Compton scattering photons per radian vs steradian at 150° and 90°

[abotiz]

Homework Statement

In an experiment there was found equal compton scattered photons per steradian in the direction 150* as in 90*

Homework Equations

What relation in number of scattered photons in 150* and 90* would you get if you define number of photons per radians instead?

The Attempt at a Solution

I feel that this one is easy, but I don't know how to start with this.

Thanks!

 

[tiny-tim]

hi abotiz!

(have a degree: ° )

be logical …

start with the definition …

what is the definition of steradian?

 

[abotiz]

$$\stackrel{d\sigma}{d\theta}$$=$$\stackrel{d\sigma}{d\Omega}$$*$$\stackrel{d\Omega}{d\theta}$$

where $$\stackrel{d\Omega}{d\theta}$$ = 2$$\pi$$sin$$\theta$$

so the answer is sin90/sin150 i.e = 2

Right?

Thanks

 

[tiny-tim]

hi abotiz!

(just got up :zzz: …)

$$\stackrel{d\sigma}{d\theta}$$=$$\stackrel{d\sigma}{d\Omega}$$*$$\stackrel{d\Omega}{d\theta}$$

where $$\stackrel{d\Omega}{d\theta}$$ = 2$$\pi$$sin$$\theta$$

so the answer is sin90/sin150 i.e = 2

Right?

Thanks

sorry, i don't understand that at all

what are you using as the definition of steradian?

 

[abotiz]

Hi!

I found that definition in the Literature we are using.

Seems to be derived from $$\sigma$$ = $$\int\stackrel{d\sigma}{d\Omega}$$*$$\Omega$$ ( total scattering cross section )

Anyways, I think my answer is right, perhaps the definitions we are using is based for a special case or something, which I don't know anything about

Thanks

 

[tiny-tim]

That's the formula for the integral of the differential cross-section (σ is ordinary area in m², Ω is angular area in steradians) …

where do radians come into it?

 

[abotiz]

Beats me.

But its not that weird, if you would take the derivative of that equation and divide both side with the differential angle, or what you call it ( dtheta) you would get the equation I used. Anyways, Thanks