Consistent gamma polarization in positron annihilation

Hello everyone,
I’m trying to implement a Compton polarimeter in Geant4, in which the gamma source is a Na22 radioactive sample (similar to the old Wu-Shaknov experiment). Using the standard radioactive decay process implementation, I noticed that the two 511 keV gammas from the annihilation of the positron have a null polarization (aka (0,0,0)).
Is there any package/setting/option that gives the possibility to obtain “realistically polarized” gammas from this physical process?

Thanks in advance


if you simply put as a primary particle e+ of zero energy you will get 2 gammas with correct polarisations. This will be for any Physics List.