Origin of the Reactor Antineutrino Anomalies in Light of a New Summation Model with Parametrized ß

We investigate the possible origins of the reactor antineutrino anomalies in norm and shape within the framework of a summation model where ß^{-} transitions are simulated by a phenomenological model of Gamow-Teller decay strength. The general trends of divergence from the Huber-Mueller model on the antineutrino side can be reproduced in both norm and shape. From the exact electron-antineutrino correspondence of the summation model, we predict similar distortions in the electron spectra, suggesting that biases on the reference spectra of fission electrons could be the cause of the anomalies.

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 in 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 content in three different types of PMTs used in current neutrino experiments, with accuracies of ~10ppb for U and Th and of ~15ppm for K.