Slow Pulses from Germanium Detectors

Slow pulses from various types of Ge(Li) detectors, i.e., a planar, a coaxial, a thin p+-contact planar, and a ´back-to-back´ double planar detector, have been studied by using a gamma-ray scanning technique and a risetime selector. A large and abrupt increase in the counting rates of the slow pulses were observed when the n+-i and the i-p boundaries of these detectors were irradiated by a collimated gamma-ray beam. Slow pulses contributed to background counts in the pulse height distributions. Slow pulses from a deeply depleted n+-p detector made from a high-purity p-type germanium crystal were also investigated.