[How to distribute gold nanoparticles isotropically in a sphere volume]

Dear, Geant4 users and experts,

Hello. I am a beginner of Geant4.
I am studying about mechanism of nanoparticle-aided radiotherapy.
In this study, I would like to distribute gold nanoparticles (e.g., diameter: 50 nm, type: sphere) isotropically in a sphere volume (i.e., specifically, if we define r_a and r_b as inner and outer radius of sphere volume, respectively, I would like to distribute the nanoparticles in the volume between r_a and r_b)

I think, if I define one gold nanoparticle, then, I would distribute the particles using “G4PVReplica” class. However, due to a number of particles (e.g., 1.4 X 10^5 GNPs), it might be a very time-consuming and unproductive work.

Thus, I would like to ask whether there are any other ways to distribute the nanoparticles without using the “Replica” class. If it is, could you share your knowledge ?

Thank you for your reading.^^

Hi Leeronaldo,

Did you try GPS under Geant4? You can find example macros from here : http://hurel.hanyang.ac.kr/Geant4/Geant4_GPS/reat.space.qinetiq.com/gps/examples/examples.html

Dear mtkaplanoglu,

Most of all, thank you for your reply.^^
Unfortunately, the nanoparticles I would like to build in the simulation are not particle source.
it is like an absorb material which other particle source has to pass through.(even though it generates a number of secondary electrons through interactions with other particle source)
Thus, I think your examples for general particle source would not be applied to my case.
However, again, thank you for your response.^^

Thank you for your reading.
Have a nice day!~~^^

Hello. Did you find the answer? how to do it?
I am also interested in this question …

A collaborator and I have wrote a class “FastAerosol” for efficiently simulating particle transport through aerosols consisting of many particles. This class has recently been accepted as an advanced example by Geant4 (https://github.com/Geant4/geant4/pull/11) and should be available soon (it is currently available in release 10.7-beta).

Hopefully this helps!

In case the the aforementioned FastAerosol class was interesting, the code and a manuscript comparing this class to standard methods in terms of simulation time and memory load is available on arXiv (https://arxiv.org/abs/2008.01236).