I am trying to model gamma ray emission around Pulsar. Similar model as in paper "Johannesson, Porter & Moskalenko, The ApJ, 879:91 (2019)" about Geminga.
The question is where in the code/galdeffile can I find option to change the parameter D_z - diffusion coefficient in SDZ (slow diffusion region)? This parameter occurs in the formula 3 from aforementioned paper, here is the image with this formula where one can find this parameter D_z:

I found out an answer and maybe for someone it will be interesting.

"D_z" coefficient are obtaining from multiplying of "D_0" to some specified number. In galdef file this number called "Dxx_bubble_fraction".
For example:

D_z = D_0 x Dxx_bubble_fraction