1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Solid Angle Rutherford Scattering

  1. Jan 8, 2015 #1
    1. The problem statement, all variables and given/known data
    derive an equation for the solid angle for a Rutherford scattering detector given a detcor window area of [itex]A[/itex] and a distance to the detector of [itex]D[/itex] for some scattering angle [itex]\phi[/itex] given that [itex]d\Omega =2\pi sin\phi d\phi[/itex]

    2. Relevant equations
    [itex]d\Omega =2\pi sin\phi d\phi[/itex]
    [itex]A=Dd\phi [/itex]
    3. The attempt at a solution
    integrating [itex]d\Omega =2\pi sin\phi d\phi[/itex] to get solid angle gives [itex]\Omega =\frac{2\pi A}{D}\int sin\phi d\phi[/itex] howver this gives a negative value due to the integral of sine and shouldn't soild angle be positive? Is this correct or am i missing a step? Thank You
  2. jcsd
  3. Jan 8, 2015 #2


    User Avatar
    Science Advisor
    Homework Helper
    2017 Award

    You sure this gives a negative value ? Can you show how you get it ? Bounds, primitive ?
  4. Jan 8, 2015 #3


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    That's dimensionally incorrect. You have an area on the left and a distance on the right. And the dϕ looks wrong.
    Shouldn't it be ##A = D^2d\Omega##?
    As BvU posted, your problem with the negative sign will resolve itself when you put in the bounds on ϕ.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted