Hey /sci/ I'd like some input on the best way to defend a small structure from attack by a satellite based positronium annihilation gamma-ray laser. What is the most expedient and cost effective method for preventing the death of the occupants? Subterranean burial? Lead shielding? Something I'm not thinking of? Also how long after being attack by such a weapon should one wait before exposing themselves to residual radiation effects?

Thanks!