0000000000312334
AUTHOR
F. Delaunay
Determination of consensus kQ values for megavoltage photon beams for the update of IAEA TRS-398
The IAEA is currently coordinating a multi-year project to update the TRS-398 Code of Practice for the dosimetry of external beam radiotherapy based on standards of absorbed dose to water. One major aspect of the project is the determination of new beam quality correction factors, kQ, for megavoltage photon beams consistent with developments in radiotherapy dosimetry and technology since the publication of TRS-398 in 2000. Specifically, all values must be based on, or consistent with, the key data of ICRU Report 90. Data sets obtained from Monte Carlo (MC) calculations by advanced users and measurements at primary standards laboratories have been compiled for 23 cylindrical ionization chamb…
New insight into δ-Pu alloy oxidation kinetics highlighted by using in-situ X-ray diffraction coupled with an original Rietveld refinement method
Abstract The reactivity of a δ-Pu alloy was studied under dry oxygen at different temperatures. Phase analysis has shown the presence of α-and β-Pu2O3, PuO2, as well as the destabilisation of the δ-phase. The oxidation kinetics were studied using in-situ X-ray diffraction coupled with an original method of Rietveld refinement enabling an individual monitoring of the growth of each oxide. The results have evidenced a parabolic stage resulting from the thickening of the α-Pu2O3 layer, in which a compressive stress state develops. This stage is followed by the linear growth of a porous PuO2 scale.
Energy damping and intermediate-velocity fragment emission in peripheral Kr+Au collisions at 43 MeV/u
Abstract Triple and four-fold coincidences among fragments have been measured in the reaction 84 Kr+Au at 43 MeV/u. All events showing the projectile-like nucleus and fission fragments of the target-like nucleus, and all events with one additional intermediate-velocity fragment, were analysed in the frame of a dissipative collision and a participant-spectator model. The mechanism is basically that of a dissipative collision but the emission of the intermediate velocity fragment by the target differs from an equilibrated evaporation.