Biotechnologically produced chitosans with nonrandom acetylation patterns differ from conventional chitosans in properties and activities
Sruthi Sreekumar, Jasper Wattjes, Anna Niehues, Tamara Mengoni, Ana C. Mendes, Edwin R. Morris, Francisco M. Goycoolea & Bruno M. Moerschbacher
Radiography is non-destructive imaging for engineering, medical diagnostics, airport security checks, and decontamination activities in nuclear plants. Inorganic scintillators are phosphor materials that convert radiation into visible photons with high luminescence and fast response, and scintillators with a few tens of micrometers thickness can improve sensitivity in radiation detection and imaging. To date, a production method for thick film scintillators is a time and cost consuming way of slicing and poshing bulk single crystals and transparent ceramics. Here, the chemically vapor deposited Ce3+-doped Lu3Al5O12 thick film scintillators (CVD-Ce3+:LuAG) with a thickness of 1–25 μm were produced at deposition time of 1–30 min. Numerical simulations indicated the penetration depth of α-particle in Ce3+:LuAG is 12.8 μm, and the 14-μm-thick CVD-Ce3+:LuAG showed highest light yield (31,000 photons 5.5 MeV−1), superior to the commercial Ce3+:LuAG single crystal scintillator (21,000 photons 5.5 MeV−1). In the X-ray radiograph taken with CVD-Ce3+:LuAG as a scintillation screen, 5-μm-width bar of metal microgrids can be identified. Vapor deposition technique can be a novel high-throughput production way of a thick film scintillator which is in a micrometer-thickness effective to converting radiations into photons for sensitive α-emitter detection and high-resolution X-ray imaging.
chitosan, biopolymers, DP,