A View of the Present Status and Future Prospecis of High Purity Germanium

The present state of our knowledge of the properties of high purity germanium is reviewed. The role of excess vacancies, oxygen and high dislocation density in producing trapping in detectors is discussed. By the application of Fourier Transform Spectroscopy, the major impurities have been identified and aluminum has been found to be the dominant one in most crystals. Analysis has shown that the principal source of aluminum is the polycrystalline starting material. The material problems related to detector fabrication are surveyed and a spectrum taken with a 43 cm3 coaxial detector is presented. It is concluded that the important problems of material development are well delineated but that their solutions will require intensified effort.