Physics Stack Exchange
Physics Stack Exchange

Questions tagged [neutrons]

The neutron is a subatomic particle, with no net electric charge and a mass slightly larger than that of a proton. It is a fermion of spin $\frac 1 2$; a hadron, that is it interacts strongly; and a nucleon, that is a crucial component of atomic nuclei.

The neutron is a subatomic particle, with no net electric charge and a mass slightly larger than that of a proton. It is a fermion of spin 1/2; a hadron, that is it interacts strongly; and a nucleon, that is a crucial component of atomic nuclei.

545 questions
3
votes
2 answers

What is difference between fast neutrons and thermal neutrons?

Recently i was reading about neutron absorption by metals. But there are always two different categorizes for thermal neutrons and fast neutrons. I don't understand what difference between them! Most importantly i want know fast neutrons or thermal…
A.M.M Elsayed 马克
  • 527
1
vote
3 answers

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 which bring out biological damage. Why? You know…
user28936
  • 926
1
vote
1 answer

Neutrons generator

How free neutrons with a certain kinetic energy are produced in laboratory? For example in nuclear fission $n$ free neutrons are produced, are there other methods?
Salmon
  • 901
1
vote
0 answers

ultracold neutron captured inside fullerene molecule

I wonder if one could capture an ultracold neutron (energy below 180 neV) inside an equally cold C60 molecule to obtain a composite molecule n@C60. It is known that neutrons with this very low temperature reflect fully off a polished graphite…
Donkey
  • 21
  • 2
1
vote
1 answer

Why fast neutrons for breeder reactor but slow neutrons for regular light water reactor?

Water is used as a moderator to slow down neutrons in a light water nuclear reactor. By slowing down the neutrons they have more of a window to strike fission ready nuclei thus promoting the self perpetuating chain reaction when more neutrons are…
0tyranny0poverty
  • 1,056
1
vote
1 answer

What feature of the Beryllium nucleus makes it such a good source of neutrons when hit with alpha radiation

Be is often used as the neutron gun to supply neutrons to initiate nuclear reactions, particularly nuclear chain reactions. I always presumed the nucleus of lighter elements to be more stable than the heavier ones. Be with an atomic number of 4,…
0tyranny0poverty
  • 1,056
1
vote
1 answer

what really happens in the resonance region in neutron radiative capture?

Why does the cross section show anomalous peaks over arange of energies known as resonance region in neutron radiative capture process?
Sabeeka Nazeer
  • 119
0
votes
2 answers

Why is a neutron stable inside a magnetic bottle?

Free neutrons are not stable. But inside a magnetic botlle they become stable. Why?
Japha Nakhão
  • 19
0
votes
0 answers

Thermal or fast neutrons are used for adding neutrons to atomic nuclei?

I understand that there is difference between thermal and fast neutrons according to their energy. Now, if one wishes to add neutrons into atomic nuclei, it should be easy as neutrons are neutral, so they can pass by the electron clouds and they…
A.M.M Elsayed 马克
  • 527
0
votes
0 answers

Calculating neutron decay rate

In this paper, it is reported that the neutron decay rate is: $$W=\dfrac{m_e^5c^4}{2\pi^3 \hbar^7}|\mathcal{M}| f$$ where $\mathcal{M}$ is the matrix element and $f$ is a factor space statistical factor and $m_e$ is the electron mass. The paper…
mattiav27
  • 1,325
0
votes
1 answer

Differences between neutrons from electron capture and positron emission

I imagine that the mass of a neutron from $\beta^{+}$ decay is about $2.5 Em$ lighter than one obtained by electron capture. Is that so? Can you tell me how wide neutron mass can range, and if there are other differences? In particular I'd like to…
user104372
0
votes
2 answers

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?
user2800708
  • 942
0
votes
1 answer

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
Don el Fuego Integer
  • 3
0
votes
1 answer

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 force the neutron experiences in a magnetic field…
linuxfreebird
  • 2,107