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0answers
24 views

Can the half-life of a free neutron be calculated or is it just empirical? [duplicate]

Everyone keeps telling me its just 10.3 minutes and no one knows how to get that number form theory. Any idea?
2
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2answers
157 views

Why are neutrons present in an atom? [duplicate]

I have a very stupid question perhaps, but please answer me. An atom consists of electrons, protons, neutrons. protons are positively charged and electrons are equally negatively charged. The charge ...
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1answer
73 views

Neutrino-Neutron Interaction Feynman Diagram (W Boson Direction)

I am currently studying differential cross sections for my Nuclear Physics module. I'm looking an experiment where muon-neutrinos are interacting with nucleons in a scintillator producing muons (which ...
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3answers
76 views

The role of W bosons in the weak nuclear force and beta decay

I am a beginner Physics student and I am studying the weak nuclear force and how particle interactions work. Now, from my book and the Feynman diagram, I learned that a neutron can change into a ...
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1answer
48 views

How to calculate scalar neutron flux

I am really confused about the difference between flux and scalar flux. I have a specific question: If we have a parallel neutron beam of strength $\phi_0$ given in neutrons/cm$^2$s, incident on a ...
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4answers
93 views

Can neutrons be synthesized purely from protons and electrons?

Can neutrons be synthesized purely from protons and electrons? Note: I'm looking for reactions that do not require neutrinos or any particles besides just protons and/or electrons as reactants.
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1answer
70 views

How the neutron magnetic moment was measured?

How was the neutron magnetic moment measured? Was the antineutron magnetic moment measured too?
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2answers
290 views

How detectors in particle colliders can differentiate neutrons from antineutrons?

Their mass is the same. None of them interacts with EM fields. And their decay (around 1000s) is far too slow to see their decay products yet in the detector. How is it then possible to differentiate ...
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1answer
56 views

What is a Hulten potential?

What is the Hulten potential? When is it used? How is it derived? I vaguely heard about in the context of neutron synthesis / quantum mechanics. thanks
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3answers
448 views

Anti-neutrons, anti-quarks, isospin: What is observed and what is derived?

I would be a little more restrained with the existence of antineutrons. First at all - if I understood right - the existence of antiquarks is hypothetical. If one not agree with this please refer to ...
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5answers
3k views

How is it possible to accelerate a neutron?

It is possible to accelerate a charged particle in an electric field, how is it possible to accelerate a neutron? How can we control its velocity?
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1answer
55 views

If one is talking about antineutron production, what is the charge exchange?

In this question was given the antineutron production in the way $$ p + \bar{p} \rightarrow n + \bar{n}. $$ Internet search gives one source only where the charge exchange is mentioned. They talk ...
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1answer
66 views

How to create antineutrons?

Creating a beam of antiprotons allows to create antineutrons by charge exchange. How does this exchange work? The question pops up after the question "Is there a strong evidence of antineutron ...
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2answers
110 views

Is there a strong evidence of antineutron existance?

Wikipedia explains: The antineutron was discovered in proton–proton collisions at the Bevatron (Lawrence Berkeley National Laboratory) by Bruce Cork in 1956, one year after the antiproton was ...
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2answers
98 views

Is neutron decay a purely electromagnetic phenomena?

Until reading the Phys.SE post here about the neutron decay I never feel strange the fact about the antisymmetricity of this decay. But indeed why this decay is antisymmetric. The neutron is his own ...
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3answers
104 views

Experiment demonstrating interference patterns of neutrons

The question is about experiments (and references) that demonstrate interference patterns of neutral (chargless) particles (fermions), especially neutrons. Like double-slit experiments for neutrons ...
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1answer
56 views

What happens to Cosmic Ray Neutrons at the Earth?

When Cosmic Rays fall down from the sky, they produce lots of neutrons. They are "added" to the Earth system, so what is happening to them? Do they decay to protons? It would follow that they then ...
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1answer
157 views

What is the dominant interaction between two neighboring neutrons?

Suppose they are held 10 nm apart. What is the dominant interaction between them? The magnetic dipole interaction or something else?
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0answers
100 views

Why is free neutron unstable but free proton is stable?

Aren't they basically made up of the same stuffs (quarks) in almost the same configuration?
1
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1answer
55 views

Will an anti-neutron annihilate a regular neutron even though they have no charge

Since neutrons have no electric charge will an anti-neutron annihilate when it comes into contact with a regular neutron as protons and anti-protons do? if so what causes it to annihilate?
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1answer
61 views

Energy dependent cross sections for neutrons

Do you know where I can find a table with energy dependent cross sections for neutrons? Thanks!
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1answer
21 views

Can an inhomogeneous magnetic field be built to slow down and catch a neutron?

Neutrons have a measureable magnetic dipole momentum from their intrinsic spin. Is it possible to slow down and catch the neutron by imposing a force by an inhomogeneous magnetic field. I think the ...
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0answers
24 views

How does beta+ decay actually occur? [duplicate]

I'm having difficulty in understanding beta plus decay. How can a proton which has slightly less mass than neutron transform into a neutron, positron and neutrino? Form where does the extra mass for ...
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0answers
80 views

Calculating the Neutron Stopping Power of complex materials

Is there a fast and convenient way of calculating the neutron stopping power of materials, consisting of multiple elements (e.g. doped crystals) without the need for Monte Carlo Simulation, that is ...
2
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2answers
47 views

Do molecular bounded systems shield or reduce neutron cross-sections?

