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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What physical properties make fusion of iron unlike lighter nuclei in main sequence stars?

I understand that after fusing lighter nuclei, a main sequence star will either stop fusing or the fusion does not release enough energy to continue the sequence. What physical properties make iron ...
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Is neutronium stable at room temperature and pressure?

Is neutronium stable at room temperature and pressure? I understand that it is created under different conditions but are those conditions required to keep it in that state?
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Why will nuclear fusion ever be energy net-positive?

Question from a layman: In nuclear fission, you don't do all the work to split each nuclei every time. You set things up in a clever way so there is a chain reaction. Previously split nuclei cause ...
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Why, in low energy situations like atomic physics, are massive particles found to be in integer number states?

In quantum field theory electrons are conceptualized as quantized excitations of the quantum electron field. Generically the electron field can be in a superposition of number states. This is related ...
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Would superconductors made from heavy radio-isotopes transition at higher temperatures?

I read somewhere that heavier variants of water (using deuterium or hydrogen) melt at higher temperatures compared to normal water. A simple argument for why this is could be the following: heavier ...
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Would superheavy muonic atoms be more stable than light muonic atoms such as muonic helium (hydrogen 4.1)?

Once we start dealing with nuclei the size of gold onwards the inner 1s orbital of an electron approaches relativistic speed. Now it's well known that muonic helium (hydrogen 4.1) has a mean life-time ...
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Difference between BE per nucleon and seperation energy of nucleon

What is the difference between Binding energy per nucleon and seperation energy of nucleon?
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"Lowest yield" atomic weapon possible [closed]

I would ask that folks be tolerant of my ignorance in this field. When discussing tactical and strategic nuclear weapon yield I wonder about what is the lowest possible fission weapon is possible. A &...
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Confusion on states in level scheme in the popular deuteron isospin and spin explanation

I'm having trouble understanding a specific part of the classic deuteron example when introducing Isospin. I have seen this exact example in multiple lectures and textbooks (recently "Nuclear ...
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How to find pulse width and repetition rates of proton beam using TOF?

Having parameter such as flight path, charge(q), mass and energy. How do I find the repetition rates and the pulse width?
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If muons had long enough half lives, could muon-catalyzed p-p fusion be viable?

I was reading about muon-catalyzed fusion and how the "alpha sticking problem" is a major barrier to viability, but when you fuse two protons together you get deuterium instead, which still ...
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A single alpha particle can ionise atoms by ripping off their electrons, though can they only ionise a single atom or a bunch of them?

I was reading through answers on the internet and they basically said that alpha particles rip off two electrons to become a normal Helium atom, my question is can it rip off two SEPARATE electrons ...
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What's the lifespan of Deuterium and Helium-3 in the Sun?

What's the lifespan of Deuterium and Helium-3 in the sun? How long on average, the Deuterium and Helium-3 atoms last in the Sun's core?
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Why does a tritium nucleus have a higher mass than $^3\rm He$?

$^3\rm He$ has a lower (nuclear) mass than tritium which is why the latter decays into the former. This is not explained by the semi-empirical mass formula, which would predict a lower binding energy (...
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How big would a star made of pure deuterium have to be to start fusion?

$D$-$D$ fusion happens much more easily than proton-proton fusion, so I imagine a star made of pure deuterium could be much smaller and still have fusion. Are precise size limits known? How does ...
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Velocity of ions in mass spectrometry

Suppose the gas contains two sorts of atoms (for example two isotopes of one element) with different masses. The electric force between the electrodes of in the gas chamber which accelerates them is 𝑞...
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Electric Quadrupole Moment

Electric quadrupole moment is the measure of the deviation of the shape of the nucleus from spherical symmetry, and for a closed shell(considering the shell model) the Q.M = 0, my question is how ...
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What is the minimum kinetic energy required for an electron to be confined in a nucleus?

I have heard that there was a hypothesis that instead of neutrons inside the nucleus we could have thought about protons + electron pairs equal to the number of neutrons. i.e nucleus consists of 2Z ...
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Does the nuclear reactor remain radioactive after fuel assemble have been removed? [closed]

Uranium pellets are packed as fuel rods, using Zirconium Alloy Cladding. In a steady operational state rector core will be full of radiation. But suppose that all fuel rods are withdrawn will the ...
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How can there be more than one stable isobar for a given atomic mass number?

It can't simply be because the energy gap is less than the mass-energy of an electron. Electrons can participate in decay through electron capture. And there's always one least energetic combination ...
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How to approximate the activity of radioactive product in chain decay?

I am trying to understand how do I get approximation for the activity for a radioactive nuclide that produced during a chain while the activity of the source is given at time $t_0$. For example lets ...
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Is a nuclear detonation wave on a gas giant like Jupiter possible?

I've seen papers doing detailed calculations showing that it's not possible to create a propagating nuclear detonation in Earth's atmosphere or oceans, e.g., this paper. Is it known whether it's ...
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Why can protons and neutrons be close together in a nucleus despite the uncertainty principle?

Vol II, Chapter 1 of the Feynman Lectures explains why negative electrons do not get closer to the positively charged nucleus despite the great attractive force: If we try to confine our electrons in ...
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General Half-life calculation for an abitrary nucleus

I have been getting back into physics and I was wondering whether there was a generalized half-life equation for any given nucleus composition. For instance for gold isotope 210-AU. Is it possible to ...
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How would nuclear fuel enriched with oxygen 18 behave in a reactor?

