Lau, Yuk Yeung = 重離子核聚變驅動設備的最終壓縮離子束線系統 / 劉鈺暘. / "November 2011." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (p. 99-101). / Abstracts in English and Chinese. / Lau, Yuk Yeung = Zhong li zi he ju bian qu dong she bei de zui zhong ya suo li zi shu xian xi tong / Liu Yuyang. / Abstract --- p.i / 概要 --- p.iii / Acknowledgements --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background --- p.5 / Chapter 2.1 --- Nuclear fusion --- p.5 / Chapter 2.1.1 --- Nuclear fusion as an energy source --- p.5 / Chapter 2.1.2 --- Lawson criterion --- p.7 / Chapter 2.1.3 --- Confinement method --- p.8 / Chapter 2.2 --- Inertial confinement fusion --- p.11 / Chapter 2.2.1 --- Driving beams --- p.11 / Chapter 2.2.2 --- Reactor chamber --- p.14 / Chapter 2.2.3 --- Ignition target --- p.14 / Chapter 2.3 --- Heavy ion inertial confinement fusion --- p.16 / Chapter 2.3.1 --- Beam source and accelerator system --- p.18 / Chapter 2.3.2 --- Drift compression section --- p.20 / Chapter 2.4 --- Beam dynamics --- p.23 / Chapter 2.4.1 --- Transverse dynamics --- p.24 / Chapter 2.4.2 --- Longitudinal dynamics --- p.26 / Chapter 2.4.3 --- Emittance --- p.27 / Chapter 2.5 --- Simulation codes --- p.28 / Chapter 2.5.1 --- Particle in cell simulation --- p.28 / Chapter 2.5.2 --- WARP code --- p.29 / Chapter 3 --- Drift compression beamline system for heavy ion fusion drivers --- p.31 / Chapter 3.1 --- Beam requirements for target implosion in HIF driver --- p.31 / Chapter 3.2 --- Drift compression beamline configuration --- p.33 / Chapter 3.3 --- Simulation example --- p.39 / Chapter 3.4 --- Minimization of centroid offset with bend strategies --- p.42 / Chapter 3.5 --- Neutralized drift section and final focusing --- p.50 / Chapter 3.6 --- "Final pulse length, spot size and emittance" --- p.52 / Chapter 4 --- Longitudinal emittance growth due to non-linear space charge effects --- p.61 / Chapter 4.1 --- Longitudinal emittance growth in the linear regime - Simulation results --- p.62 / Chapter 4.2 --- Longitudinal emittance growth in the linear regime - analytical results --- p.67 / Chapter 4.2.1 --- Beam with uniform radius --- p.68 / Chapter 4.2.2 --- Beam with uniform density --- p.73 / Chapter 4.2.3 --- Comparison with simulations --- p.76 / Chapter 4.2.4 --- Extension to more general beams --- p.78 / Chapter 4.3 --- Longitudinal emittance evolution in the nonlinear regime --- p.79 / Chapter 4.4 --- Target pulse length minimization --- p.86 / Chapter 4.4.1 --- Optimization of drift compression beamline and beam parameters --- p.86 / Chapter 4.4.2 --- Phase space correction with initial voltage waveform tailoring --- p.90 / Chapter 4.5 --- Coupling of Longitudinal and Transverse Emittances --- p.91 / Chapter 5 --- Summary --- p.95 / Bibliography --- p.99

