# Differential cross-section and scattering.

## Homework Statement

A beam of 0.38 MeV neutrons is incident on a 113Cd foil of thickness 1mm. The absorption
48
cross-section for 0.38 MeV neutrons is 5 barns. What is the fraction of neutrons absorbed by the foil?

## The Attempt at a Solution

I'm not sure whether I should treat this as scattering in a thick or thin foil and how the energy of the incoming particles is related to the total scattering of particles.

Thanks.

Related Advanced Physics Homework Help News on Phys.org
Hi! I tried using the formulae given in that webpage. Problem is I dont know where the kinetic energy of the neutron (0.38 MeV) comes in into that equation. Anyhow I still get the wrong answer..

Hi! I tried using the formulae given in that webpage. Problem is I dont know where the kinetic energy of the neutron (0.38 MeV) comes in into that equation. Anyhow I still get the wrong answer..

For scattering in a thin foil:

R = F σ n A dx

We have to find R/F and then to get fraction of neutrons absorbed by foil (1 - R/F)

We know what σ, n and dx are, but not A. I dont know why they give me the energy value of the neutrons...?

Please write what is n, A , etc..because many people use their own convention so better to write the key. Is A the mass number of target. ?
Did you miss anything in your question?
Okay i just made a simple calculation using the formula found in that website..
is your solution, i.e the fraction of neutron beam scattered is 0.023? (1-0.23)=0.977.
In fact i am sorry i also don't know why they have given the energy of beam.

Please write what is n, A , etc..because many people use their own convention so better to write the key. Is A the mass number of target. ?
Did you miss anything in your question?
Okay i just made a simple calculation using the formula found in that website..
is your solution, i.e the fraction of neutron beam scattered is 0.023? (1-0.23)=0.977.
In fact i am sorry i also don't know why they have given the energy of beam.

F = flux incident on target. (particles per m² per sec)

A = Total area of foil

n = number density of target atoms
σ = scattering cross section
dx = thickness of foil

Im having the exact same problem, I still cant figure it out.

Thanks.