Showing papers by "R. K. Fisher published in 2003"

Neutron images recorded with high-resolution bubble detectors

Abstract: Neutron images have been successfully recorded with “gel-type bubble detectors.” 14 MeV fusion neutrons emitted from laser-irradiated inertial confinement fusion targets formed coded images in proof-of-principle experiments conducted at the OMEGA laser facility. In the detector, small (∼50 μm diameter) bubbles form when high-energy neutrons collide with the detector material. Each collision produces only one bubble whose position can be determined with a precision of better than 25 μm. Additionally, bubble detectors are insensitive to x-ray and gamma-ray background. For these ride-along experiments, bubble detectors were simply inserted between the imaging aperture and the scintillation detector of the primary experiment. Recorded images for high-yield (6×1013) targets show the bubble detector’s potential for high resolution. More complex “liquid” bubble detectors are expected to have efficiencies of ∼1% (versus 0.001% for gel-type) while maintaining the desirable characteristics of the gel-type units. Th...