FRIB, East Lansing, USA
JLab, Newport News, Virginia, USA
INFN/LNL, Legnaro (PD), Italy
KEK, Ibaraki, Japan
BNL, Upton, Long Island, New York, USA
ANL, Argonne, Illinois, USA
TRIUMF, Vancouver, Canada
Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 and the National Science Foundation under Cooperative Agreement PHY-1102511.
MSU, East Lansing, Michigan, USA
NSCL, East Lansing, Michigan, USA
FRIB, East Lansing, Michigan, USA
Accelerator facilities for radioactive beams and low energy nuclear physics such as FRIB require intense, stable ion beam currents in order to achieve required reaction rates for rare and undiscovered isotopes. Presently, the only way to produce intense Continuous Wave beams of highly-charged, medium to heavy-mass ions is with Electron Cyclotron Resonance Ion Sources (ECRIS). The complex nature of these devices causes temporal instabilities to occur, most notably: Slow and fast instabilities. Slow instabilities and drifts, occurring over hours, decay the beam current intensity due to variations in ambient and hardware conditions. These drifts require beam operators to constantly monitor and tune ECRIS plasma parameters in order to maintain experimental beam requirements. Fast instabilities, in the form of ms oscillations, occur at operational parameters needed for high-intensity, high-charge state beams. These oscillations cause sudden drops in beam current of the order of 30%. We present here initial results of recent measurements to investigate these instabilities. Results for slow instabilities indicate a linear decay of beam intensity following a sharp current drop due to a brief source conditioning period. Results for fast instabilities show a relationship between the frequency and amplitude of beam oscillations and the electric potential of the plasma chamber bias disk.
NSCL, East Lansing, Michigan, USA
FRIB, East Lansing, USA
MSU, East Lansing, Michigan, USA
Michigan State University, East Lansing, Michigan, USA
Existing heavy ion facilities such as the National Superconducting Cyclotron Laboratory at Michigan State University rely on Electron Cyclotron Resonance (ECR) ion sources as injectors of highly charged ion beams. Long ion confinement times are necessary to produce dense populations of highly charged ions because of steadily decreasing ionization cross sections with increasing charge state. To further understand ion extraction and confinement we are using a fast sputtering technique first developed at Argonne National Laboratory (ANL) [1] to introduce a small amount of uranium metal into the plasma at a well-defined time. We present an analytical solution to the coupled ion density rate equations for using a piecewise constant neutral density to interpret the fast sputtering method.
*R. Vondrasek et al., Rev. Sci. Instrum. 73, 548-551 (2002).
NSCL, East Lansing, Michigan, USA
Heavy ion accelerator laboratories for nuclear science and rare isotope research require a wide array of high intensity heavy ion beams. Due to their versatility and robustness, Electron Cyclotron Resonance (ECR) ion sources are the choice injectors for the majority of these facilities worldwide. Steady improvements in the performance of ECR ion sources have been successful in providing intense primary beams for facilities such as the National Superconducting Cyclotron Laboratory (NSCL). However, next generation heavy ion beam laboratories, such as the Facility for Rare Isotope Beam (FRIB), require intensities that approaching the limits of current possibility with state of the art ion source technology. In this proceedings, we present the ongoing low energy beam transport characterization efforts of a superconducting ECR ion source injector system at the MSU NSCL.