Heterogeneous Amorphization of Cd Implanted GaAs at Room Temperature

Amorphization of GaAs implanted with Cd in the dose range of 2 x 10$\text{}^{13}$-1.2 x 10$\text{}^{14}$ ions/cm2 and the energy range of 20 to 180 keV at room temperature has been investigated. The degree and the depth distributions of postimplanted damage were measured by using RBS technique. The critical dose for each Cd-ion energy was determined. The amorphization models have been discussed. The results obtained are in agreement with theoretical predictions supporting heterogeneous amorphization of Cd-implanted GaAs at room temperature

Damage Production in As Implanted GaAs1−x\text{}_{1-x}Px\text{}_{x}

Post-implantation damage in GaAs$\text{}_{1-x}$P$\text{}_{x}$ compounds (x = 0, 0.15, 0.39, 0.65, and 1) implanted with 150 keV As ions in the dose range 1 × 10$\text{}^{13}$ -8 × 10$\text{}^{13}$ cm$\text{}^{-2}$ at 120 K was investigated. The depth distribution of damage and the degree of amorphization were measured by Rutherford backscattering 1.7 MeV He$\text{}^{+}$ channeling technique. The critical damage dose and the critical energy density necessary for amorphization were determined. It is shown that GaAsP is easier to amorphize (lower critical damage dose) than the binary crystals (GaAs, GaP) at low temperatures

Analysis of the accumulation of radiation damage in selected crystals

International audienceDamage accumulation in SiC and MgAl2O4 was interpreted in the framework of the multi step damage accumulation (MSDA) model. The concept is based on the assumption that damage build-ups occur in several stages, each step being triggered by the destabilization of the current structural organization of the material. The analysis of the damaging process may thus be regarded as an identification of the current structure at each subsequent step of the damage build-up and of the forces leading to the destabilization of current structure. The analysis of mechanical properties provides a useful tool for this purpose by allowing the recognition of the mechanisms of phase transformations and helping to clarify the detailed structures of irradiated materials. (C) 2008 Elsevier B.V. All rights reserved

Radioactivity distribution at MAFF

A detailed account on the distribution of radioactive nuclei in the vacuum system of the planned Munich Accelerator for Fission Fragments (MAFF) located at the FRM-II research reactor is presented. Tools used for the simulation of spacial and temporal distribution of radionuclides are explained. The latter allows for a detailed activity budget as well as estimates for the mass-separated ion yields at MAFF. Additionally, a concept to reduce the activity release from the MAFF slit system due to surface sputtering is presented. It is shown, that the use of low-density carbon foam, as a surface coating, reduces sputtering by orders of magnitude