Ling, Chi Yeung = 作高能量密度物理研究的一種新型強離子束加速器的模擬 / 凌子陽. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (p. 111-114). / Abstracts in English and Chinese. / Ling, Chi Yeung = Zuo gao neng liang mi du wu li yan jiu de yi zhong xin xing qiang li zi shu jia su qi de mo ni / Ling Ziyang. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background --- p.7 / Chapter 2.1 --- High Energy Density Physics and Warm Dense Matter --- p.7 / Chapter 2.1.1 --- Definition of HEDP and WDM --- p.7 / Chapter 2.1.2 --- The physics of WDM --- p.9 / Chapter 2.1.3 --- Advantages of the ion beam approach --- p.10 / Chapter 2.2 --- Intense low energy ion beam machines requirements for NDCX-II --- p.12 / Chapter 2.3 --- Neutralized Drift Compression Experiment (NDCX) --- p.14 / Chapter 2.3.1 --- Neutralized Transport Experiment (NTX) --- p.15 / Chapter 2.3.2 --- The first NDCX --- p.18 / Chapter 2.4 --- Accelerator architectures proposed for NDCX-II --- p.20 / Chapter 2.4.1 --- Radio Frequency Linear Accelerator (RF Linac) --- p.20 / Chapter 2.4.2 --- Electrostatic accelerator --- p.23 / Chapter 2.4.3 --- Drift Tube Linac (DTL) --- p.23 / Chapter 2.4.4 --- Linear Induction Accelerator (induction linac) --- p.24 / Chapter 2.5 --- Pulse Line Ion Accelerator --- p.25 / Chapter 2.6 --- Review on tests of Pulse Line Ion Accelerator --- p.30 / Chapter 2.7 --- Simulation codes --- p.32 / Chapter 2.7.1 --- 3-D Electromagnetic code MAFIA --- p.33 / Chapter 2.7.2 --- Particle-in-cell code WARP --- p.35 / Chapter 2.8 --- Envelope equation of ion beam and beam diagnostics --- p.37 / Chapter 3 --- Investigations on insulator breakdown in the PLIA --- p.40 / Chapter 3.1 --- Modeling in MAFIA --- p.40 / Chapter 3.2 --- Scaling Law --- p.42 / Chapter 3.3 --- Investigation of different frequency modes near insulator surface --- p.46 / Chapter 3.4 --- Standing wave effect in PLIA --- p.50 / Chapter 3.5 --- Conclusion --- p.52 / Chapter 4 --- PLIA based design for the second Neutralized Drift Compression Experiment --- p.55 / Chapter 4.1 --- The injector --- p.56 / Chapter 4.2 --- Pulse Line Ion Accelerator sections --- p.60 / Chapter 4.2.1 --- Basic design strategy --- p.60 / Chapter 4.2.2 --- Simulation results of PLIA sections --- p.69 / Chapter 4.3 --- Neutralized Drift Compression Section --- p.77 / Chapter 4.3.1 --- Drift length --- p.78 / Chapter 4.3.2 --- First focusing solenoid --- p.80 / Chapter 4.3.3 --- Plasma-filled region --- p.84 / Chapter 4.3.4 --- Final focusing solenoid and the best focal point --- p.88 / Chapter 4.3.5 --- Sensitivity to drift length and focusing strength --- p.91 / Chapter 4.4 --- Conclusion --- p.92 / Chapter 5 --- Other Pulse Power Options --- p.94 / Chapter 5.1 --- The injector and the beamline --- p.95 / Chapter 5.2 --- 3-meter electrostatic column --- p.97 / Chapter 5.3 --- Induction linac --- p.100 / Chapter 5.4 --- Hybrid of induction linac and Pulse Line Ion Accelerator --- p.104 / Chapter 5.5 --- Conclusion --- p.107 / Chapter 6 --- Discussions --- p.108 / Chapter 6.0.1 --- Future development of PLIA --- p.110 / Bibliography --- p.111

