[Gate-users] (no subject)

[bearboysj at sina.cn]

Hi, all gate users

I have a question about the source mac file of a CT scanner. 
when I choose to use the mac command as below in the source mac file:
/gate/source/xraygun/setActivity xxx. becquerel
I find the particles recorded on the PhaseSpace on the CT detector surface 
is less than expected. For example, I set the activity to 1000Bq, and run a 
time slice 1s, the expected photon number is 1000, but the photon number
recorded by the PhaseSpace is less than 1000.  I want to know why is that.
Thank you!
 
By the way,  I have control the geometry and material( set vacuum) 
to record all the photon emitted from the source.

Xiong Shou-Jian