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.
Commissioning of ITEP 27 MHz Heavy Ion RFQ
MHz heavy ion RFQ designed for acceleration of ions with charge to mass ratio of 1/60 up to energy of 110 keV/u has been built in ITEP (Moscow). The RFQ is the realization of proposed in ITEP new resonant structure. The computer simulation showed that the structure provides uniform field distribution and high shunt- impedance. This allows to consider it as one of the best choice for intense heavy ion linac. The main goal of the work was experimental investigation of the structure parameters and dynamics of intense beam. At the same time this RFQ is intended to the research program on the heavy ion beam interactions with dense plasma. The limited financial resources required the development of simple construction of the RFQ using cheep materials. However it must to provide the radiotechnical parameters close to the simulated one and use RFQ as experimental installation. The experience of the construction has shown that it was succeeded to build relatively cheep structure keeping good mechanical stability, large frequency separation of the operating mode and uniform focusing field distribution. The first accelerated ions of Cu 2+ at RFQ output were obtained at the end of 1999. The results of the first beam experiments are reported.
Monte Carlo simulations of magnetovolume instabilities in anti-Invar systems
We perform constant pressure Monte Carlo simulations of a spin-analogous model which describes coupled spatial and magnetic degrees of freedom on an fcc lattice. Our calculations qualitatively reproduce magnetovolume effects observed in some rare earth manganese compounds, especially in the anti-Invar material YMn2. These are a sudden collapse of the magnetic moment which is connected with a huge volume change, and a largely enhanced thermal expansion coefficient.