A lot of nuclear reactors use fuel based on uranium oxides (mostly dioxide). I know that oxygen 18 has a slightly smaller neutron-capture cross section than the other stable isotopes. I wondered ...
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Why are atoms made up of only certain particles (protons, neutrons, electrons)? [closed]

Does it have to do with mass? I know particles like muons have the same charge as an electron, so why can't we have an atom that is made up of protons, neutrons, and muons? Does the particle's mass ...
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What temperature is required to affect stability of the nucleus

According to answers to "What is the temperature of an atomic nucleus?" the temperature inside a nucleus is in the thermal equilibrium with outside environment. So for an outside temperature ...
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What may cause voltage between 2 distant probes of multimeter in apartment room?

In an empty apartment room,my multimeter shows 3.6 mV voltage when I put 2 probes with 2 meters distance. I am curious,what may cause voltage between 2 distant probes of multimeter in apartment room? ...
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Do Neutrons Have a Charge Radius?

The radius of a proton is described as a "charge radius", about 0.84 fm. The neutron is about the same size, 0.8 fm, but has no measureable charge. Is this a contradiction? Are the two ...
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How long before the Sun has given off enough energy=mass for a one meter thick Dyson Sphere at earths orbit?

Just for fun: As energy can be converted into mass - what if we had some kind of magic technology which can convert photons into carbon atoms with 100% efficiency. I realize its not as easy as just ...
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Does water undergo thermolysis if a nuclear device detonates within it?

I caught a glimpse of the Wahoo nuclear test, an underwater test as part of Operation Hardtack I, and I wondered; that's a LOT of thermal energy going directly into the surrounding water, with this ...
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Is it possible for there to exist metastable exotic atoms?

I've been quite fascinated with the invention and discovery of exotic atoms such as: positronium, and muonic hydrogen etc... Now I know positronium has a longer than usual lifetime because it is in a ...
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What are phenomenological models and ab-initio models in terms of dense matter?

I've tried to grasp the concept of phenomenological and microscopical ab-initio models when it comes to EOS of neutron star matter . I can understand the meaning of them in general, but I find it ...
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Non-relativistic nuclear charge-current commutation relation

On the second page of the paper [1], the following commutator is given for the non-relativistic nuclear charge-current operators: $$ \left[ J^{0}(\boldsymbol{x}), \boldsymbol{J}(\boldsymbol{y}) \right]...
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How much energy from neutrinos does a Helium flash create?

How much energy from neutrinos is given of by a solar mass star when it undergoes a Helium flash?
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Can fusional nuclear compression theoretically be achieved with a unidirectional compressive force?

In other words, is it theoretically possible to get an energy-profittable nuclear fusion reaction by simply slamming compressive force into some nuclei from a single laser compressing from one ...
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Why don't deuterons produce a helium-4 nucleus when they fuse?

I would expect two deuterium nuclei to fuse straight into a single helium-4 nucleus, because that's by far the most stable way to arrange 2 protons and 2 neutrons. But instead, any two fusing ...
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How do mesons explain nuclear stability?

I understand that nuclear stability is explained by the presence of the residual nuclear force, which in turn is a result of the strong nuclear force, which I believe, is mediated between quarks via ...
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Research Areas which combine Computer Science with Physics? [closed]

Throughout my high school i loved physics very very much. I always wanted to a PhD in physics. Along with i thought of pursuing space science. But due certain reasons i ended up in Computer Science. I ...
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Would it be possible to make a Gun type nuclear bomb using Isotopically pure Plutonium-239 [closed]

I know that it's normally not possible to make a gun type nucelar bomb using plutonium due to high rates of spontaneous fission. But that's primarily due to the plutonium 240. If you instead used ONLY ...
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About binding energy, mass defect and enegy released in a nuclear fusion

I know this question looks very similar to many others but I actually think it is not the same, because I was looking for a possible answer for hours. The question is about the first step in the pp ...
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Why we have not observed one proton and one neutron nuclear decay? [duplicate]

I'm learning about nuclear decays: Alpha (helium nucleus, +2) Beta (electron) Gamma (photon) Neutron But why helium nucleus? Why not hydrogen nucleus (deuterium)? I mean why two protons and two ...
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Nuclear resonance spectroscopy: why not use Co-57 radioactive source instead of synchrotron?

In nuclear resonant spectroscopy experiments, typically a sample containing Fe-57 nuclei is used. These nuclei are then excited via a synchrotron-based X-ray source. Why is it not common to simply use ...
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Calculate total number of fluence on a moving detector

We have a radiation zone emanating from a source located at $(x_0, y_0, z_0)$. We also happen to have the flux due to this source measured in a 3d cylindrical grid surrounding the source with a flux, $...
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Why aren't fusion reactors using centrifuges?

If fusing of nuclei in stars requires pressure, heat, and gravity, why not use a centrifuge to increase the gravity? We currently have the technology to make diamonds, and generate immense ...
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What is the dependence of fusion power of the particle energy at fixed pressure?

The fusion reaction power depends on the reaction rate. The reaction rate depends on the concentration and the cross section.The cross section depends on the energy of the particles or temperature. ...
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Minimal condition(s) for the emission of a photon to occur

I was working out a practice problem where you needed to give all the possible states (where the emission of a photon occurs) of a H-atom at excited 5d state. So I started by whriting down all the ...
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Are electric force and strong force equal in magnitude?

Should the electric force and the strong force be equal for a nuclei to be stable? Because if perhaps, the strong force is now more than that of the electric force, then shouldn't the nucleus collapse ...
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Can nuclear spallation be viewed as a form of fission?

I sometimes find it helpful to reduce specialized terms to their simpler roots. For instance, alpha emission is really a form of asymmetric fission. And so is neutron emission. The outcome of a ...
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A nuclear fusion generating cart

In an unrealistic thought experiment, suppose I had a $100$ meter track with a cart ontop that had a "pocket" on the front of the cart. Suppose further that this track and cart were in a ...

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