Production of Neutron Transmutation Doped (NTD) Germanium Thermistors for CUORE*

CUORE is a cryogenic bolometer experiment designed to look for neutrinoless double beta decay in tellurium-130 in the inverted mass hierarchy region. The source/detector will consist of 988 TeO$_2$ crystals weighing a total of 740 kg, or 204 kg of Te-130. Each bolometer consists of a 5x5x5 cm$^3$ TeO$_2$ crystal, a silicon resistive heater, and a thermistor which measures the small temperature rise in the crystal when energy from a nuclear decay or background events is deposited. To achieve the required uniformity and concentration in the gallium and arsenic dopants in the thermistors, germanium wafers are neutron-transmutation doped by irradiation at a nuclear reactor. We will present the techniques developed to dope and test four 58 g high-purity germanium wafers with a diameter of 65 mm and thickness 3 mm to an absolute precision of 1\%.