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

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Why is Helium-3 better than Deuterium for fusion energy production?

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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0answers
15 views

How to calculate exposure of beta and alpha decay

Is there a way to calculate exposure in roentgen from activity of from q-values? I currently have the activity of a beta decay in mCi over a certain amount of time and the total amount of energy, ...
3
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1answer
73 views

What is the physical meaning of the parameter of a Poisson distribution?

I have done a laboratory session at my university where I had to check that the disintegration of nucleii follows a Poisson distribution $$P(n)=\frac{\lambda^n}{n!} e^{-\lambda},$$ where $P(n)$ is ...
2
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0answers
22 views

What is the root mean square energy?

How the root mean square energy of nucleon in a nucleous of atomic number A in ground state is depend on A ?
7
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103 views

If there are long-lived elements in the Island of stability, why are they not present in Nature?

To my understanding, some (but not many) physicists speculate that the Island of stability may contain long-lived elements, as in a billion or so years. But couldn't we rule that out just by the ...
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1answer
1k views

What do we know about the interactions between the protons and neutrons in a nucleus?

In a nucleus, the strong nuclear force causes interactions between protons and protons, between neutrons and neutrons, and between protons and neutrons. What do we know about this interaction? ...
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Protons' repulsion within a nucleus

Do the protons inside the nucleus repel each other by the electrostatic force? If they do, why doesn't the repulsion drive the protons apart so that the nuclei get disintegrated?
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2answers
2k views

What makes a nucleus unstable?

My question is simply that - what makes a nucleus unstable? What exactly causes a nucleus to start breaking apart in the first place? Is it the Coulomb force between the neighboring protons? I'm just ...
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1answer
38 views

Why don't the nucleus break apart? [duplicate]

The nucleus of an atom is made up of protons and neutrons. So if there are many protons inside nucleus even though there are neutrons why don't this protons may repel away breaking nucleus apart? The ...
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1answer
29 views

Which is larger, all known, bound nuclear energy levels, or known, bound atomic energy levels?

Both the atomic nucleus and the electrons are (complex) quantum systems and have large numbers of energy levels and transitions, and a basic shell model is usually part of introductory atomic physics ...
6
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1answer
70 views

Charge structure of the neutron

David Griffiths’ book on elementary particles says that the neutron is positive at the center and edges, negative in between. (Introduction to Elementary Particles, Wiley, 1987, p. 21). But Wikipedia ...
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0answers
32 views

Why are parallel spins energetically favorable for nucleons? [duplicate]

For deuterium, both the proton and neutron preferentially occupy $1s_{1/2}$ orbitals which have orbital angular momentum $l=0$ and spin $s=1/2$. By coupling their orbital and spin angular momenta for ...
16
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2answers
267 views

In the Iranian nuclear deal, how can IAEA detect nuclear activity after 24 days?

This is a question related to current events, but I want to ask about the physics, which are not explained in any news article that I can find. Ernest Moniz and John Kerry wrote an op-ed in the ...
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2answers
330 views

$\alpha$ and $\beta$-decay, why don't they neutralize each other?

$\alpha$ radiation consist of positive charged helium nuclei, $\beta$ radiation of negative charged electrons. So why don't the $\alpha$ particles take those electrons to get neutral?
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2answers
55 views

Basics questions about the strong force

I have what is probably a bitter misconception about the strong force which I would like to clarify. Here's my (probably flawed) reasoning. The strong forces holds protons and neutrons together at ...
0
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0answers
17 views

Proportion of gamma rays in radioactivity from spent nuclear fuel [on hold]

In a Pressurised Water Reactor, a certain amount of radioactive waste is produced. Over a period of many years, often decades, it decays to give off alpha, beta and gamma rays. What proportion of this ...
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0answers
27 views

At what density and conditions would Californium-251 reach a supercritical mass? [closed]

If I were to obtain a sample of Californium-251 that weighs 1mg, how would I make that sample reach a supercritical state at which it would create a cataclysmic nuclear detonation? In a sphere, at -...
4
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1answer
48 views

Why alpha decay usually leads to ground state while beta decay usually leads to excited state?

