MOXZO03
FRIB, East Lansing, Michigan, USA
LBNL, Berkeley, California, USA
To satisfy ultimate performance requirements for heavy ions, a 28 GHz superconducting ECR ion source is under development at the Facility for Rare Isotope Beams (FRIB) in collaboration with Berkeley National Laboratory. The construction and testing of the superconducting magnet was completed at Berkeley and delivered to FRIB in January 2018. The magnet and cryostat have been assembled on the high voltage platform. Magnet cooldown and field mapping are planned by the end of 2020. The source commissioning shall start in early 2021. Details of the ion source design, current status of assembly, and commissioning plan will be presented in this paper.
MSU, East Lansing, Michigan, USA
NSCL, East Lansing, Michigan, USA
FRIB, East Lansing, Michigan, USA
Plasma instabilities complicate the operation of electron cyclotron resonance ion sources. In particular, quasi-periodic losses of electrons from confinement due to kinetic cyclotron instabilities hinder ion source performance. Empirical scaling laws help guide the development of sources away from the most unstable operating points but are poorly understood. Further advancement of ECR ion source technologies requires a deeper understanding of instabilities, scaling laws, and internal processes of the ion source plasma itself. We present here results of an experimental study into these instabilities and scaling laws, and measurements of hot electron diffusion (E > 10 keV) from the 18 GHz SUSI ECRIS at the NSCL. Measurements of the average argon current and the standard deviation of their variations across multiple unstable operating points are shown. These measurements are compared to measurements of electrons that diffuse axially from the plasma chamber. In doing so it will be shown how controlling the diffusion of electrons control the stability of the plasma and optimize the ion source’s performance.
MSU, East Lansing, Michigan, USA
FRIB, East Lansing, Michigan, USA
The diffusion of electrons from ECRIS plasmas results in the emission of bremsstrahlung distributions from the plasma chamber. ECRIS bremsstrahlung measurements that are both time- and energy-resolved are often challenging to perform due to the 10’s; 100’s ms timescale that the plasma evolves over. However, the advancement of low-cost microcontrollers over the last decade makes timing and gating photon spectrometers easier. We present a proof of principle measurement which uses an Arduino microcontroller as a gate-and-delay generator for a High Purity Germanium (HPGe) detector. An example plot of the time-resolved bremsstrahlung spectrum, triggered by beam current variation induced by kinetic instabilities, is shown.