Papers by Keyword: Krypton

Abstract: Transmission electron microscopy (TEM) characterizations were carried out on a set of UO₂ thin foils previously implanted at room temperature with 400 keV Xe²⁺ and 250 keV Kr²⁺ ions at the fluence 7.10¹⁵ at.cm^-2 (equivalent to 1 at.%/at. UO₂). The experiment was devoted to the study of the evolution of the fission gases bubbles populations with increasing temperature. Annealings were performed in the laboratory furnace at 600°C, 800°C, 1000°C for 12h, 1400°C for 4h and 1500°C for 2h under Ar-5%H₂ atmosphere. For each annealing condition and for as-implanted specimens the bubble population has been characterized in size and number density. A comparison between Xe and Kr has been done that showed a similar behaviour. Globally, from the as-implanted sample to the 1500°C annealed, the bubbles growth phenomenon and the microstructure evolution with temperature was put in relieve.

Abstract: The influence of the irradiation with neutrons, Kr+ (245 MeV) and Bi+ (710 MeV) ions on the optical and electrical properties of high-resistivity, high-purity 4H-SiC epitaxial layers grown by chemical vapor deposition was investigated using photoluminescence and deep-level transient spectroscopy. Electrical characteristics were studied using Al and Cr Schottky barriers as well as p+-n-n+ diodes fabricated by Al ion implantation on this epitaxial layers. It was found that both "light" neutrons and high energy heavy ions introduced identical defect centers in 4H-SiC. So, even at extremely high density of the ionization energy of 34 keV/nm, typical for Bi+ ion bombardment, damage structure formation in SiC single crystal is governed by energy loss in elastic collisions.