A POLYCAPILLARY BENDING AND FOCUSING LENS FOR NEUTRONS

A glass polycapillary lens that both bends and focuses a cold neutron beam has been designed and constructed. The bender focuser guides part of the incident beam away from its line of sight and focuses it to a spot of width 0.65 mm at a distance 95 mm from the lens exit and 20 mm below the bottom edge of the beam path, with a gain of 20 in neutron current density. The neutron transmission characteristics of the lens have been determined with two types or position-sensitive detectors, a charge injection device, and an imaging plate. The lens has been test ed with prompt gamma measurements on a gadolinium shard and titanium f oil. (C) 1997 American Institute of Physics.