Question

A beam of neutrons, 0.29 eV kinetic energy and 105 s−1 intensity, bombards a foil of 235U 0.1 kg/m^2 thickness. Calculate the number of fission reactions occurring per second in the foil, knowing that the fission cross section at the given neutron energy is 200 b. Need all computations for the final answer please.

Answer 1

Please follow up in case of any queries. I will be happy to help in the comments.

Reaction rate is given by

where is the cross-section at the relevant beam energy (lab frame).

Here is the Avogadro number

Substituting gives

So the Rate turns out at about 32 atoms per minute.

You may look up http://courses.chem.indiana.edu/c460/documents/sec15-reactions.pdf which gives a wider perspective on this and other closely related topics which you may enjoy looking up.

Please hit the thumbs up if you like my work.