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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).

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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 the Enchanter, Brandon Enright, Prahar, BMS May 14 '14 at 4:16

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1 Answer 1

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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