour-spin part of the wave functions. This is easy enough for S shell spatial states, since the space wave ...
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1answer
94 views

Is this a radioactive meteorite? [closed]

Can a neutron beam emission from a strong naturally-occurring radioisotope deflect a small sewing needle hung by a thread an inch from the source? I have someone reporting to me of such a thing ...
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1answer
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Trinity vs Nagasaki

From what I read the radiation levels in Nagasaki today are equivalent to the natural background radiation levels in the surrounding areas. On the other hand, the radiation levels at the Trinity test ...
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1answer
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Shell Model of the Nucleus Holes

Can someone help me how to determine whether there is a hole or a particle in a given shell? Is it as simple as if the number of particles is close to the number of the maximum particles in each shell,...
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1answer
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Why doesn't a deuterium-deuterium reaction usually yield Helium-4?

I assume the above reaction is less energetically favorable than the creation of He-3 (plus a neutron) or tritium plus a proton? But why/how? Or are the hard, hot, fast collisions too much for it to ...
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How exactly did lowering of the graphite parts of the control rods on Chernobyl's RBMK reactor result in reactivity surge?

There are many sources giving different data on the initial position and the dimensions of the rods, but most suggest that the absorber was located just outside the core when AZ-5 was pressed, and the ...
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1answer
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How does the strong interaction “create” the nuclear force?

I’ve recently read that the strong interaction, that holds the quarks together to form protons and neutrons, also creates a residual force called the nuclear force, which holds the neutrons and ...
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1answer
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Direction of neutron scattering

When neutrons interact with matter scattering, what direction to they scatter? Is it random, or some probability distribution of directions? I'm trying to understand why neutron reflectors reflect ...
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1answer
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Why does fusion above nickel 56 require energy?

I've always struggled with the concept of fission and fusion. I mean I can show a mass deficit with math easily enough but I have always struggled understanding the fundamental concept of why things ...
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How does heat is generated during nuclear reaction

In a nuclear reaction 235-U is being constantly divided under high neutron flux. After the division we get 2-3 neutrons with high energy and fission products with its own energy. My question is from ...
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Is fission/fusion to iron the most efficient way to convert mass to energy?

Is fission/fusion of any element to iron-56 (or nickel-62?) the best way to convert mass to energy, that doesn't involve black holes? In other words, will we be always limited to convert only about 1%...
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1answer
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Irradiated persons as sources of radiation?

The new HBO series "Chernobyl" is supposedly filled with misconceptions about radioactivity, among other things, according to an opinion piece published in "Forbes". In particular: "The most ...
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2answers
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Why don't we coat the pressure vessels of nuclear reactors in boron to reduce neutron embrittlement?

Neutron embrittlement is a big problem in reactor design, as high energy neutrons cause lattice defects in materials like steel by slamming into iron nuclei. This limits the lifetime of the reactor, ...
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What was the vertical beam of light in Chernobyl?

In the HBO miniseries Chernobyl after the initial explosion we see a clear bright light shooting vertically up from the plant. I presume this was a thing that actually happened and not some creative ...
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Did the Chernobyl power station's water cistern really hold $7000\:\rm m^3$? [closed]

In he HBO TV miniseries Chernobyl, they talk about a cistern holding 7000 cubic meters of water. That is the content of Loch Ness, the deepest lake in the UK. Would the Chernobyl reactor really hold ...