Author: Isherwood, B.C.
Paper Title Page
MOYZO03 The Relationship Between the Diffusion of Hot Electrons, Plasma Stability, and ECR Ion Source Performance 38
 
  • B.C. Isherwood
    MSU, East Lansing, Michigan, USA
  • G. Machicoane
    NSCL, East Lansing, Michigan, USA
  • G. Machicoane
    FRIB, East Lansing, Michigan, USA
  
  Funding: This research was made possible by the National Science Foundation under NSF Grant 1632761 and the U.S. Department of Energy Award Number DE-SC0018362.
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. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ECRIS2020-MOYZO03  
About • Received ※ 30 September 2020 — Revised ※ 20 October 2020 — Accepted ※ 19 January 2021 — Issue date ※ 11 April 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOZZO06 Microcontrollers as Gate and Delay Generators for Time Resolved Measurements 57
 
  • B.C. Isherwood
    MSU, East Lansing, Michigan, USA
  • G. Machicoane
    FRIB, East Lansing, Michigan, USA
  
  Funding: This research was made possible by the National Science Foundation under NSF Grant 1632761 and the U.S. Department of Energy Award Number DE-SC0018362.
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. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ECRIS2020-MOZZO06  
About • Received ※ 30 September 2020 — Revised ※ 21 October 2020 — Accepted ※ 19 January 2021 — Issue date ※ 23 December 2021
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)