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

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What has $E = mc^2$ to do with nuclear powerplants?

In life, when you talk about nuclear energy, there always happens to be a guy who says that famous Einstein's equation. "Yeah, they just convert mass to energy, $E = mc^2$ ya know?" When I think ...
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295 views

Proton mass and Weizsäcker's formula

I'm so confused in the use of nuclear masses and atomic masses. I have two questions. From the book "Outline of Modern Physics" by Ronald, I understand that the semiempirical mass formula ...
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1answer
109 views

One body harmonic oscillator states expressed in terms of creation operators

I am reading trough chapter one of Moshinsky's "The harmonic Oscillator in Modern Physics". However i am having some trouble with the mathematics in section 8 of chapter 1. I will sketch a summary of ...
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2k views

Can open, unsafe nuclear fusion reaction burn the atmosphere?

I happened to hear people saying that the nuclear fusion bomb tests could set the atmosphere on fire. I have some serious doubts about that - but I have no facts. Nuclear fusion reaction requires ...
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143 views

What's gonna happen if a nuclear bomb explodes nearby? [closed]

I live in the capital, 10 km from its center on the 9th floor, my windows facing the opposite direction will I still see a flash? Will I hear something? How loud will it be? How fast would I die? If I ...
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613 views

Why is Helium-3 better than Deuterium

I see that many websites and magazines with physics thematic are pretty excited about mining Helium 3 isotope on the Moon. But this seems to be a very hard-to-get resource. For more than one reason: ...
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107 views

Harmlessness of a pure alpha decay particle

From my high school physics class I remember that there are some particles which exhibit pure alpha decay (i.e. alpha decay to there stable isotope), like Po-210, Po-211 and Bi-209. What I also know ...
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160 views

$Q$-value in nuclear reaction $^{9}Be\left(\gamma,n\right)^{8}Be$

I have two questions. First, I understand that in a nuclear reaction $$Q:=K_{after}-K_{before}\equiv E_{0,before}-E_{0,after} \qquad (1)$$ where $K$ is the total kinetic energy, and $E_0$ is the ...
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67 views

Calculate energy from an reaction [closed]

I'm trying to calculate the released energy from a reaction. The radioactive substance polonium decays according to this formula: $$^{210}_{84}\mbox{Po} \rightarrow \mbox{X}+^4_{2}\mbox{He} $$ At ...
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428 views

Stable Nuclei - Deviation from equal protons and neutrons

While studying the semi-empirical mass formula for nuclei, I came across an "asymmetry term" whose function, as far as I understand, is to build in the fact that nuclei "prefer" to have equal numbers ...
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241 views

Electric potential energy after nuclear fission

We have a uranium-236 nucleus that fissions into two equal fragments, and I'm supposed to find the electrical potential energy just as the two fragments split apart. No other information is provided. ...
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110 views

Uncertainty Principle on System of particles

I am new to Quantum Mechanics. I read the uncertainty principle - it says there are pairs of physical quantities which can't both be determined with certainty for a particle. My question is does the ...
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315 views

what is the magnetic quadrupole operator?

To find magnetic or electrical moments in quantum theory we must calculate the expectation value of an appropriate operator. the dipoles operator are similar and is easy to find but the magnetic ...
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300 views

What is the magnetic quadrupole moment of a nucleus in cylindrical coordinates?

What is the magnetic quadruple moment of a nuclei in cylindrical coordinates? The quadrupole moment of a nucleus is zero in spherical coordinates but in the cylindrical coordinates it can't be ...
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3answers
26k views

Why can Hiroshima be inhabited when Chernobyl cannot?

There was an atomic bomb dropped in Hiroshima, but today there are residents in Hiroshima. However, in Chernobyl, where there was a nuclear reactor meltdown, there are no residents living today (or ...
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76 views

Finding radioactive nucleus given table of values

Question Measuring the number of decays per minute $N(t)$ of a radioactive source every four days we have that: $N(t=0):=N_0=200$, $N(t=4)=141$, $N(t=8)=100$, $N(t=12)=71$, where $t$ is measured in ...
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109 views

Containement system of a nuclear reactor: role of the water moderator

In a modern nuclear reactor for example a PWR there are multiple containment systems which prevent the release of radioactive material into the environment and shield the environment from the ...
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1answer
412 views

Speed of neutrons in a nuclear reactor

How fast (in $\frac{\mathrm{m}}{\mathrm{s}}$) are typical neutrons before and after slowing down in a nuclear reactor (with U-235 and $H_2O$ as moderator)? Do you have any reference for the values?
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888 views

Adding many more neutrons to a nucleus decreases stability?

