Thanks a lot. Thank you for your response, it was very helpful to me.
I have followed as you adviced. I found that the cylindrical volume source created using BEAMPOS-type CYLI-VOL turned into a point source after adding SPOTBEAM. How can I solve this problem? My intention was to create a cylindrical volume source.
The issue same as Combination of cylindrical source and spectral sampling - #2 by horvathd
However, I dont‘t’ know how to “implement the cylindrical sampling manually”