A new microwave electron cyclotron resonance (ECR) multicusp plasma ion source using two ECR plasma production regions and multicusp plasma confinement has been developed at Oak Ridge National Laboratory. This source has been operated to produce uniform and dense plasmas over large areas of 300 to 400 cm2. The plasma source has been operated with continuous argon gas feed and pulsed microwave power. The discharge initiation phenomena and plasma properties have been investigated and studied as functions of discharge parameters. Together with the discharge characteristics observed, a hypothetical discharge mechanism for this plasma source is reported and discussed. Potential applications, including plasma and ion-beam processing for manufacturing advanced microelectronics and for space electric propulsion, are discussed. 7 refs., 6 figs.
A new microwave electron cyclotron resonance (ECR) multicusp plasma ion source that has two ECR plasma production regions and uses multicusp plasma confinement has been developed at Oak Ridge National Laboratory. This source has been operated to produce uniform and dense plasma over large areas of 300 to 400 cm2 and could be scaled up to produce uniform plasma over 700 cm2 or larger. The plasma source has been operated with continuous argon gas feed and pulsed microwave power. The working gases used were argon, helium, hydrogen, and oxygen. The discharge initiation phenomena and plasma properties have been investigated and studied as functions of the discharge parameters. The discharge characteristics and a hypothetical discharge mechanism for this plasma source are described and discussed. Potential applications, including plasma and ion-beam sources for manufacturing advanced microelectronics, for space electric propulsion, and for fusion research, are discussed. 10 refs., 10 figs.
Acknowledged as the "founding father" of and world renowned expert on electron cyclotron resonance sources Richard Geller has produced a unique book devoted to the physics and technicalities of electron cyclotron resonance sources. Electron Cyclotron Resonance Ion Sources and ECR Plasmas provides a primer on electron cyclotron phenomena in ion sour
This report contains papers on the following topics: Recent Developments and Future Projects on ECR Ion Sources; Operation of the New KVI ECR Ion Source at 10 GHz; Operational Experience and Status of the INS SF-ECR Ion Source; Results of the New ECR4'' 14.5 GHz ECRIS; Preliminary Performance of the AECR; Experimental Study of the Parallel and Perpendicular Particle Losses from an ECRIS Plasma; Plasma Instability in Electron Cyclotron Resonance Heated Ion Sources; The Hyperbolic Energy Analyzer; Status of ECR Source Development; The New 10 GHz CAPRICE Source; First Operation of the Texas A M ECR Ion Source; Recent Developments of the RIKEN ECR Ion Sources; The 14 GHz CAPRICE Source; Characteristics and Potential Applications of an ORNL Microwave ECR Multicusp Plasma Ion Source; ECRIPAC: The Production and Acceleration of Multiply Charged Ions Using an ECR Plasma; ECR Source for the HHIRF Tandem Accelerator; Feasibility Studies for an ECR-Generated Plasma Stripper; Production of Ion Beams by using the ECR Plasmas Cathode; A Single Stage ECR Source for Efficient Production of Radioactive Ion Beams; The Single Staged ECR Source at the TRIUMF Isotope Separator TISOL; The Continuous Wave, Optically Pumped H− Source; The H ECR Source for the LAMPF Optically Pumped Polarized Ion Source; Present Status of the Warsaw CUSP ECR Ion Source; An ECR Source for Negative Ion Production; GYRAC-D: A Device for a 200 keV ECR Plasma Production and Accumulation; Status Report of the 14.4 GHZ ECR in Legnaro; Status of JYFL-ECRIS; Report on the Uppsala ECRIS Facility and Its Planned Use for Atomic Physics; A 10 GHz ECR Ion Source for Ion-Electron and Ion-Atom Collision Studies; and Status of the ORNL ECR Source Facility for Multicharged Ion Collision Research.