If you take any large nucleus and add protons to it, the electrostatic repulsion between them will make the nucleus more unstable, because the electrostatic force between them is more repulsive at a ...
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239 views

Radioactive Decay

Problem:Nuclei of a radioactive element $\Bbb X$ having decay constant $\lambda$ , ( decays into another stable nuclei $\Bbb Y$ ) is being produced by some external process at a constant rate ...
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337 views

Should the expression for energy conservation in alpha decay include the mass of electrons?

Let $M_P$, $M_d$, $m_\alpha$, $m_e$ and $Q$ the mass of the parent nucleus, daughter nucleus, alpha particle, electron and the disintegration energy, respectively. I understand that applying ...
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3answers
799 views

What stabilizes neutrons against beta decay in a neutron star?

Free neutrons are known to undergo beta decay with a half-life of slightly above 10 minutes. Binding with other nucleons stabilizes the neutrons in an atomic nucleus, but only if the fraction of ...
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218 views

Energy conservation in nuclear reactions and radiactive decay

Reading "Fundamentals of Nuclear Physics" by Atam P. Arya, I understand that in a nuclear reaction, let say $x+X \to y+Y$ meaning that "when a particle $x$ strikes a target nucleus $X$, the outcome of ...
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150 views

Why is a pion so light compared to a neutron or proton?

A pion is made out of a pair of up and/or down quarks. A neutron or proton is three up or down quarks. So naively I'd expect a pion to be about 2/3 the mass of a nucleon. In fact it's less than 1/6 ...
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What is the lowest possible theoretical temperature that nuclear fusion can occur at?

I am not talking about the pseudo-science of so called cold fusion I am interested in what temperature you can get away with to produce fusion reaction. I was thinking in terms of micro-fusion or at ...
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74 views

Interaction photons-matter and dimensional analysis

I know that when photons pass through matter, the law that describes the intensity in function of the thickness is: $$I(x)=I_0 e^{-\mu x}$$ where $\mu = \rho \frac{N_a}{A} \sigma$ and ...
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921 views

Alpha particle and helium nucleus

The symbol for the alpha particle is α or $α^{2+}$, it can be written as $He^{2+}$. What I want to know is that, are they same? I mean alpha particle and helium nucleus are same or any subtle ...
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586 views

Ratio of Size of Atom to Size of Nucleus

I have the following problem: In nuclei, nucleons exists in nuclear energy levels and in atoms, electrons exist in atomic energy levels. The order of magnitude of nuclear energy is 1MeV whereas ...
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179 views

$\require{mhchem}$ $\ce{\beta^{+}}$ decay for $\ce{_9^18F}$, computing $\Delta m$

For the decay: $$\require{mhchem}\ce{_9^18F\to_8^18O +e+ +{v}}$$ To compute $E$, I need $\Delta m$, the provided answer looks like: $$m_i = 18.000938~u$$ $$m_f = 17.999159~u + 2~(5.49 \times ...
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388 views

Why are alpha particles such a prominent form of radiation and not other types of nucleon arrangement?

It is said in many textbooks that alpha decay involves emitting alpha particles, which are very stable. Indeed, the binding energy (~28.3 MeV) is higher than for $Z$-neighboring stable isotopes. But ...
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296 views

Bremsstrahlung: why is electron slowed/stopped by the positive nucleus?

I can't understand why the electron is slowed/stopped by the nucleus. The electron is a negative charge and the nucleus is positive... they should attract each other...
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132 views

Is speed of electrons in atoms a constant during explosions? [closed]

E.g. in exploding nuclear bomb or some other big explosions. I mean if the speed of electrons as waves/particles is a constant or changes according to other "forces" involved?
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252 views

We're all star dust?

