High precision grids for neutron, hard X-ray, and gamma-ray imaging systems

US6445772B1 · kind B1 · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventor

• Jonathan Campbell · Harvest, US

Key dates

• Filing date: May 30, 2001
• Grant date: Sep 3, 2002
• Expiry date: May 30, 2021

Classification

• Technology area (CPC G): Physics
• CPC primary: G21K1/02
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

Fourier telescopes permit observations over a very broad band of energy. They generally include synthetic spatial filtering structures, known as multilayer grids or grid pairs consisting of alternate layers of absorbing and transparent materials depending on whether neutrons or photons are being imaged. For hard x-rays and gamma rays, high (absorbing) and low (transparent) atomic number elements, termed high-Z and low-Z materials may be used. Fabrication of these multilayer grid structures is not without its difficulties. Herein the alternate layers of the high-Z material and the low-Z material are inserted in a polyhedron, transparent to photons of interest, through an open face of the polyhedron. The inserted layers are then uniformly compressed to form a multilayer grid.