RESUMEN
Radioactive Ion Beams play an increasingly important role in several European research facility programs such as SPES, SPIRAL1 Upgrade, and SPIRAL2, but even more for those such as EURISOL. Although remarkable advances of ECRIS charge breeders (CBs) have been achieved, further studies are needed to gain insight on the physics of the charge breeding process. The fundamental plasma processes of charge breeders are studied in the frame of the European collaboration project, EMILIE, for optimizing the charge breeding. Important information on the charge breeding can be obtained by conducting similar experiments using the gas mixing and 2-frequency heating techniques with a conventional JYFL 14 GHz ECRIS and the LPSC-PHOENIX charge breeder. The first experiments were carried out with noble gases and they revealed, for example, that the effects of the gas mixing and 2-frequency heating on the production of high charge states appear to be additive for the conventional ECRIS. The results also indicate that at least in the case of noble gases the differences between the conventional ECRIS and the charge breeder cause only minor impact on the production efficiency of ion beams.
RESUMEN
Ion beam intensity and quality have a crucial effect on the operation efficiency of the accelerator facilities. This paper presents the investigations on the ion beam intensity and quality after the mass separation performed with the Department of Physics, University of Jyväskylä 14 GHz electron cyclotron resonance ion source by sweeping the microwave in the 14.05-14.13 GHz range. In many cases a clear variation in the ion beam intensity and quality as a function of the frequency was observed. The effect of frequency tuning increased with the charge state. In addition, clear changes in the beam structure seen with the beam viewer were observed. The results confirmed that frequency tuning can have a remarkable effect on ion beam intensity and quality especially in the case of highly charged ion beams. The examples presented here represent the typical charge state behavior observed during the measurements.
RESUMEN
A general-purpose three-dimensional (3D) simulation code IBSIMU for charged particle optics with space charge is under development at JYFL. The code was originally developed for designing a slit-beam plasma extraction and nanosecond scale chopping for pulsed neutron generator, but has been developed further and has been used for many applications. The code features a nonlinear FDM Poisson's equation solver based on fast stabilized biconjugate gradient method with ILU0 preconditioner for solving electrostatic fields. A generally accepted nonlinear plasma model is used for plasma extraction. Magnetic fields can be imported to the simulations from other programs. The particle trajectories are solved using adaptive Runge-Kutta method. Steady-state and time-dependent problems can be modeled in cylindrical coordinates, two-dimensional (slit) geometry, or full 3D. The code is used via C++ programming language for versatility but it features an interactive easy-to-use postprocessing tool for diagnosing fields and particle trajectories. The open source distribution and public documentation make the code well suited for scientific use. IBSIMU has been used for modeling the 14 GHz ECR ion source extraction and for designing a four-electrode extraction for a 2.45 GHz microwave ion source at Jyväskylä. A grid extraction has also been designed for producing large uniform beam for creating conditions similar to solar wind. The code has also been used to design a H(-) extraction with electron dumping for the Cyclotron Institute of Texas A&M University.