Accelerator mass spectrometry (AMS) has been used routinely for radiocarbon measurements for several years. During this period it has become evident neither the accuracy nor the range of the technique were as great as had originally been hoped. This thesis describes both theoretical work to understand the reasons for this and practical solutions to overcome some of the problems. The production and transport of the ions used in the measurements are found to be the most crucial stages in the process. The theories behind ion production by sputtering are discussed and applied to the specific case of carbon sputtered by caesium. Experimental evidence is also examined in relation to the theories. The phenomena of space charge and lens aberrations are discussed along with the interaction between ion beams and gas molecules in the vacuum. Computer programs for calculating phase space transformations are then described; these are designed to help investigations of the effects of space charge and aberrations on AMS measurements. Calculations using these programs are discussed in relation both to measured ion beam profiles in phase space and to the current dependent transmission of ions through the Oxford radiocarbon accelerator. Improvements have been made to this accelerator and these are discussed in the context of the calculations. There are many reasons for wishing to produce C^- ions directly from carbon dioxide. The most suitable type of source for achieving this is the Middleton High Intensity Sputter Source. Experiments to evaluate the performance of such a source are described and detailed design criteria established. An ion source designed and built specifically for radiocarbon measurements using carbon dioxide is described. Experiments to evaluate its performance and investigate the underlying physical processes are discussed. The source is found to have a high efficiency enabling small samples (<100 μg of carbon) to be measured. The cross contamination is measured to be low (<0.1%) and the background currents are small; the implications of these results are discussed.

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xiv, 173 p. : ill. (some col). Vita. Includes abstract. Includes bibliographical references.

A Moak type radio frequency ion source, capable of producing a pulsed beam of deuterons has been built for use with a Cockcroft-Walton accelerator. Pulsed deuterons striking a deuteron target produce neutrons in bursts thus allowing dynamic measurements of moderator and reactor core properties. Beam pulsing is accomplished by means of an einzel lens and an alternating potential applied to a pair of deflection plates. Proteins have been used exclusively in adjusting the source for optimum results since the radiation background due to the protons is much less than that due to deuterons. In actual experiments, however, when using deuterons, no modifications need to be made in the source. Beam currents have been measured at the source and at a target located at the end of the accelerator tube. Maximum currents measured are 150 microamperes and 60 microamperes respectively. Details of construction, maximum operating conditions, and oscillogram sof purse shapes are included in this report. / M.S.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Beams of polarized protons play an important part in the study of the spin dependence of the nuclear force by measuring the analyzing power in nuclear reactions. The source at iThemba LABS produces a beam of polarized protons that is pre-accelerated by an injector cyclotron (SPC2) to a energy of 8 MeV before acceleration by the main separated-sector cyclotron to 200 MeV for physics research. The polarized ion source is one of the two external ion sources of SPC2. Inside the ion source hydrogen molecules are dissociated into atoms in the dissociator and cooled to a temperature of approximately 30 K in the nozzle. The atoms are polarized by a pair of sextupole magnets and the nucleus is polarized by RF transitions between hyperfine levels in hydrogen atoms. The atoms are then ionized by electrons in the ionizer. The source has various sensitive devices, which influence beam intensity and polarization. Nitrogen gas is used to prevent recombination of atoms after dissociation. The amount of nitrogen and the temperature at which it is used plays a very important role in optimizing the beam current. The number of electrons released in the ionizer is influenced by the size and shape of the filament. Optimization of the source will ensure that beams of better quality (a better current and stability) are produced.

Beams of polarized protons play an important part in the study of the spin dependence of the nuclear force by measuring the analyzing power in nuclear reactions. The source at iThemba LABS produces a beam of polarized protons that is pre-accelerated by an injector cyclotron (SPC2) to a energy of 8 MeV before acceleration by the main separated-sector cyclotron to 200 MeV for physics research. The polarized ion source is one of the two external ion sources of SPC2. Inside the ion source hydrogen molecules are dissociated into atoms in the dissociator and cooled to a temperature of approximately 30 K in the nozzle. The atoms are polarized by a pair of sextupole magnets and the nucleus is polarized by RF transitions between hyperfine levels in hydrogen atoms. The atoms are then ionized by electrons in the ionizer. The source has various sensitive devices, which influence beam intensity and polarization. Nitrogen gas is used to prevent recombination of atoms after dissociation. The amount of nitrogen and the temperature at which it is used plays a very important role in optimizing the beam current. The number of electrons released in the ionizer is influenced by the size and shape of the filament. Optimization of the source will ensure that beams of better quality (a better current and stability) are produced.

