Vandermeersch, B. McCown, T. Howells, W. Bar-Yosef, O. Ronen, A.
Recent African origin of modern humans
Deformation and sliding
Aim: The modern radiotherapy techniques impose new challenges for dosimetry systems with high precision and accuracy in in vivo and in phantom dosimetric measurements. The knowledge of the basic characterization of a dosimetric system before patient dose verification is crucial. This incites the investigation of the potential use of nanoDot optically stimulated luminescence dosimeter OSLD for application in radiotherapy with therapeutic photon beams. Materials and methods: Measurements were carried out with nanoDot OSLDs to evaluate the dosimetric characteristics such as dose linearity, dependency on field size, dose rate, energy and source-to-surface distance SSD , reproducibility, fading effect, reader stability, and signal depletion per read out with cobalt 60 Co beam, 6 and 18 MV therapeutic photon beams. The data acquired with OSLDs were validated with ionization chamber data where applicable. Results: Good dose linearity was observed for doses up to cGy and above which supralinear behavior.
ELECTROCHEMISTRY Principles, Methods, and Applications
Desert Archaeology crew chief Caleb E. Ferbrache explains how electrons trapped in rock can be used to date archaeological deposits—and why, unlike the more familiar carbon dating, OSL allows dating in the absence of preserved organic material. Most people know that archaeologists regularly use carbon also called radiocarbon to date materials they find.
Optically-Stimulated Luminescence is a late Quaternary dating technique used to date the last time quartz sediment was exposed to light. As sediment is transported by wind, water, or ice, it is exposed to sunlight and zeroed of any previous luminescence signal. Once this sediment is deposited and subsequently buried, it is removed from light and is exposed to low levels of natural radiation in the surrounding sediment. Through geologic time, quartz minerals accumulate a luminescence signal as ionizing radiation excites electrons within parent nuclei in the crystal lattice.