When alpha decay happens the daughter nucleus is usually in ground state. When beta decay happens the daughter nucleus is usually in excited state which is then de-excited by emitting gamma photon. ...
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0answers
14 views

Can the energies released during different oxygen fusion reactions be averaged?

I am conducting an investigation regarding the ideal fuel for a star of 25 solar masses In terms of how much energy is produced.I have calculated each of the binding energies involved and then ...
0
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1answer
45 views

Can free particle (eg. unbound electron or proton) have angular momentum other than spin?

I am learning about parity of nucleus and (elementary) particles. For example, proton has a intrinsic parity of $+1$. However, a more general term for parity of proton is $(-1)^l$ where $l$ is orbital ...
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2answers
28 views

Gamma spectroscopy - Nuclide identification

I have a question about what the usual practice is for nuclide identification in gamma spectroscopy. For example, if I see a line at 477 keV, I would write that the origin of this line is $^7Be$. As ...
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1answer
43 views

What is the spectrum of a nuclear bomb in a vacuum?

This question about 'nukes in space' mentions that the two forms of energy released from a nuclear bomb come from neutrons and photons (the latter about 104 times the former). It's mentioned that the ...
0
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2answers
73 views

What is an element's “weight” when talking about “elements heavier than iron” being formed in supernovae

I always hear that elements heavier than iron are formed in supernovae. But, what is taken as an element's weight? I had always believed that this meant any elements with an atomic number greater than ...
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2answers
22 views

Nuclear physics study materials

I'm currently a ChemE undergraduate student and wish to pursue masters in nuclear engineering. Can you suggest some introductory reading material so that I can get acquainted with nuclear engineering ...
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1answer
145 views

Nuclear explosion wavelength data

I am looking for data source (or chart) of spectral data that is being emitted on detonation of nuclear or thermonuclear explosion. Reason I am looking is to see if this data has specific signature ...
19
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3answers
1k views

Why can't a nucleus become a black hole?

A nucleus is very small and very dense. Its density is approximately $2.3 \times 10^{17}~\mathrm{kg/m^3}.$ So why can't a nucleus itself become a black hole?
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4answers
242 views

Can we predict the half-lives of radioactive isotopes from theory?

Is there any way to predict the half-lives of radioactive isotopes from theory (that is, using only theoretical considerations, without using data about the decay)? For example, could we predict that ...
3
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2answers
53 views

What is W.u. as a unit in a nuclear physics context?

In a recent paper (doi/arXiv), of note for causing this recent tussle over its handling by science news media, there's some strange units I can't quite puzzle out. Specifically, the abstract contains ...
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1answer
54 views

How can alpha or beta emission maintain equal numbers of protons and electrons? [duplicate]

In radioactivity we know that a parent nucleus can disintegrate into daughter nuclei by emitting alpha or beta particles. If this is true then how can the daughter nucleus have as many electrons as ...
46
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3answers
6k views

Do pear-shaped nuclei really have anything to do with time travel?

Recently (in the last week or two), various articles about pear shaped nuclei have appeared, such as this one from Science Alert and this from the BBC The Science Alert article includes the quote ...
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2answers
78 views

Left radioactivity in Hiroshima and Nagasaki [closed]

What is the level of the left radioactivity in Hiroshima and Nagasaki? It seems that people there live very well. So, the radioactivity is very low?
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2answers
46 views

Is critical mass of fissile material the same in gravitational fields with different force?

Let's take plutonium-239 for example. $10\, Kg$ (sphere $9.9\, cm$) need for a nuclear reaction. Are we talking about these numbers in Earth environment with $\approx 9.8\, m/s^2$ gravitational ...
1
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1answer
46 views

Why is Helium an anomaly on the binding energy curve?

So I'm failing to understand why helium is anomalous on the binding energy curve. I know it includes concepts such as pairing, shell correction, and the liquid drop model. However, these were simply ...
0
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1answer
162 views

Nuclear to Electricity Energy Conversion

Currently nuclear power generates heat, which heats water into steam that turns conventional turbines. The energy conversion is as follows: photonic->heat->kinetic->electric This would result in low ...
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2answers
46 views

Half life and Radioactive Decay

[Sorry about the misleading title, as the query isn't entirely about half-life, but I couldn't find any better way to condense my question to make a brief enough title anyways..... and] Radioactive ...
8
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3answers
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Would being underwater help survive a nuclear bomb?

