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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Beryllium Neutron Multiplier

We know that Beryllium is used in blankets of Fusion Systems because it is a neutron multiplier. I was wondering that if Beryllium is a neutron multiplier can it be used in the fission process(of ...
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What if free proton decays? [closed]

what if think for a second that in actual scenario free proton decay in the universe? Would it effect much in our daily life?
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Can nuclear spin interactions drive nuclear transitions?

The atomic nucleus is often treated as monolithic from the perspective of atoms and molecules, but NMR demonstrates that nuclear states can be affected through external means. Especially the ...
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How can I find the half-life of these? [closed]

Curium $^{250}\text{Cm}$ is the lightest nuclide to undergo spontaneous fission as the main decay mode. Analyze this decay mode following the same theory we saw for alpha emission and in particular ...
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Alpha emission of U-238

Alpha emission paradox says that an alpha particle with energy ~4 MeV is able to "come out" of the nucleus of U-238 but an alpha particle of energy ~9 MeV is unable to penetrate the Coulomb barrier of ...
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How do I occupy energy level by proton and neutron? [closed]

Estimate the $^{27}A$l nucleus as a rigid hollow sphere, list all of the occupied energy levels by protons and neutrons inside the sphere. I'm not sure that this problem can represent as Fermi ...
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Effective Field Theory [closed]

All my efforts to understand what is going on in this diagram were unsuccessful. Could someone kindly help me with the proper explanation of what these diagrams mean and what is going on in the ...
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1answer
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Cross-section uncertainty of $^{56} Fe$ and $^{1}H$

I was reading Laura Clouvel 's thesis on Uncertainty in fast neutronic flux. In this document, Hydrogen and Iron seem to be the main source of uncertainty in a PWR reactor. Intuitively, I would have ...
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Can electrons combine with neutrons to form negatively charged nuclei?

I've been wondering if electrons and protons could switch place such as constituent of an atom nuclei or that a proton "orbits" an electron instead ("inverted" hydrogen), are there forces on the quark ...
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Is spin-orbit coupling mass dependent?

When comparing spin-orbit coupling in the case of electrons and in the case of nucleons, do nuclear states exhibit a stronger level splitting compared to atomic states because the nucleons are more ...
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What is the extreme long-term elemental composition of the universe?

In Freeman Dyson's classic 1979 Time Without End paper he points out that, if proton decay does not occur, then normal matter will spontaneously fuse to iron on a timescale of $10^{1500}$ years, and ...
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In fusion inside stars (sun) or very hot gasses, how do the electrons get bound and what about tritons and D-T vs D-D fusion?

Most texts I've read focus on just the nuclei to begin with, but eventually start talking about Helium (or other) atoms and isotopes. A few aspects aren't clear to me and I'd be grateful for some ...
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Why did the Baker Shot have a normal mushroom cloud instead of a radial blast wave?

The US tested its first underwater nuclear device with the Baker Shot in Bikini lagoon. It was supposed to be identical to the Fat Man device dropped on Japan. However it was measured at 23 kt ...
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Nuclear binding energy and mass defect

Kenneth S. Krane, Introductory to Nuclear Physics, defines mass defect as Δ=(m(A,Z)-A)$c^2$, where m is the mass of the nucleus with atomic number Z and mass number A and he says that given Δ, we can ...
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Energy released during fission using equation

Im trying to caculate energy released during this equation. LHS: Binding energy of $neutron=939.576$ Mev Binding energy of U$-235=1783.65$ Mev RHS: Binding energy of Tc$-112=936.32$ Mev Binding ...
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What is the relation between the atomic number of material, density and radiation detection for semiconductor radiation detectors?

Lead is considered to be the one of the preferred materials to shield against radiation due to its high atomic number and density. Can the atomic number and density be applied to materials for ...
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Fermi theory of allowed beta decay

In Fermi theory of allowed beta decay, when we consider coulomb correction for the electronic wave functions then the coulomb correction increases the probability of electron emission and decreases ...
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Nuclear rotation wavefunction

I am a bit confused by the quantum numbers used to describe the rotation of a nucleus. In Wong's book these are J, M and K, which represent the rotational quantum number, its projection along the lab ...
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Effective theory for ω → π + γ → 3γ radiative meson decay?

Looking for accounts of omega-mesons decaying, eventually, into three photons, I found (just) the old M. Feldman et. al.: "Neutral Decay of the ω Meson", Phys. Rev. 159, 1219 (1967) (doi:10.1103/...
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Why does the heaviest synthetic element have about the same binding energy per nucleon as an alpha particle? [closed]

I noticed that the heaviest element ever synthesized has only slightly more binding energy per nucleon than an alpha particle. The next element after it would probably have equal or less binding ...
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Deuteron nucleus, what is the wavefunction (including isospin)?

What is the exact form of the wavefunction of the deuteron nucleus. Without electrons. Only neutron and proton combined to a total wavefunction. In the ket-notation I have something like this: $| \...
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2answers
101 views

Where does the electron come from when a free neutron transforms? [duplicate]

I'm reading in Tales of the Quantum (page 68) that "Each neutron is made up of one up quark and two down quarks. In a free neutron one of the down quarks will transform into an up quark, turning the ...
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Static and dynamic excited states

I am reading about excited levels in nuclei (I am mainly following Wong's nuclear physics book) and I am a bit confused about the nature of the excited states. In the one particle picture (mainly ...
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Deutron bound state problem (2 body problem)

In deutron if we calculate the potential depth for just the bound case (that is, taking the binding energy as zero), we get the minimum potential depth $25 \; Mev$. But when we consider binding energy ...
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How can there be nuclear spin-orbit interactions with only neutral and positively charged particles in the nucleus?

