Explaining Cross-Section, Diff. Cross-Section, & Solid Angle

[schattenjaeger]

well I can follow the math and derive the things I'm about to ask about and do problems asked of me but I'm kinda missing something, I guess

Can someone just give me a fairly layman's explanation of: cross-section, differential cross-section, and a solid angle? Those are all things I thought were something else and trying to look deeper into it just confuses me. Like, if the differential cross section was what I thought it was it'd behave differently than it does, which means I'm thinking of it wrong:(

 

[Andrew Mason]

well I can follow the math and derive the things I'm about to ask about and do problems asked of me but I'm kinda missing something, I guess

Can someone just give me a fairly layman's explanation of: cross-section, differential cross-section, and a solid angle? Those are all things I thought were something else and trying to look deeper into it just confuses me. Like, if the differential cross section was what I thought it was it'd behave differently than it does, which means I'm thinking of it wrong:(

Cross -section is a measurement of the area that the incoming particle must strike in order to deflect at any angle within a given range (ie it will deflect within a particular solid angle). The differential cross section is the area for which the incoming particle will deflect at a particular angle.

The cross-section is obtained by integrating the differential cross-section over all angles within the given range.

For help on tricky solid angles, http://en.wikipedia.org/wiki/Solid_angle" .

AM