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3
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2answers
73 views

Why does a “typical” hydrogen atom have no neutron?

There are quite a few sources (mostly high-school physics textbooks) that I've read which don't give the disclaimer that the hydrogen atom they are using in a diagram is an isotope (as in having ...
1
vote
1answer
25 views

Why don't degenerate gases expand from heat?

Degenerate gases are excellent conductors of heat. However, the fermions that compose the gas will not expand outwards due to heat, except in incredibly high temperatures. Why is this? Does it have ...
0
votes
1answer
34 views

What are the experimental results of neutron -neutron scattering?

I'm curious about does a neutron - neutron scattering (if such an experiment was carried out) is an in elastic process or is it accompanied by energy losses. Additional question: What is the energy ...
-4
votes
2answers
45 views

How many neutrons would it take to boil a gallon of water? [closed]

How many neutrons would it take to boil a gallon of water?
1
vote
2answers
51 views

Arrangement of Nucleons due to Strong Force

I was reading up on the fundamental forces of nature and I was wondering about the arrangements of nucleons due to the strong force. Considering electromagnetic repulsion, having 2 protons "bonding" ...
1
vote
0answers
28 views

Can there be a two-neutron bound state? [duplicate]

Is is possible for two neutrons to be in a bound state, assuming that they only interact gravitationally?
0
votes
1answer
8 views

which unit cell to use for dynamic structure factor in neutron scattering?

I'm trying to calculate the dynamic structure factor for inelastic neutron scattering, but I get a function which doesn't obey certain symmetries of the crystal lattice and which changes depending on ...
0
votes
1answer
59 views

Collision with a stationary Hydrogen atom [closed]

Can some explain me what happens when an electron or neutron collides with stationary Hydrogen atom? What are conditions for elastic and inelastic condition? For example, how to tackle following ...
1
vote
1answer
45 views

Why positron emission is unlikely to occur for nuclei with an excess of neutrons?

Is it because a neutron decays into a proton and electron rather than a positron. Which type of nucleus emits positron and which emits electrons . Is it something to do with beta plus and beta minus ...
0
votes
1answer
46 views

How are neutrons made?

How are neutrons made? Perhaps no-one really knows, but I'll ask anyway. Are they still being made? or were they all made at some early instant of the universe?
1
vote
1answer
39 views

Atomic radii for elements as hard spheres

In neutron scattering, the atoms in a system are considered as hard spheres. Where could I find the appropriate (reliable) values of the atomic radii consistent with this physical picture? Thank you ...
1
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0answers
21 views

Why isn't every magnetic neutron scattering peak a nuclear scattering peak as well?

Neutron diffraction is a well-established technique for determining the magnetic unit cell of magnetic materials. The idea is that nuclear scattering gives you peaks that correspond to the crystal ...
8
votes
2answers
434 views

How does zinc affect fast neutrons?

How does metallic zinc interact with nuclear fission? Is it transparent for fast neutrons, or does it interact as a reflector (tamper), absorber, or moderator, or some other way yet? I'm asking it ...
2
votes
1answer
63 views

Which properties control the strength of strong interactions?

Does the strong nuclear force depend on mass, charge or spin? Accordingly, can we order neutron-neutron, proton-proton and neutron-proton pairs by the strength of the strong force between them?
1
vote
1answer
53 views

Neutron population growth in a reactor

In nuclear reactors physics, the effective constant $k_{eff}$ is defined as $$k_\text{eff} \equiv {\text{number of neutrons in one generation}\over \text{number of neutrons in the preceding ...
1
vote
2answers
139 views

Why don't neutrons cluster on their own?

"The answer lies in their one part in a thousand extra mass. Adding neutrons costs a little in mass, and in Einstein $E=mc^2$ implies that mass equates to energy. So it costs energy to add ...
2
votes
1answer
60 views

Is it possible to tidally lock a neutron star?

As I know, neutron stars are almost perfect sphere and no net moments, does it mean it is not possible to tidally lock it?
1
vote
1answer
30 views

What is the physical interpretation of imaginary terms in the neutron optical potential model?

