Heavy Ion RFQ – Experimental Facility for Reactor Material Investigation under Irradiation
Development of new materials for future energy facilities with higher operating efficiency is a challenging and crucial task. However, full-scale testing of radiation hardness of reactor materials is quite sophisticated and difficult as it requires long session of reactor irradiation; moreover, induced radioactivity considerably complicates further investigation. Ion beam irradiation does not have such a drawback, on the contrary, it has certain advantages. One of them is high speed of defect formation. Therefore, it provides a useful tool for modeling of different radiation damages. Improved understanding of material behaviour under high dose irradiation will probably allow to simulate reactor irradiation close to real conditions and to make an adequate estimation of material radiation hardness. ITEP heavy ion RFQ HIP-1 provides accelerated beams of Cu, Fe, Cr ions with current up to 4 mA and energy 101 keV/n. The results of beam extraction line adjustment for experiments with reactor materials are presented. The construction of controllable heated target is presented as well. The first experiments will be started at the beginning of 2009.Also, the low energy experiments are carried on at the HIP-1 injector. The construction of target for low energy experiments is presented as well. The main objectives of this work are to study primary damage, cascade formation phenomena, phase stability and self-organization under irradiation. This research is carried out by means of tomographic atom probe and transmission electron microscopy.
Use of MeV energy ion accelerators to simulate the neutron damage in fusion reactor materials
Abstract This paper describes experimental techniques for irradiation of fusion reactor materials with MeV energy ions. The studies were conducted at the NRC “Kurchatov Institute” – ITEP. Two MeV-range linear ion accelerators were used for sample irradiation: the Heavy Ion Prototype (HIPr) accelerator with heavy ions and I-2 accelerator with protons. Target chambers of HIPr accelerator were modified to provide the simultaneous irradiation of four 10 × 10 mm2 samples at controlled elevated temperatures. Damage rates and profiles were calculated using the SRIM code. HIPr accelerator provided the damage of tungsten samples with 5.6 MeV Fe2+ ions at a rate of 0.05 dpa/h. I-2 accelerator was used to irradiate tungsten samples with 22 MeV protons to create a uniform damage profile at a depth of 0–400 μm with a rate of 5 × 10−7 dpa/h. Irradiation of tungsten samples with high energy protons causes generation of 183Re and 184Re with a half-life period of 70 and 38 days, respectively. Thus, the samples irradiated with a proton fluence of up to 1020 protons/m2 are subject to one year aging before manual handling.
Optical rotatory dispersion and absolute configuration—III
Abstract Optical rotatory dispersion measurements on pyrrolidine, piperidine, and tetrahydro-isoquinoline alkaloids indicate that the absolute configuration of the α-asymmetric center may be assigned directly from the dispersion curve, provided either that the nitrogen atom is not protonated, or that the compound contains a chromophore absorbing above 200 mμ.