Magister Scientiae - MSc / Beams of polarized protons play an important part in the study of the spin dependence of the nuclear force by measuring the analyzing power in nuclear reactions. The source at iThemba LABS produces a beam of polarized protons that is pre-accelerated by an injector cyclotron (SPC2) to a energy of 8 MeV before acceleration by the main separated-sector cyclotron to 200 MeV for physics research. The polarized ion source is one of the two external ion sources of SPC2. Inside the ion source hydrogen molecules are dissociated into atoms in the dissociator and cooled to a temperature of approximately 30 K in the nozzle. The atoms are polarized by a pair of sextupole magnets and the nucleus is polarized by RF transitions between hyperfine levels in hydrogen atoms. The atoms are then ionized by electrons in the ionizer. The source has various sensitive devices, which influence beam intensity and polarization. Nitrogen gas is used to prevent recombination of atoms after dissociation. The amount of nitrogen and the temperature at which it is used plays a very important role in optimizing the beam current. The number of electrons released in the ionizer is influenced by the size and shape of the filament. Optimization of the source will ensure that beams of better quality (a better current and stability) are produced. / South Africa

A helicon plasma source is a device that can efficiently ionize a gas to create high density, low temperature plasma. There is growing interest in utilizing a helicon plasma source in propulsive applications, but it is not yet known if the helicon plasma source is able to function as both an ion source and ion accelerator, or whether an additional ion acceleration stage is required. In order to evaluate the capability of the helicon source to accelerate ions, the acceleration and ionization processes must be decoupled and examined individually. To accomplish this, a case study of two helicon thruster configurations is conducted. The first is an electrodeless design that consists of the helicon plasma source alone, and the second is a helicon ion engine that combines the helicon plasma source with electrostatic grids used in ion engines. The gridded configuration separates the ionization and ion acceleration mechanisms and allows for individual evaluation not only of ion acceleration, but also of the components of total power expenditure and the ion production cost. In this study, both thruster configurations are fabricated and experimentally characterized. The metrics used to evaluate ion acceleration are ion energy, ion beam current, and the plume divergence half-angle, as these capture the magnitude of ion acceleration and the bulk trajectory of the accelerated ions. The electrode-less thruster is further studied by measuring the plasma potential, ion number density, and electron temperature inside the discharge chamber and in the plume up to 60 cm downstream and 45 cm radially outward. The two configurations are tested across several operating parameter ranges: 343-600 W RF power, 50-450 G magnetic field strength, 1.0-4.5 mg/s argon flow rate, and the gridded configuration is tested over a 100-600 V discharge voltage range. Both configurations have thrust and efficiency below that of contemporary thrusters of similar power, but are distinct in terms of ion acceleration capability. The gridded configuration produces a 65-120 mA ion beam with energies in the hundreds of volts that is relatively collimated. The operating conditions also demonstrate clear control over the performance metrics. In contrast, the electrodeless configuration generally produces a beam current less than 20 mA at energies between 20-40 V in a very divergent plume. The ion energy is set by the change in plasma potential from inside the device to the plume. The divergence ion trajectories are caused by regions of high plasma potential that create radial electric fields.. Furthermore, the operating conditions have limited control of the resulting performance metrics. The estimated ion production cost of the helicon ranged between 132-212 eV/ion for argon, the lower bound of which is comparable to the 157 eV/ion in contemporary DC discharges. The primary power expenditures are due to ion loss to the walls and high electron temperature leading to energy loss at the plasma sheaths. The conclusion from this work is that the helicon plasma source is unsuitable as a single-stage thruster system. However, it is an efficient ion source and, if paired with an additional ion acceleration stage, can be integrated into an effective propulsion system.