When talking about neutron cross-sections, literature is usually investigating isolated cases of Neutron + Atom. Here, the abundance of hydrogen is dominating neutron fluxes through material. I ...
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0answers
56 views

Compare Dynamics of Cosmic Ray Neutron Radiation

Examining cosmic ray neutron radiation near ground by neutron monitors for example (http://www.nmdb.eu), different stations show similar dynamics in the signal. At one station, I like to "substract" ...
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0answers
51 views

Beta-decay of the neutron

Could you please tell me, where can I find a straightforward calculation with all details of beta-decay of neutron? To find the amplitude and to square it is difficult, but possible. The main problem ...
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2answers
156 views

Catching/harvesting neutrons

This question has several parts. How does modern science catch free neutrons that are just floating around? Is there anyway to "pull" a neutron off any atom that does not involve our current ...
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0answers
84 views

Is that true that neutron activity on Earth in 2013 is unusual?

I have just read curious statement on this website: http://www.trinitas.ru/rus/doc/0016/001d/00162241.htm (unfortunately this is in Russian, but I will try to translate) "В заключение можно отметить, ...
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1answer
340 views

How would neutron matter appear to the naked eye?

Neutron matter is matter comprised entirely of neutrons, as it exists in neutron stars. Most optical phenomena encountered in everyday life, such as light reflection and spectral absorption (i.e. ...
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1answer
211 views

Will a moving neutron produce a magnetic field around it?

Will a moving neutron produce a magnetic field around it? I know that neutrons have no charge, so magnetic field should not be produced along it...but neutrons have a magnetic moment. So why can't ...
5
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1answer
185 views

What are the strongest sources of collimated neutrons and protons?

I am imagining an unusual experiment which will require intense beams of either protons or neutrons. The experiment would work better with neutrons, but neutron sources are much weaker messier so I ...
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3answers
241 views

Free neutrons pass through most materials but how do they damage materials?

Neutrons has no charge so they are hard to interact with materials. That's what I'm thinking. But they collide with atoms and it causes nuclear fission. And they can also be a dangerous radioactive ...
1
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1answer
138 views

How to solve the Fukushima incident?

I am trying to find out if it is somehow possible to take all this nuclear material, put it in some type of gamma chamber or blast it with neutrons to change the uranium isotopes into something ...
3
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2answers
1k views

What is the shielding in nuclear reactors mainly against?

I have a little knowledge about ionizing radiation and I have been confused over why nuclear reactors need these massive shields. So, if I am not mistaken, Alpha and Beta radiation are not that ...
3
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2answers
514 views

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
1k 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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3answers
1k views

What stabilizes neutrons 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
56 views

Must neutron speed and diffusion speed be comparable for neutron scattering experiments to be probe atomic diffusion?

Neutron scattering experiments are sometimes used to study atomic diffusion in solid materials. My intuition is that the typical speeds of the atoms diffusing in the material--say, the diffusion ...
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1answer
145 views

Neutron conversion to energy? [closed]

Numerical: If a neutron be entirely converted into energy how much energy would be produced. ($M_n = 1.6743\times 10^{-27}$kg.) Explain
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1answer
168 views

Do small-angle coherent scattering experiments really see coherent effects over arbitrarily large distances?

Short version After integrating over all possible outgoing angles, the total cross-section of coherent elastic scattering from a fixed target of characteristic length $L$ scales like $L^4$. Does ...
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1answer
130 views

Neutron scattering for a critical magnetic-ordering system : what about critical opalescence?

Liquid-gas transition critical point is believed to share the same universality class as the 3D Ising model. We know that the liquid-gas transition is characterized by a phenomenon called critical ...
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0answers
33 views

Is there anything to prevent paired-up neutrons from a complete overlap

The reason "neutrons don't overlap", as DarenW explained it, has to do with intricate forces at play that take into account the spins, iso-spins and symmetry of the wavefunctions. However, assume I ...
2
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1answer
290 views

Spin and Parity of $^{17}_8 O$ excited states

$^{17}_8 O$ quoted here has a spin of 5/2 and parity of +1 for the ground state, I agree with this, the unpaired neutron is in the $1d_{1/2}$ state so l = 2, spin = 5/2. Now I want to figure out the ...
3
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2answers
221 views

Neutron generators as Fusion reactor

One way of generating neutrons is by fusing D-D or D with T. In neutron generators that work by acceleration D-ions into a solid matrix of e.g. metal and T or D (metal hydrides). Such generators can ...
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0answers
30 views

Nuclear structure [duplicate]

Possible Duplicate: Are the protons and neutrons in the nucleus arranged in any particular way? Isotopes have different numbers of neutrons. Essentially my question is: how does the ...
0
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1answer
255 views

Explosion of a Neutron Bomb

Watching "The Dark Knight Rises", Bane announces halfway into the movie at the stadium that what they have is a neutron bomb. But then at the end of the movie there is an actual nuclear explosion ...
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1answer
41 views

What is pulsed neutron diffraction?

I have tried a google search and checked my condensed matter books but I can't find out what pulsed neutron diffraction is and how it differs from inelastic neutron scattering.
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1answer
71 views

Could much of the “missing” antimatter make up neutrons?

A neutron can decay into a proton, an electron, and neutrino. Could an antiproton, a positron, and a neutrino combine into a neutron? Could this be where much of the "missing" antimatter is?
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3answers
2k views

What does a subatomic charge actually mean?

I was recently reading a popular science book called The Canon - The Beautiful Basics of Science by Natalie Angier, and it talks about subatomic particles like protons, neutrons and electrons in ...