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A 100 MeV proton beam of $10^{14}$ proton/s is perpendicularly incident on a rhodium foil 25 $\mu$m in thickness. Estimate the production rate of K and L x-rays(use the figure below).

enter image description here

So far I figured out from above the cross section for L x-rays to be $8\times 10^{2}$ barns and for K x-rays to be $1\times 10^{2}$ barns

I have the right answers for this one but I can't seem to figure out the right formula to use in order to arrive the given answer.

L $1.3\times10^{13}$ per second K $1.6\times10^{12}$ per second

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closed as off-topic by Kyle Kanos, Jim, Brandon Enright, Prahar, BMS May 14 '14 at 4:16

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Homework-like questions should ask about a specific physics concept and show some effort to work through the problem. We want our questions to be useful to the broader community, and to future users. See our meta site for more guidance on how to edit your question to make it better" – Kyle Kanos, Jim, Brandon Enright, Prahar, BMS
If this question can be reworded to fit the rules in the help center, please edit the question.

up vote 2 down vote accepted

To do this homework problem, you need to find the number of nuclei per barn in the foil.

If you read The Value of the Cross-Section Concept you will understand what to do.

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Thanks! I figured it out now. I'll make sure to give you points when I get at least 15 reputation points. – akino May 13 '14 at 15:27

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