Far-Tech, Inc., San Diego, California
ANL, Argonne, Illinois
FAR-TECH, Inc. is developing a non-invasive X-ray spectral diagnostic for monitoring electron cyclotron resonance ion sources (ECRIS). The X-Ray Bremsstrahlung spectrum provides important information about the electron distribution function (EDF), which plays a key role in ionization and production of highly charge ions. To this end, FAR-TECH, Inc. has recently performed extensive measurements of X-ray emission from the ECR-II device in the ATLAS facility at Argonne National Laboratory. Our measurements indicate a significant population of electrons with energies in excess of 100 keV in ECR-II. Furthermore, we find that both the intensity and the shape of the observed spectra are highly correlated with the charge state distribution (CSD) of ions extracted from the ECR-II plasma as measured by a Faraday cup. Measurements of the X-Ray spectra and corresponding CSDs will be presented, as well as analysis of the dependence of the X-ray signal on ECR heating power, working gas pressure, spatial location of the ECR surface, and two-frequency heating. The results will be compared to simulations of ECR-II using our Generalized ECRIS Model (GEM).
Far-Tech, Inc., San Diego, California
The GEM (General ECRIS Model) code is developed by FAR-TECH, Inc. to model plasmas in ECRIS devices using only experimental knobs such as magnetic field, rf and the geometry of the device. The code models ECRIS plasma electrons by the bounce-averaged Fokker-Planck equation, ions as fluid and neutrals by particle balancing. It has been extended to include 2D (axial and radial) spatial features such as 2D ECR heating and ion radial diffusion. The convergence and consistency of the code have been studied. It is parallelized using the MPI technique to boost the calculation speed. Examples of 2D profiles of ECRIS plasmas and the radial dependence of CSD (charge state distribution) will be presented. Also, GEM 2D is merged with the MCBC (Monte Carlo Beam Capture) code to optimize ECR charge breeders. Results of the GEM 2D code and comparisons of GEM 2D and GEM 1D results will be presented.
Far-Tech, Inc., San Diego, California
FAR-TECH has been developing ECR charge breeder optimization toolset. It consists of three computational modules: [1] the GEM (General ECRIS Model) code, [2] the MCBC (Monte Carlo Beam Capture) code, and [3] the IonEx (Ion extraction) code. The GEM code simulates ECR plasmas via Fokker-Plank electrons and ion fluids. MCBC is a particle tracking code to trace the injected charge breeder beam ions, and IonEx simulates the ion extraction region accurately by resolving the plasma sheaths at the extraction region. Current status of the work will be presented along with examples.
[1] J. S. Kim, L. Zhao, B. P. Cluggish, I. N. Bogatu, and R. Pardo, 'Electron cyclotron resonance charge breeder ion source simulation by MCBC', Rev. Sci. Instrum. 79, 02B906 (2008) [2] D. H. Edgell, J. S. Kim, S. K. Wong, R. C. Pardo and R. C. Vondrasek, Rev. Sci. Instrum. 71, 666 (2000) [3] B. P. Cluggish, S. A. Galkin, and J. S. Kim, 'Modeling Ion Extraction from an ECR Ion Source', Proceeding of the 2007 Particle Accelerator Conference, Albuquerque, NM, June 25-29, 2007