At the atomic level, spin-orbit interaction is motivated by the magnetic field experienced by the negatively charged electron orbiting the positively charged nucleus. However, at the nuclear level, ...
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Quadrupole moment

What information does the quadrupole provide? I've seen many definitions on the internet, but I don't understand the relation between them. What is the relation between knowing that the quadrupole ...
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Are specific energy levels the same distance away from the nucleus for all elements?

Atomic radius decreases across a period, but does this mean specific energy levels are different distances away from the nucleus for different elements (eg- the 2nd energy level)?
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Has a 3D chart of nuclides ever been published or proposed $(N, Z, S)$? What information might it show?

Phys.org's 'Strange' glimpse into neutron stars and symmetry violation leads to the new Nature Physics Letter Measurement of the mass difference and the binding energy of the hypertriton and ...
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Need help understanding a radioactive decay question

I have the following question: A stationary nucleus of uranium-$238$ undergoes alpha decay to form thorium-$234.$ The following data are available. Energy released in decay $4.27 MeV$, Binding ...
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When exactly are protons attracted to other protons and neutrons?

When proton and proton neutron and neutron proton and neutron are attracted to each other or repelled from each other in terms of strong interaction (ignoring electromagnetic interaction)? I read ...
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Isotope shift in molecules

Is the isotope shift between 2 (low lying) vibrational levels of the lowest 2 electronic levels (of a diatomic molecule) the same, no matter what the 2 levels are? For example, is the isotope shift ...
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Ionizing materials [closed]

My question is pretty simple: Let's say I have an object composed of tow different substances. Is it possible to only ionize the particles of one of the two materials without also affecting the ...
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enriched fuel in reactors

Why is it not possible to use hot neutrons and enriched fuel in reactors? It works in fast reactors where the enriched fuel is necessary. Fast hot neutrons wouldn't give energy to non-enriched fuel. ...
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Can an isotope also be an ion?

In an element when the number of neutrons differs than that of protons, it is called an isotope. An ion is formed when an atom gains a net charge due to loss or gain of an electron.
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Does the equation $E=mc^2$ hold good for the non-fissionable materials also?

Though we know that the equation $E=mc^2$ holds good for the fissionable materials, I want to know whether this equation holds good for non-fissionable materials also or not? I want to know whether ...
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What is a/the $K^*$ meson, and why is it important?

I know that the standard pseudoscalar $K$ mesons are: $K^+$: valence quark content $u\bar s$; electric charge $+1$; spin $0$; parity $-1$; $K^-$: valence quark content $\bar u s$; electric charge $-1$...
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Is every chemical reaction a nuclear reaction?

This is a PhD-level question that I'm sorry to say is likely to annoy many a high school teacher or university professor trying to get their students to understand the difference between chemical and ...
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Low-lying excited states in nuclei

How are the parity and spin of excited states of nuclei measured experimentally. I imagine that the energy can be easily measured by exciting the nucleus (by colliding it with a nucleon or electron ...
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Nuclear force behavior

I am confused about when the nuclear force is attractive and when not. Based on deuteron (the book I am following is Wong), we see that we can't have bound state with isospin T=1 (otherwise we would ...
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Understanding interaction between two quarks

Two protons and two electrons repel each other as they have same charge. Protons and electrons attract each other since they are oppositely charged. A single proton is made up of two up and one down ...
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How many $pep$-related electron-neutrinos $\nu_e$ does the Sun produce?

In the sun neutrinos can be produced by the rare proton-electron-proton (pep) reaction: $$ {}^1_1 H + e + {}^1_1 H \to {}^2_1 H + \nu_e $$ How many pep-related electron neutrinos does the Sun ...
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Electromagnetic radiation emission

Does Bremsstrahlung radiation produce only a certain type of electromagnetic radiation (for example X-ray) or can it also produce visible light when the trajectory of the incoming electron is not ...
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If nucleons are tied together are their quarks closer with each other than in the single nucleon?

If the volume of the core of an atom is the sum of the volumes of every single nucleon does this mean that quarks of two neighbouring neutrons are much closer than the quarks in each of the two ...
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Physical explanation of spin-orbit interaction in many-electron atoms & nuclei

The electron of a hydrogen atom or any hydrogenic ion sees an internal magnetic field $\vec{B}_{\rm int}$ due to the proton or the nucleus in relative motion w.r.t the electron. The spin magnetic ...
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Why is the $\rm CNO$ cycle is much more efficient than the $p$-$p$ cycle?

Why is the $\rm CNO$ cycle is much more efficient than the $p$-$p$ cycle?
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Pair production limit

We know that a gamma photon with energy that is higher than 1.02 MeV produce electron and positron when its close to the nucleus. So, my question is if the photon has a very high energy, lets say 70 ...
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How to determine the isospin of a pair of nucleons?

While I was reading from the book of Brussaard on shell-model applications in nuclear spectroscopy, he mentioned that isospin of a neutron-neutron pair couple to $T=1$. On the other hand, if it was ...
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Why does the same proportion of a radioactive substance decay per time period? (half life)

Just wondering, if decay is random, why does the activity half every half life, as in, why does it have to reduce by the same proportion in the same time period?
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Small nuclear reactor safety characteristics - meltdown radii

So most nuclear plants are large in scale, producing ~1000 megawatts. I've learned about the rating systems for meltdown management, which involve site radius and wind direction to estimate dust ...
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Why is there a link between binding energy per nucleon and fission energy?

"The reason energy is released in fission is because the daughter nuclei have a greater binding energy per nucleon." I just can't get my head around this for some reason. I am in high school physics. ...

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