In an old thread discussing psykers and their powers, TS Luikart stated that "The Imperium (along with many Xeno races) have a number of materials / wards that can block psykers from just waltzing in and possessing the local Planetary Governor for kicks."
SPOILERS for Purge the Unclean ahead!
In Rejoice for You Are True, there were some rooms with "psi-shielding" around which any psykers felt their connection to the Warp drop away to zero. I got the impression from reading this that this was not particularly unusual, and had no resemblance to the xeno-tech circuitry encountered earlier.
But I can't find any rules for this anywhere. Wards, yes. They seem only to grant the wearer some protection against direct effects. Null rods, sure. Very rare things, but with a limited range and they do not completely block a psyker.
So what would the paranoid, witch-hating planetary governor do?
How can he get in touch with the architect of the Alabaster Court to order some of that 100% psi-blocker?