[Gate-users] Phase Space as source

[Nada Fakhoury]

Dear all,

I am taunted by this questing for the last few days and I was  
wondering if someone has bumped into similar problems and may save me  
some trouble.

So I have produced a phase space file in Gate, which I wish to use as  
a source.
The question is whether the particles that are saved on it are  
reproduced in the specific direction they were "saved as", or whether  
a random angle is reassigned.

To get a better view on my question let me just say that I have  
designed a LINAC head and I take my phase space right before the jaws.  
Now when I run a simulation with the full geometry I get a dose  
profile that matches the jaws' opening, while when I use the phase  
space as a source, I get a  profile with double the dimensions. So my  
thought is that if a different angle was to be assigned par example to  
the photons originating at the center of the phase space plane, then  
since the distance from source is now smaller, it is logical that the  
dose profile would appear larger. Simple trigonometry.

So how do I check the angles of the particles that are produced from  
my phase space?

Thanks in advance for any tips!

Nada