[en] The Cryogenic Dark Matter Search (CDMS) utilizes large mass, 3-inch diameter x 1-inch thick target masses as particle detectors. The target is instrumented with both phonon and ionization sensors, the later providing a ∼1 V cm^-1 electric field in the detector bulk. Cumulative radiation exposure which creates ∼200 x 10⁶ electron-hole pairs could be sufficient to produce a comparable reverse field in the detector thereby degrading the ionization channel performance, if it was not shielded by image charges on the electrodes. To study this, the existing CDMS detector Monte Carlo has been modified to allow for an event by event evolution of the bulk electric field, in three spatial dimensions. Surprisingly, this simple model is not sufficient to explain the degradation of detector performance. Our most recent results and interpretation are discussed.

[en] At the 88-Inch Cyclotron at the Lawrence Berkeley National Laboratory we have developed an intense low energy ¹⁴O ion beam. During the last development run, an average beam intensity of 2x10⁷ particles per second (pps) was achieved with a peak intensity of 3x10⁷ pps. The ¹⁴O will be used to measure the shape of the beta decay spectrum of the Garnow-Teller branch as a test of the Conserved Vector Current Hypothesis. The half-life will also be measured and used to determine the Vud element of the Cabibbo-Kobayashi-Maskawa mixing matrix

[en] We present results on quasidiffusion studies in large, 3 inch diameter, 1 inch thick [100] high purity germanium crystals, cooled to 50 mK in the vacuum of a dilution refrigerator, and exposed with 59.5 keV gamma-rays from an Am-241 calibration source. We compare data obtained in two different detector types, with different phonon sensor area coverage, with results from a Monte Carlo. The Monte Carlo includes phonon quasidiffusion and the generation of phonons created by charge carriers as they are drifted across the detector by ionization readout channels.