I'm doing a computational project on neutron scattering and I've found that if you simulate (n,n) collisions on Uranium 238, the program predicts resonances not found in experimental data. The ...
1
vote
2answers
99 views

How is an electron “recycled” in a neutron?

A proton is made up, they say, by 2 up and 1 down quark, drowned in a sea of virual paricles: when an electron is captured this process thereby changes a nuclear proton to a neutron and ...
0
votes
1answer
32 views

Neutron scattering off molecules

From neutron scattering off molecules it is possible to get information about molecules' geometry. Given the size of a particular molecule, what are the criteria for choosing the wavelengh of the ...
3
votes
0answers
12 views

Why is this result wrong for finding speed of a neutron in relation to deBroglie wavelength [duplicate]

So given a deBroglie wavelength 1.8nm and the equations E=hf and E=1/2mv^2 you can get v = 2h/m*(1.8*10^-9) but this is 2 times the expected value. Wherever I look online people use the momentum p ...
6
votes
0answers
164 views

Intensity of inelastic neutron scattering: analitycal expressions

I am currently working with experimental results of magnon spectrum (in antiferromagnet with many atoms per unit cell), which was obtained by inelastic neutron scattering method, but some spectral ...
2
votes
2answers
58 views

Why did James Chadwick use berryllium to discover neutrons?

In Rutherford's alpha particle scattering experiment he used gold foil because it's malleable and can be drawn into very thin sheet. Why did James Chadwick use Berryllium while discovering neutrons ...
0
votes
2answers
121 views

A Neutron Star and an Atom are Similar [closed]

In an earlier question I asked if photons could exist without atoms. Is a neutron star's residual light released similar to an exited atom the difference is gravity hold in the electrons in the star ...
3
votes
1answer
41 views

Neutron activation time for Boron, Silver, and possibly other materials

How do i justify/explain that the time needed to activate Boron is 2 hours and the time needed to activate Silver in water is 45 minutes? Response to comment: In a neutron cross section experiment, ...
4
votes
3answers
115 views

Would a bag of neutrons have temperature?

Neutrons interact with each other only via exchange interaction, while "every-day particles" and their temperatures are governed by electrostatic forces. What are the implications of this difference ...
0
votes
0answers
33 views

Does an atom become positively charged as a result of Beta decay? [duplicate]

Since a neutron breaks down into an electron and a proton, and the electron is emitted as beta particles, the atom has an extra proton (protons>electrons). So, the atom becomes positively charged. But ...
2
votes
1answer
86 views

Is Neutronium possible?

Now I am not talking about neutron stars here. I am talking about a supposed substance with only neutrons in the nucleus. All atoms of this category would have a negative charge and negative charge ...
2
votes
1answer
73 views

Is neutron-neutron fusion viable?

Do I get unusual baryon maybe like pentaquark or just a pair of conjoined twin that is very unstable?
2
votes
3answers
95 views

Head-on collision between two neutrons

If two neutrons were set to collide head-on, being electrically neutral: Will they feel each other's presence due to electrostatic interaction between quarks of approaching neutrons? When they ...
1
vote
1answer
48 views

How are neutron refractive indices calculated?

I have been informed of the fact that neutrons refract similarly to light in accordance to Snell's Law. How would one calculate the refraction index for a neutron?
1
vote
3answers
93 views

Can a neutron decay to the gravitons?

Is it possible that a bunch of neutrons totally decay to the graviton? In other words, does the baryon number conserve in the quantum gravity interactions?
4
votes
1answer
151 views

Why do neutron stars have solid crusts?

A long time ago I read that neutron stars have a solid crusts that are several orders of magnitude harder/stronger than alloys here on the Earth. So how is this possible ? A neutron star has a ...
0
votes
2answers
54 views

Can both types of W boson be responsible for a neutron-neutrino interaction?

