# Homework Help: Scattering Vs Absorption Crossection

1. Jun 22, 2008

### therimalaya

What is the difference between Scattering Crossection and Absorption Crossection in nuclear reaction crossection?

"Arsenic $$As^{33}_{75}$$ has an absorption cross section for thermal neutrons of 4.1 b and a scattering cross section of 6 b, its density is 5.73 gm per cm cube. A beam of thermal neutrons is passed through a slab of arsenic 2 cm thick. By what fraction is the intensity of the beam reduced? [Avogadro Constant=6.023 x 10$$^{23}$$ mole$$^{-1}$$ and 1 b=10$$^{-24}$$ sq cm.]"

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2. Jun 22, 2008

### malawi_glenn

crossection is the probability for an even to occur, the event can be inelastic scattering, elastic scattering, absorption, etc.

So it is just a measurment of the probability for an event, the larger crossection - the more likley. The units of crossection is area.

Now this a HW-related problem, and I encourage you to google/ search your book, for the experimental definition of crossection, and then give it a try yourself, then we will help you.