# Homework Help: Neutron collision in quantum mechanics

1. Oct 18, 2014

### Frank Einstein

1. The problem statement, all variables and given/known data

Good morning or afternoon. My quantum physics teacher has given me a task: Given a neutron beam of mass 1.27*10^-27 kg and known energy E impacts on a lineal chain of atoms with a known distance between two of them l. A detector intercepts the wave diffracted an angle o.

I have to a) describe qualitatively what happens at the detector as a function of the energy and b) for E=E1, find l as a function of E1 and o. Then find it for the numerical values o= 30 degrees and E1= 1.3*10^-20 J.

I have a drawing, but I don’t know how to post it.
2. Relevant equations

E=(mN^2*C^4+PN^2*C^2)^(1/2)
P= h/wavelength
E= h*frequency
3. The attempt at a solution

The only thing I can think of is to think that the neutrons are waves instead of particles, these waves reflex on the chain of atoms and keep moving with a certain angle. The energy of the neutron is E=(mN^2*C^4+PN^2*C^2)^(1/2) and P= h/wavelength. So that, E= (mN^2*C^4+(h/wavelength)^2)^(1/2), then I find the wavelength and say that is smaller than a atomic radius, so that’s why the collision happens.

2. Oct 23, 2014