  High-purity germanium crystals approximately 12 cm in diameter were grown in
a hydrogen atmosphere using the Czochralski method. The dislocation density of
the crystals was determined to be in the range of 2000 - 4200 cm-2, which meets
a requirement for use as a radiation detector. The axial and radial
distributions of impurities in the crystals were measured and are discussed. A
planar detector was also fabricated from one of the crystals and then evaluated
for electrical and spectral performance. Measurements of gamma-ray spectra from
Cs-137 and Am-241 sources demonstrate that the detector has excellent energy
resolution.
