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jack7992
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Homework Statement
A thin (1mg/cm^2) target of 48-Ca is bombarded with a 10-nA bean of alpha particles. A detector, subtending a solid angle of 2E-3 steradians, records 15 protons per second. If the angular distribution is isotropic, determine the total cross section, in mb, for the reaction. You can take the atomic mass of 48-Ca to be A= 48.
Homework Equations
The Attempt at a Solution
I know basically how to do this problem. I can calculate flux, number of scattering centers, etc. The only thing I am getting hung up on is the solid angle idea. From my understanding, this is basically saying that a detector with a solid angle of 2E-3 str detects 15 protons/sec., which is only a portion of the total deflected. I can get the differential cross section. My question is how do you get the total cross section. Do you just multiply by a str factor or something? Thanks a lot!