Since this is not my area of expertise, I searched Google under the key words "Rutherford's gold foil experiment" to get these possible sources:
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In terms of "proof," you might want to read this article:
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.
I hope this helps. Thanks for asking.