If I jump in my pool, on the river near my house knowing that a nuclear bomb, or atomic or H-Bomb exploded around 10 km from my house, would I survive? The way I see it is that water will protect me ...
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1answer
23 views

An approximation question from “Nuclear Models” by Judah Eisenberg and Walter Greiner

I'm looking at page 311 of the book "Nuclear Theory" by Judah Eisenberg and Walter Greiner. Now for identity (49) which is: $$\omega_{1,2}^2=\frac{\omega_\alpha^2+\omega_\zeta^2-2bc\omega_\alpha\...
3
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1answer
73 views

Where does the $0.61$ come from in $ R \sin \theta = 0.61\lambda $?

In my A2 Physics textbook it says that In the estimation of the nuclear radius by using electron diffraction the equation $$ R \sin \theta = 0.61\lambda $$ where: $R$ = radius of the nucleus $\...
4
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2answers
37 views

How to calculate absorbed dosage

Lets say you have some unstable isotope which decays via beta decay. For example, lets say you want to calculate the amount of beta radiation that is emitted from the decay of $^{87}\textrm{Kr}\to ^{...
4
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2answers
773 views

What causes Potassium to decay into Argon the way it does

From evolutionwiki: "Potassium 40 decays into argon 40 through a process known as electron capture. In electron capture, an electron from the innermost electron shell "falls" into the nucleus, ...
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0answers
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Have the BaF2 scintillators a strong correlation with the alimentation current that cause the shifting of the centroids in the distribution?

In gamma gamma correlation I suspect the presence of systematic error maybe caused by a non optimal alimentation voltage according to someone there is a quadratic correlation between centroids ...
1
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1answer
37 views

How is the amount of radiation calculated from a decay?

Lets say you have some unstable isotope which decays via beta decay. For example, lets say you want to calculate the amount of beta radiation that is emitted from the decay of $^{87}\textrm{Kr}\to ^{...
2
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1answer
45 views

C-parity violation evidence

I know about the CP-violation experiments from the 60's and the P-violation from the 50's. But, is there a similar experiment which displays (perhaps historically in the same way as the experiements ...
2
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1answer
40 views

propagation of error - sin^4

I am currently working on an analysis of a Rutherford scattering and encountered a somehow strange behaviour for the errors. It basically boils down to the behaviour of: $$\sin(\theta/2)^4$$ For ...
3
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1answer
57 views

Forbidden transition

My question concerns something I just read on wikipedia whilst looking up forbidden transitions, here: https://en.wikipedia.org/wiki/Forbidden_mechanism#Gamma_decay Specifically, this sentence: "...
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0answers
46 views

Derivation of Critical Mass of U-235

I am having trouble following an explanation of the critical mass of U-235 from my book (for high school physics). First off, every chain reaction of U-235 releases on average $\nu = 2.42$ neutrons. ...
0
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2answers
76 views

The counter-intuitive time scales in atomic physics and nuclear physics

Compare atomic physics and nuclear physics. The interaction in the latter is much stronger than that in the former. However, the typical spontaneous emission time scale in atomic physics is on the ...
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0answers
33 views

Model for obtaining the magnetic moment of a neutron [closed]

The anomalous magnetic moment of a neutron ($g_s=-3.83$) could be considered as a fixed proton ($g_s=5.58$) with an orbiting $\pi⁻$ meson in an $l=1$ state. a) What is the magnetic dipole moment of ...
6
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2answers
3k views

Effect of temperature on radioactivity?

I'm researching the effect of temperature on uranium radioactivity, however I can't find any solid empirical evidence to prove the notion that temperature does not affect radioactivity. Can anyone ...
19
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3answers
983 views

Long time deviations from exponential decay in radioactivity

Are there any examples of common substances whose decay is not exponential? We're used to thinking about radioactivity in terms of half-lives. This is a concept that makes sense only for a decay that ...