Lorentzian line shape function

[Carnot]

Hi

I have a problem where the flux of a particle beam is measured using a (nearly) perpendicular laser beam and a photomultiplier.


I have a function looking like this:

L($\nu$) = $\frac{\gamma/2}{(\nu - \nu_0 + kv)^2 +(\gamma^2/4)}$

I suppose this is a Lorentzian lineshape function, but I have never seen it with the kv term.
Does anyone know what the kv term means in the equation?

Is it perhaps because the laser beam is on nearly perpendicular to the particle beam, and one therefore have to take doppler broadening into account?

Hope someone can help me, thanks

 

[Rajini]

Hi,
I think you took that Lorentzian function from some software manual. kv, i guess the increment for x-axis.
I guess, to consider also the Doppler broadening one can add some factor to line width, i.e. $/gamma$ (not kv).