Using GPS to simulate be the X-ray tube source

Hi all,

I want to simulate the relation between doserate and distance of my system.
Namely, the structure is X-ray tube and dosemeter. I change the distance between X-ray tube and dosemeter.

I already have spectrum of X-ray tube and I have many doserate of different distance.

My question is I should change photon count of spectrum or beamNumber to meet the measurement result?

Best regards,


Dear @allen_cheng
You question is a Pgysics one.
If your simulation is correct and the spectrum used is representative of the X-ray output, you just need to increase the beam (number of initial history) to have your result converge. But if you are getting something not in the range of the expected result (including error), you might need to check your code (energy, treshold, model, …).

take a look to this paper. maybe it can be helpful

Dear idrissi,

Thanks for your information.
Unfortunately, it does not provide code. I will try to contact the author to get more information.

Dear guembou,

Thanks for your reply.

When I increase the beam number, the dose will increase. Therefore, I can increase the beam number to achieve the same dose that I measure by dosemeter.

Based on my experience ( using visible light tracing software), I can increase the beam number to reduce the error.

I have a few questions:

  1. Do you know how to obtain the error of my Geant4 simulation?

  2. In the Geant4, I increased the beam number, and the sample abortion dose increased. I guess I could not increase the beam number to reduce the error.
    If I want to decrease the error, how many parameters can be used to reduce the error?