When a very good planar Ge(Li) detector (3.8 cm2× 9 mm, ∼77°K, ∼1 kV/cm) was irradiated by a slit‐collimated137Cs &ggr;‐ray beam (slit width, ∼0.25 mm) incident parallel to then+‐iand thei‐pjunctions, a large and abrupt increase in the relative counting rate of slow rising pulses was observed near the two junctions. The slow pulses had much longer rise times (> 0.5 &mgr;sec) than those of the normal fast rising pulses whose rise times were determined by the transit times of the carriers.