Patent ID: 6445772
Filing Date: 2002-09-03
Classification: G21K

Abstract:
A multilayer grid containing alternate layers of an opaque or absorptive material and a transparent material for a neutron, hard X-ray, gamma-ray, imaging instrument containing a grid tray having openings to receive multilayer grids, the multilayer grid being a regular polyhedron having faces transparent to photons of interest, the polyhedron having two larger faces in the form of congruent polygons forming front and back surfaces of the polyhedron, remaining faces being smaller polygons separating the front and back surfaces a predetermined distance equal to the width of the two materials contained therein, the larger faces being shaped to form a multilayer grid fitting slidably within the grid opening in the grid tray, and the polyhedron containing a piston formed of a material transparent to photons of interest, which, through a drive shaft, compresses and retains the multilayers in place within the polyhedron, and which is allowed to remain in the polyhedron when, as a grid, the polyhedron is placed in the grid tray.