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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Measuring neutron separation energy

In Introductory Nuclear Physics, Kenneth S. Krane describes neutron separation energy (page 65), and shows a list of measured values (Figure 5.2). What experimental setup is used to measure these on ...
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Energy of the nucleon bag (MIT bag model)

I am studying MIT bag model. The Lagrangian density for this model is $$ \mathcal{L} = (i\bar{\psi}\gamma^\mu\partial_\mu\psi - B)\theta_V - \frac{1}{2}\bar{\psi}\psi\delta_S .$$ The nonlinear ...
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Do air-crafts fall when exposed to nuclear radiation? [on hold]

I don't have a background in physics. However I wanted to ask a question relevant to the Chernobyl disaster. From what I found online the helicopter that tried to release sand to shut down the fire ...
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What if nuclear chain reactions were not possible

Nuclear fission chain reactions occur when a nucleus breaks apart, producing at least one neutron, which then causes nearby nuclei to fission, a multiplying process when the average number of produced ...
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What is the minimum safe distance from a neutron source through the atmosphere?

Imagine there is a source of neutrons emanating from a point in space. Maintaining line of sight, how far away from the neutron source must you be to preclude neutron poisoning if the neutrons only ...
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Does fusion only occur with ions?

In nuclear fusion, the particles require enough energy to overcome the Coulomb barrier. The Coulomb barrier is caused by the Coulomb force, which is created by the protons repelling each other because ...
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Why doesn't the nucleus have “nucleus-probability cloud”?

While deriving the wave function why don't we take into the account of the probability density of the nucleus? My intuition says that the nucleus is also composed of subatomic particles so it will ...
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How can neutron be converted to proton and electron?

Since a neutron and a proton are made up of quarks and an electron is a lepton, how can a neutron yield an electron?
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Relation among the dead time, recovery time and resolving time of a GM counter

I have been researching a lot for my assignment about the relation among the dead time, recovery time and resolving time of a GM counter. Most of the articles I came across have varying definitions on ...
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Proton to Neutron conversion

Is there a way to convert a proton in a nucleus to a neutron? Hyperphysics writes that if a proton was supplied with 1.29 MeV of energy, there would be enough energy to make that conversion. Has ...
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How is this dose rate equation derived?

I've been trying to determine how the following equation for dose rate from a gamma point source has been derived, I've seen it in numerous books with no clear explanation for its derivation, ...
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37 views

When do we call a composite particle system bound?

I know that to see if a system (for example, a nucleus) is a boson, we see the total spin on it. For example, an even number of protons and neutrons would make the system a composite boson. The same ...
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Calculation of number of nuclear fusion reaction per cubic meter or kilo

In wikipedia article about Nuclear fusion there is a list of nuclear fusion reaction here. Is there a equation how to calculate number of nuclear fusion reaction per second per cubic meter or per kg ...
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Modern physics dealing with atoms and nuclei [closed]

Can any one explain what happen after bohr's model of atom?
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Can one show that hypernuclei are always unstable?

Normal atomic nuclei are composed of protons and neutrons, where the local interactions stabilize the neutrons that are unstable in isolation. Hypernuclei have one or more strange hadrons beside the ...
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What is the reason that conservation of momentum is conserved in nuclear reactions?

I understand that in nuclear reactions such as fusion or fission, it is known that energy released due to the mass defect to obey the conservation of energy. However, researching online; I fount ...
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101 views

Why $1 \ \mathrm{fm}$ is often used in modern physics?

In the International System, we all know that a one femto (or one Fermi) is equal to $$1 \ \mathrm{fm}=10^{-15} \ \mathrm{m}$$ What is the historical reason why this unit of measure was adopted as ...
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Can there be an atomic nucleus where there are more protons than neutrons?

As far as I know, number of protons is less that or equal to the number of neutrons in any atomic nucleus. But is there any possibility that there exists a nucleus where the number of protons exceeds ...
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Is the mean life being 1/$\lambda$ a coincidence or a definition?

We were studying radioactivity and after we worked out the half life to be $ln2/\lambda$ the professor then said, this is the average time it takes for half the nuclei to decay to find the average ...
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Proton and Antiproton decaying into positive and negative pions [duplicate]

A proton and an antiproton annihilate at rest (or in a $p\bar{p}$ atom in an S state) into pions. Show that the decay into a $\pi^+\pi^-$ final state is possible from a $^3S_1$ state, but not from a $...
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Can Hartree-Fock-Bogoliubov be used for dynamics?

I am aware of Hartree-Fock as both a tool to find interacting ground states for fermionic systems (eg the Roothan self-consistent field procedure). One way of deriving the ground state method is to ...
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A proton and antiproton annihilate at rest into pions

I'm having a difficult time with this particular problem. I'm really hoping for some guidance. A proton and an antiproton annihilate at rest (or in a $p\bar{p}$ atom in an $S$ state) into pions. (a) ...
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How would I go about calculating the energy input needed for a cyclotron reactor?

I'm trying to do some math regarding cyclotron reactors. I've figured out how to calculate the radius of a particle's motion in the cyclotron, a rough way to calculate energy output, but I have looked ...
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How does the strong force work in plasma?

For a very long time I have thought of inter-elemental conversion, like lead to gold, or just separating the components of one element to create another. From my understanding, you could overpower the ...
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Can a nuclear weapon destroy another nuclear weapon in flight? [closed]

I was thinking the other day, we have quite a few nuclear weapons in our arsenal. Say a country uses ballistic or cruise missiles on us. Can't you send up another nuclear weapon and detonate it within ...
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Is a chain fusion reaction of deuterium oxide (heavy water).possible?

I think it is the case that at very high temperatures that two deuterium atoms can be made to fuse to produce helium and a release of energy. I think under appropriate physical conditions this can ...
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How is the speed of nucleons in the nucleus measured?

