Z.E., some students and I placed two PMTs inside a dark box and built a shield hut around it. The box is sitting on the floor under the stairs to the beam-right side of the BigBite detector stack.
There is at minimum 3--4" of lead on all sides of the toolbox + 6" of concrete bricks.
Inside the dark box are two PMTs:
5" XP4578: Signal on PP36
HV(+) 2002: slot 13.11
3" XP4318: Signal on PP35
HV(-) 2002: slot 10.11