Doppler broadening as a probe of the chemical environment following oxygen-14 decay

A search for the Doppler broadening following the beta decay of oxygen-14 was conducted with high resolution gamma spectroscopy on the 2313 keV gamma ray. Such a broadening should signal the mass of the labeled molecule and the nature of the stopping medium. Oxygen-14 labeled H2O, O-2 and CO2 trapped on solid soda lime were investigated. No broadening was observed beyond the 1.65 keV instrumental resolution of the Ge detector, monitored by the unbroadened 2319 keV isomeric transition in Nb-90 decay

Hexamodal Imaging with Porphyrin-Phospholipid-Coated Upconversion Nanoparticles

X1110084sciescopu