This article claims that "nucleons in a dense nucleus exceed 25 percent of the speed of light". How do you measure or infer the speed of nucleons in the nucleus? Note added later: I'm looking here ...
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How are thermonuclear weapons possible?

Given the fact that thermonuclear devices are a mix of fission through enriched uranium whose energy initiates the fusion in surrounding deuterium. Question is (how come) fission raises temperature so ...
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Superman threw a net with a lot of nukes into the Sun. What happens now? [on hold]

The iconic scene in "Superman IV: The quest for peace" shows the eponymous character throwing a net filled with nuclear missles into the Sun. If that were to happen in real life, what would happen as ...
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Step-like contribution to background $\gamma$ ray peaks

I'm reading the paper "Analytical functions for fitting peaks from Ge semiconductor detectors" by R.G. Helmer and M.A. Lee. For $\gamma$ ray peaks the spectral "background" in the region of a peak: ...
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Calculation with gamma constant to find dosis in sievert/hour

This is a serious question as it's related to my work and actual handling of flour-18. (Always behind plenty of shielding). But i'm very curios of the danger without any protection. I'm trying to ...
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140 views

Radioactive Decay ($dN/dt = - \lambda N$)

The formula for radioactive decay, $$N = N_0 \ e^{- \lambda t}$$ is derived from the following assumption: $$\frac{dN}{dt} = - \lambda N.$$ I understand an assumption has been made that no external ...
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Why does rhenium get a pass on being radioactive? [closed]

Thorium is thought of as radioactive and "dangerous" because its half life is 10 billion years. However, most rhenium is radioactive with a half life of 40 billion years even though rhenium does have ...
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Are neutron star cores thought to be stiffer than photon gases?

The weak energy condition and with the dominant energy condition allow anything from w=-1 to 1 (meaning that the magnitude of the pressure can be at most equal to the total mass-energy density). ...
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How does meson exchange work within large nuclei?

I read the Wikipedia page on Mesons and it mentioned that there both charged and uncharged Mesons that decay into neutrino/electrons and photons, respectively. Unfortunately it didn't elaborate on ...
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Why is the spin-orbit interaction for a nucleus so much more important than the spin-orbit interaction in atomic physics?

In atomic physics, the spin-orbit is a small correction between 1/1000 and 10ppm, so fairly small. In contrast, in nuclear physics the inclusion of the spin-orbit interaction is necessary to reproduce ...
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How much does the distance between electron orbits shrink as proton number increases?

I was watching a YouTube video that briefly mentioned the electromagnetic attraction between the nucleus and it's electrons increases as the proton count of an atom increases. I'd never considered ...
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Assessing the Viability of Nuclear Initiator Device for Energy [closed]

Disclaimer: This question is purely theoretical and is merely intended to serve as a means of creating a model for a nuclear detonator-based power source. No association to weapons is implied. ...
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Is it a coincidence that the maximum number of protons in a stable nucleus is on the order of $\alpha_s / \alpha_{EM}$?

The equivalent to the fine-structure constant for the strong interaction is about $\alpha_s \approx 0.5$ at the proton rest mass energy (and it runs pretty slowly with energy, so it's on this order ...
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Which operations of a nuclear reactor are controlled by humans? [closed]

I understand in a general term how a reactor works, but I was wondering whether they are highly automated or not. Such as do humans control thing such as fuel and coolant flow rates?
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Was Chernobyl Explosion a Small Nuclear Detonation?

The Chernobyl reactor was designed to produce a maximum of 3.2 megawatts of power. It is now estimated to have produced 3.2 gigawatts of power in the final second of its life. The original ...
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What really causes radioactivity?

We know that a nucleus can transform itself by many ways such as fission, alpha decay, beta decay, etc. But what is it that propels this to happen? Is it just the instability of the nucleus in general?...
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Inexpensive nuclear reaction simulation tools

I am interested in seeing if there are any simulation software programs for less than $50 that may be used to simulate how neutrons (energies between thermal and 15 MeV) interact with certain nuclei ...
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why are there no atoms with a few protons but many more neutrons? [duplicate]

I saw a graph in a geology class that showed stability fields of elements. something similar to the one below. I noticed there were no elements that had a few protons but tons of neutrons. I was ...
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How do you correctly identify beta emission reactions given a description like $^{126}_{50}\text{Sn}\rightarrow^{126}_{51}\text{Sb}$?

Ex. “This is an example of what type of nuclear reaction: 126/50 Sn -> 126/51 Sb” I thought it was fusion since the atomic number increased, but it was actually beta- emission with a neutron turning ...
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Can a magnet rip protons from a nucleus?

Pretty self explanatory. I’m wondering if the strong nuclear force could be overcome by a strong enough magnet?
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Can rocks be used to propel rockets? [closed]

Can rocks and soil, or simply any other common form of matter with a mass, be vaporized in a nuclear thermal rocket at high temperatures to provide thrust for the rocket? Wouldn't that be convenient ...
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Q Value for 64-Zn(n,2n)63-Zn [closed]

I've been looking for the Q-value for this reaction for quite sometime now but haven't had any luck with it. What is the Q-value for the equation and how much energy would each of the neutrons ...
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Significance of “MT=” in nuclear science cross sections

I recently came across a measurement on jaea.go.jp/ (a site that publishes nuclear cross section tables). The cross section table had a unit known as "MT" for boron and other elements. I was curious ...
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Any way to definitively determine the products of deuterium-deuterium fusion?

I was doing some reading and came across these two reactions: $D + D \rightarrow \:^3He + n + 3.27 MeV$ and: $D + D \rightarrow \:^3H + H + 4.03 MeV$ (from here: http://hyperphysics.phy-astr.gsu....