Nuclear physics is the study of the composition, behavior and interaction of atomic nuclei and their constituent parts.
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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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2answers
25 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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29 views
The Hartree solution of two harmonic oscillator coupled by potential $V \propto ({\bf r}_1-{\bf r}_2)^2$ [closed]
$H={\bf p}_1^2+{\bf p}_2^2+{\bf r}_1^2+{\bf r}_2^2+x({\bf r}_1-{\bf r}_2)^2$.
$x$ is the coupling factor.
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20 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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1answer
29 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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1answer
438 views
Why can Hiroshima be inhabited when Chernobyl cannot?
In Hiroshima, atomic bomb was dropped, but today, there are residents in Hiroshima. However, in Chernobyl, there is no resident living today (or very few). What made the difference?
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37 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
776 views
Does the Breit Wigner formula apply to intermediate virtual particles?
Breit Wigner Formula describes the cross section for interactions that proceed dominantly via a intermediate particle (O*) A+B → O* → C + D:
$$σ = \frac{2\Pi}{k^{2}}\frac{Γ_{i}Γ_{f}}{(E-E_{o})^{2} + ...
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2answers
34 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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28 views
Approximately how much would a LFTR cost? [closed]
Would anyone happen to know how a LFTR costs?
Please could you include the efficiency and payback time.
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1answer
36 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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1answer
39 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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2answers
121 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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1answer
121 views
How was Be-8's Half-Life of 7E-17 Second Determined?
Radionuclides occur with half-lives in a vast range of over 37 magnitudes as listed in this site. In question 7584, Lubos Motl explained how Gyr half-lives were determined. This method doesn't appear ...
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2answers
143 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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1answer
100 views
Why is the Wick contraction in HFB or BCS equal to a single-particle density?
I'm trying to understand how in Hartree-Fock-Bogoliubov
(HFB) or BCS theory we can write a product of creation/annihilation operators as single-particle densities under the guise of "Wick's theorem".
...
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39 views
Find mass of Plutonium in alpha decay [closed]
I did:
$$\Delta mc^2 = (m_{Pu}+m_{U}+m_{He})c^2$$
$$\frac{5.24 \times 10^6 eV}{(3 \times 10^8)^2} = m_{Pu} + 235.043924 + 4.002603$$
$$m_{Pu} = 239.0465$$
But answer is 239.052157, slightly ...
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2answers
121 views
What stabilizes neutorns 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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1answer
35 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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1answer
127 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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1answer
61 views
Which pion is mediator in nucleon-nucleon interaction
In nucleon-nucleon interactions of n-n, p-p, n-p how do you determine which pion is the mediator?
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1answer
283 views
Why the pion does not get mass under Spontaneus breaking of chiral symmetry, but the quarks do?
Some sources state that when the mass of a quark goes to zero, it allows for Spontaneous Breaking of Chiral Symmetry and gets a constituent mass of about $200\, \mathrm{MeV}$.
Other sources state ...
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1answer
74 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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1answer
73 views
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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1answer
69 views
Does the strong (nuclear) force ever contribute to decay?
Does the strong (nuclear) force ever contribute to decay ?
Or is the weak nuclear force the only decaying force ?
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3answers
37 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}$$
where $\mu = \rho \frac{N_a}{A} \sigma$ and ...
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2answers
79 views
Coulomb barrier and proton evaporation
Why is it that neutrons evaporate from nuclei more easily than protons do?
Intuitively, since protons are electrostatically repelled (in addition to whatever nuclear forces they have in common with ...
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1answer
344 views
Is ultradense deuterium real?
I've found several articles discussing experimental evidence of a deuterium state of densities over $140 \textrm{ kg}/\textrm{cm}^3$:
F. Winterberg. Ultradense Deuterium. arXiv.
Shahriar Badiei, ...
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2answers
64 views
Alpha particle and helium nucleus
The symbol for the alpha particle is α or $α^{2+}$, it can be written as $He^{2+}$.
What I want to know is that, are they same? I mean alpha particle and helium nucleus are same or any subtle ...
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1answer
63 views
Ratio of Size of Atom to Size of Nucleus
I have the following problem:
In nuclei, nucleons exists in nuclear energy levels and in atoms, electrons exist in atomic energy levels. The order of magnitude of nuclear energy is 1MeV whereas ...
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1answer
182 views
How is it possible to calculate the energy liberated by a given fission process?
How is it possible to calculate the energy liberated by a given fission process? For example, in the fission of a $^{235}$U induced by capturing a neutron?
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1answer
53 views
$\require{mhchem}$ $\ce{\beta^{+}}$ decay for $\ce{_9^18F}$, computing $\Delta m$
For the decay:
$$\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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4answers
174 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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2answers
68 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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1answer
66 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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3answers
215 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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64 views
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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2answers
129 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
40 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, ...
3
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1answer
107 views
Gamma Ray LASER Theory and Technology
I am aware that a similar question has been asked by someone else in the past, but in a very general form. Due to the physics interest and technology, in this question I put emphasis on the detail of ...
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1answer
121 views
How do people get the proton number for each element from experiment?
How did people determine the proton number for each element from experiment in each decade of 20th century?
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1answer
57 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
62 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
76 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 ...
2
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1answer
40 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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1answer
283 views
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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0answers
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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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1answer
61 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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225 views
Difference between Nuclear Bomb and Atomic Bomb? [closed]
What's the difference between the Nuclear Bomb and the Atomic Bomb? Or are they necessarily the same thing?
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1answer
49 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 ...
