A neutron lens constructed with polycapillary glass fibers is used to
focus a 50x45 mm2 beam exiting a cold neutron guide onto a spot of 0.5
3 mm (full width at half maximum) with a current density gain of 80. T
he characteristics of the lens are presented. This lens is designed to
enhance the detection limit and lateral resolution for prompt gamma a
ctivation analysis using cold neutron beams.