  We present the use of a low background counting facility, equipped with a
p-type 80% relative efficiency HPGe detector, protected by active and passive
shielding, and large enough to count a 10" photo-multiplier tube (PMT). A
GEANT4 Monte-Carlo of this detector was developed and tuned to 3% accuracy. We
report the U, Th, and K contents in three different types of PMTs used in
current neutrino experiments, with accuracies of $\sim 10$ ppb for U and Th and
of $\sim 15$ ppm for K.
