Abstract by Chase Vanfleet
Physics and Astronomy
Miniaturized x-ray collimators through tungsten infiltration of carbon nanotube microstructures
Collimators in X-ray sources and detectors have presented the problem of being overly massive and bulky and therefore hindering to rapidly shrinking instrument and detector designs. Through carbon nanotube microfabrication with vertically aligned nanotube forests, collimators can be miniaturized by several orders of magnitude without reducing the acceptance angle-limiting aspect ratio.
The degree to which these collimators attenuate X-rays is dependent on the thickness of tungsten deposited on the nanotubes through a tungsten ALD process. It has been seen that upward of 35nm of tungsten infiltration are required to attenuate 8 keV X-rays to a negligible intensity. Though it is difficult to maintain structural uniformity in collimators with very high aspect ratios, which may limit the possible acceptance angles of collimators, tungsten-carbon nanotube microstructures have been found to be a plausible alternative to conventional low-energy X-ray collimators.