My textbooks lists the exchange particle for a neutron-neutrino interaction as being the W- boson. Is this the only option, or can it also be a W+ boson? Nothing jumps out at me that would suggest it ...
1
vote
0answers
37 views

Question on decay constant

I have a model of the radioactivity of a target which is undergoing Neutron Spallation. The Protons are incident upon the target for approximately 200 hours. Within the model, over the course of ...
0
votes
2answers
34 views

Can multiple adjacent reactors use neutron reflector walls in common to save mass?

Reactor designs like fission-fragment and some others use large masses of neutron reflectors to attain criticality. (For that matter, the very first pile did too, and in a staggered form rather ...
0
votes
4answers
78 views

Change in the half-life of a neutron

What would happen if the half-life of a neutron was much more less than it is now? How could this affect the nuclei?
1
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2answers
34 views

Nuclear transmutation of radioactive waste using high-energy neutrons

How likely does this work: Accelerate neutrons to as high energy as possible (particle accelerators/ cosmic rays ...) and hit (small samples of) our radioactive waste with it such that it is converted ...
4
votes
0answers
52 views

Which is the mechanism through which dying stars shed their outer atmosphere and leave behind their core? [closed]

I was looking into neutron star creation and I read that when a star dies, it expells its outer atmosphere and leaves behind a really small really dense nucleus (a white dwarf if the first star was a ...
1
vote
2answers
40 views

Can we create sheet of neutron

I want to know are there any theory or technology to create a neutron matter like neutron star on earth. Even a tiny thin sheet like graphene And how heavy it is if we create 1x1 sqmm of neutron ...
1
vote
1answer
175 views

What happens to mass during beta decay?

Sorry for being ignorant, but I'm in high school and our chemistry teacher barely went over beta decay. I decided to do some research and learned that in β+ decay, positrons are emitted from protons ...
3
votes
2answers
1k views

How does a neutron have more mass than a hydrogen atom's isotope (Specifically deuterium)? [closed]

A hydrogen atom weighs 1.00794 u ± 0.00001 u. The mass of a neutron is slightly above it, at 1.00866491600(43) u‎. I'm wondering, how does a neutron weigh more than itself plus 2 extra particles, as ...
21
votes
2answers
2k views

Why is boron so good at neutron absorption?

Why is boron so good at absorbing neutrons? Why does it have such a large target area compared to the size of its nucleus?
3
votes
1answer
105 views

How does neutron reflection work?

What I mean here isn't what is it used for, but what's actually going on with the reflector. There are a lot of sub questions to this. how much energy is lost in the act of reflection. not ...
2
votes
1answer
64 views

Evidence for standard model description of neutrons

as I don't know too much about experiments I have the following question concerning the evidence about the quark constituents in neutrons. After a quick google investigation I found some sentences ...
12
votes
2answers
1k views

Is a neutron star basically an isotope?

Since a neutron star is basically just a vast amount of densely packed neutrons, I was wondering whether those neutrons form a single "atom" (of atomic number zero) or whether they are further apart ...
2
votes
1answer
490 views

Gamma spectroscopy - Table of radioactive isotopes with gamma energy search

For anyone doing gamma spectroscopy by hand, the task is considerably eased by tables like this: http://nucleardata.nuclear.lu.se/toi/ Where not only can you search for particular nuclides, but you ...
0
votes
1answer
31 views

Gamma spectroscopy - neutron activation of a stable isotope

Question about gamma spectroscopy here. If I suspect that on a gamma spectrum I have a line which is a consequence of the presence of Ge-78 - which is being produced via the neutron activation of a ...
0
votes
1answer
27 views

Is it possible to have neutron capture reaction induced by more than one neutron?

Is it possible to have neutron capture reaction induced by more than one neutron? I mean X(2n,...)Y. I think i saw some reactions like that before but cant remember the source. Thanks
0
votes
0answers
18 views

Can an excited nucleus capture a second neutron? [duplicate]

I am wondering if is it possible to have the following scenario: Nucleus captures neutron. Nucleus is excited but does not relax through decay but captures another neutron. Maybe it is possible if ...