Recent research has brought the application of microwaves from the classical fields of heating, communication, and generation of plasma discharges into the generation of compact plasmas that can be used for applications such as FIB and small plasma thrusters. However, these new applications bring with them a new set of challenges. With coverage ranging from the basics to new and emerging applications, Compact Plasma and Focused Ion Beams discusses how compact high-density microwave plasmas with dimensions smaller than the geometrical cutoff dimension can be generated and utilized for providing focused ion beams of various elements. Starting with the fundamentals of the cutoff problem for wave propagation in waveguides and plasma diagnostics, the author goes on to explain in detail the plasma production by microwaves in a compact geometry and narrow tubes. He then thoroughly discusses wave interaction with bounded plasmas and provides a deeper understanding of the physics. The book concludes with an up-to-date account of recent research on pulsed microwaves and the application of compact microwave plasmas for multi-element FIB. It provides a consolidated and unified description of the emerging areas in plasma science and technology utilizing wave-based plasma sources based on the author’s own work and experience. The book will be useful not only to established researchers in this area but will also serve as an excellent introduction to those interested in applying these ideas to various current and new applications.
Heavy ion accelerators are a valuable resource for the nuclear science community to study atomic physics. One such heavy ion accelerator is the Coupled Cyclotron Facility (CCF) at the National Superconducting Cyclotron Laboratory (NSCL) which relies on Electron Cyclotron Resonance (ECR) ion sources to provide the primary beam to the target. ECR ion sources are essential for the efficient operation of research accelerators such as the CCF, providing high currents of highly charged ions. Highly charged ion beams increase the efficiency of the accelerators, but require longer confinement times and higher temperature plasmas in the ion sources than is necessary to produce singly charged beams. The need to use high temperature and low density plasmas creates challenges including those relating to plasma stability. ECR ion sources provide a good platform to accept metallic vapor ovens and sputtering probes allowing the CCF to accelerate up to 30 types of beams ranging from oxygen to uranium. Furthermore, ECR ion sources use no filaments or cathodes providing a high degree of reliability for the accelerator facility. As the intensity frontier demands ever rarer isotopes from accelerator facilities, the heavy ion beam intensity must increase [70], which creates new demands from the ion sources.The work presented within this dissertation set out to better understand the mechanism that confines highly charged ions in the ECR plasma. Specifically, it was explored if hot electrons (energy larger than 50 keV) contribute to ion confinement by generating an electrostatic well in the plasma potential [68]. Perturbative measurements of ECR ion sources are presented with the aim to explore ion confinement times: pulsed sputtering (Chapter 4) and amplitude modulation (Chapter 5). Chapter 3 explores the geometry of the sputtering probe with respect to the magnetic field which was crucial to produce reliable pulsed sputtering results on the ECR ion source. Axial pulsed sputtering, which could be conveniently implemented on fully superconducting sources, incorporated a bias disc effect that highly perturbed the plasma. Radial sputtering was emulated by placing a semi-shielded probe along the plasma chamber wall in between the electron loss surfaces.Ion confinement time was characterized through the decay time of the beam current, which is proportional to ion confinement time. Ion beam decay times were measured for different charge states of gold in an oxygen plasma in Chapter 4. Decay time always increased with increasing charge state. Decay time also increased with hot electron temperature for lower frequency operation (13 GHz), but reached an optimized value for higher frequency operation (18 GHz) due to plasma instabilities. Electrostatic confinement of ions appeared to be the most plausible mechanism to explain the observed decay time behaviors. A novel perturbative measurement technique was developed for ECR ion sources using Amplitude Modulation (AM) of microwave power. The AM measurement was originally motivated by whether or not 50~kHz modulation in microwave power (from the microwave source) would be observable in the beam current. A systematic study was organized on the University of Jyvaskyla Physics Department (JYFL) normal conducting ECR ion source in Jyvaskyla Finland. Chapter 5 presents the beam current response to AM on the 14 GHz ECR ion source for different weights of noble gases, magnetic fields, and vacuum pressures. The beam current amplitude generally decayed exponentially for frequencies higher than around 400 Hz with the modulation highly suppressed at 10 kHz.
