The development of a high-energy (10Mev) neutron imaging system at Lawrence Livermore National Laboratory (LLNL) depends on a precision engineered rotating aperture and vacuum system for generating neutrons that are used for imaging dense objects. This subsystem is part of a larger system which includes a linear accelerator that creates a deuteron beam, a scintillator detector, imaging optics and a high resolution CCD camera. A rotating aperture is a device that allows the high energy pulsed beam to interact with deuterium gas in a gas cell and thereby create the neutrons used for imaging (see Figures 1-3). The gas cell is flanked by two metal disks that rotate at 4000 rpm. The disks have two 5mm holes and act as a rotating aperture when the holes line up with holes in the gas cell and allow the deuteron beam to pass through into the gas cell. When the holes aren't lined up, gas from the gas cell leaks past the disks and into a vacuum vessel.
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