Re: angular effect

[Matthew Shepherd <mashephe@indiana.edu>]

Hi Blake,

These plots are interesting and certainly something we should explore  
further.  It looks like the energy dependent (floor in this fit) is  
still dominant.  I assume the difference between the plots is  
fraction of energy in module vs. fraction of incident energy.  I'm  
afraid that this effect is probably correlated with the energy  
dependence, so we might not model it correctly by taking slices.  We  
may want to consider a coarse 2-D fit to sigma_f / f.  If we come up  
with a crude parametrization, this can be implemented easily in the  
MC by making the assumption that photons originated from the target  
and thus the true z position (recorded in the MC) can be used to  
determine the angle.  (It is also possible that the true incident  
angle can be passed up in the MC, but this is beyond my skill level!)

-Matt


On Jul 18, 2007, at 4:33 PM, Blake Leverington wrote:

> Hi Matt,
>
> I ran a simulation of the module for a 150 MeV (one for 650 MeV is  
> still running) with a flat distribution over sin(theta) to see the  
> effect on the sampling fraction since the sampling frequency  
> decreases with sin(theta). I've attached a couple of plots that  
> show the effect.
>
> -Blake<2p_samfracEmod_sintheta.gif><2p_samfrac_sintheta.gif>