A large HPGe detector for the non-destructive radioassay of an   ultra-low-background counting facility
  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. 
M. Fechner and C. Henson and J.Gaffiot and T. Lasserre and A.   Letourneau and D. Lhuillier and G. Mention and Th. A. Muelle...
physics.ins-det nucl-ex