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.
Report on ITEP MEVVA development
The MEVVA ion source (version ITEP-90) designed and constructed at ITEP is used at the injector of the heavy ion RFQ linac (TIPr-1) which has been built as a driver prototype for heavy ion fusion program. The source operates in a pulse mode. Pulse length was from 5 to 140 {mu}s, repetition rate is up to 1/2 Hz. The injection voltage is 50-70 kV. The modified version of the source with drift channel and electron gun has been named e-MEVVA. The first measurements of charge state distributions for e-MEVVA beam carried out by time-of-flight (TOF) method showed promising results. Copper ions with charge to mass ratio up to 1/3 - 1/5 has been detected. The more detailed investigation of beams generated by MEVVA and e-MEVVA have been carried out in the framework of the agreement with GSI. It has been planned to measure the beam parameters at operation regimes that are close to GSI injectors ones. The main requirements of GSI specifications are: (1) Charge to mass ratio 1/8, 1/24, 1/60 (2) Pulse length > 400 {mu}s (3) Repetition rate >5 Hz. In the framework of this agreement the following works have been done: (1) the new power supply unitsmore » for MEVVA and e-MEVVA have been designed and manufactured; (2) analyzing magnet has been installed between the injector and RFQ; (3) the measurements of CSD for MEVVA and e-MEVVA ion source have been carried out by both time-of-flight method (TOF) and magnet mass-analyzer.« less
90"-apart-stem RFQ Structure for Wide Range of Frequencies
At present, many different resonant RFQ structures for accelerating both light and heavy ions are successfully used. Usually they are divided into two well known groups: 4vane and 4-rod structures, each of them having its merits and drawbacks. In this paper a new resonant structure is considered, which combines the advantages of both. It may be seen as a 4-vane structure with holes (“windows”) in the vanes, or as a 4-rod one having stems located 90’ apart from each other and from the beam direction, Thus, changing the window size, such a structure can be modified from a typical 4-rod resonator, working at 50 MHz or less, to a typical 4-vane one, working at higher frequencies (up to 500 MHz) and having a better frequency distinction between operating and unwanted dipole modes, due to the magnetic coupling between neighbouring quadrants through the holes. It also should be noted that no voltage arises on the beam axis in the gap between end plate and electrodes, provided that horizontal and vertical windows have the same longitudinal position. Computer simulations with MAFIA codes are presented and compared with cold model measurements.