OK so we've all heard of this from Carl Sagan, Lawrence Krauss and others and we know the argumentation, I don't refute that. There are other examples, for instance I once calculated (this was before ...
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Does quark color contribute to “spin degeneracy” for QGP calculations?

Like the title say, does quark color matter in counting contributions in a early universe plasma (QGP), as when adding up the total plasma energy density, or is it just spin? The book I have (Pathria) ...
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701 views

Mass defect- From where mass is being lost?

As a school student, I have wondered while studying mass defect the following mysterious problem My assumption Just like a car's mass is constituted by each part of it(i.e total mass of car will be ...
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1answer
172 views

Ground states in the shell model for odd-even nuclei

I understand that even-even nuclei (Z and N number) have zero spin because of pairing. Even-odd nuclei have the spin of the odd nucleon, and parity is given by $(-1)^L$ - so my question is, ...
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1answer
289 views

Why is the total interaction cross section larger for incident particles with lower energy?

The cross section of a nuclear interaction is a measurement of the probability of that interaction occuring. These probabilities are typically presented in terms of barns ($10^{-28}$ m$^2$) as a ...
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1answer
52 views

Why did Otto Hahn use neutrons to generate transuranium?

In physics textbooks with chapters about nuclear fission there is often a historical introduction about Otto Hahn. That he tried to generate transuranium but discovered the nuclear fission. If you ...
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309 views

Calculate/estimate power of a fission bomb

I have some questions about the released energy and power of a nuclear fission bomb. What are the key dependencies of the power of a fission bomb? Is it true that the power of a fission bomb depends ...
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1answer
290 views

How to superimpose Wood-Saxon and Coulomb potential?

I have just written a simple simulation that models the tunnel-effect of alpha-particles for $^{212}$Po and $^{238}$Ur. In this simulation, I approximate the potential of the nucleus by a simple ...
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1answer
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Kinetic energy of alpha-particle in $^{212}$Po decay

Admittedly, Nuclear Physics is not my strength. I'm writing a simulation to model alpha-decay. So far, I have looked up the values of the kinetic energy of the alpha particles that are emitted in a ...
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2answers
217 views

What is the difference between the KDEMO and DEMO projects?

I'm writing a paper on the future of fusion technology and I can't seem to find the difference between Europe's DEMO experiment and Korea's KDEMO except for the fact that they are both planned to ...
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108 views

Can an Anti nuclear atom be synthesised so it can neutralise the effect of nuclear atom [closed]

as we have studied that if the number of electron becomes equal to number of proton then that particle becomes neutral. so what will the energy or procedure required to break the chain reaction in ...
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662 views

What does the Atomic Form Factor means?

I was reading about Nuclear Physics and the autor mentioned something about the Atomic form factor, something relationated with the Fourier Transform of the espacial distribution of the electric ...
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70 views

What fraction of nuclear excited states are known?

I was reading a paper today claiming observation of a new $2^+$ state in $^{12}\mbox{C}$, which would correspond to a sort of rotationally excited Hoyle state. Looking at NuDat reveals that this ...
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1answer
87 views

Developments originating from $E=mc^2$

What kind of significant impacts have originated from $E=mc^2$. Generally, it is regarded as the most famous equation of all time. Except for nuclear energy (fission and fusion) I do not know any ...
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249 views

nuclear fission and half life

Why is the alpha, beta or gamma decay of an unstable nucleus unaffected by the chemical situation of an atom, such as the nature of the molecule or solid in which it is bound? The chemical situation ...
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2k views

Can the solar system really fit in a thimble?

Almost every time somebody talks about atoms, at some point they mention something like this: If we remove the spaces between the atoms and atomic components, we can fit the solar system in a ...
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70 views

Nuclear transition notation

I have a question which asks me to determine what x is for the following nuclear transition $$^{29}Si(\alpha, n)X$$ But I don't have any idea what this notation implies. Another example: ...
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265 views

Coulomb barrier and proton evaporation

Why is it that neutrons evaporate from nuclei more easily than protons do? Intuitively, since protons are electrostatically repelled (in addition to whatever nuclear forces they have in common with ...