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Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy, and Related Fields

Description: Some years ago it was suggested that halogen negative ions [1]could offer a feasible alternative path to positive ions as a heavy ion fusion driver beam which would not suffer degradation due to electron accumulation in the accelerator and beam transport system, and which could be converted to a neutral beam by photodetachment near the chamber entrance if desired. Since then, experiments have demonstrated that negative halogen beams can be extracted and accelerated away from the gas plume near the source with a surviving current density close to what could be achieved with a positive ion of similar mass, and with comparable optical quality. In demonstrating the feasibility of halogen negative ions as heavy ion driver beams, ion - ion plasmas, an interesting and somewhat novel state of matter, were produced. These plasmas, produced near the extractor plane of the sources, appear, based upon many lines of experimental evidence, to consist of almost equal densities of positive and negative chlorine ions, with only a small component of free electrons. Serendipitously, the need to extract beams from this plasma for driver development provides a unique diagnostic tool to investigate the plasma, since each component - positive ions, negative ions, and electrons -- can be extracted and measured separately. We discuss the relevance of these observations to understanding negative ion beam extraction from electronegative plasmas such as halogens, or the more familiar hydrogen of magnetic fusion ion sources. We suggest a concept which might improve negative hydrogen extraction by the addition of a halogen. The possibility and challenges of producing ion-ion plasmas with thin targets of halogens or, perhaps, salt, is briefly addressed.
Date: August 1, 2008
Creator: Grisham, L.R. & Kwan, J.W.
Partner: UNT Libraries Government Documents Department

Source fabrication and lifetime for Li{sup +} ion beams extracted from alumino-silicate sources

Description: A space-charge-limited beam with current densities (J) exceeding 1 mA/cm{sup 2} have been measured from lithium alumino-silicate ion sources at a temperature of ∼1275{degrees}C. At higher extraction voltages, the source appears to become emission limited with J ≥ 1.5 mA/cm{sup 2}, and J increases weakly with the applied voltage. A source with an alumino-silicate coating 6.35 mm in diameter and ≤0.25 mm thick, has a lifetime of ∼40 hours at ∼1275{degrees}C, when pulsed at 0.05 Hz and with pulse length of ∼6 μs each. At this rate, the source lifetime was independent of the actual beam charge extracted due to the loss of neutral atoms at high temperature. Furthermore, the source lifetime increases with the amount of alumino-silicate coated on the emitting surface, and may also be extended if the temperature is reduced between pulses.
Date: February 10, 2012
Creator: Greenway, W. G. & Kwan, J. W.
Partner: UNT Libraries Government Documents Department

Compact High-Current Heavy-Ion Injector

Description: To provide a compact high-brightness heavy-ion beam source for Heavy Ion Fusion (HIF), we have been experimenting with merging multi-beamlets in an injector which uses an RF plasma source. An array of converging beamlets was use to produce a beam with the envelope radius, convergence, and ellipticity matched to an electrostatic quadrupole (ESQ) channel. Experimental results were in good quantitative agreement with simulation and have demonstrated the feasibility of this concept. The size of a driver-scale injector system using this approach will be several times smaller than one designed using traditional single large-aperture beams. The success of this experiment has possible significant economical and technical impacts on the architecture of HIF drivers.
Date: April 13, 2006
Creator: Westenskow, G A; Grote, D P; Kwan, J W & Bieniosek, F
Partner: UNT Libraries Government Documents Department

Fast Pulsing Neutron Generators for Security Application

Description: Active neutron interrogation has been demonstrated to be an effective method of detecting shielded fissile material. A fast fall-time/fast pulsing neutron generator is needed primarily for differential die-away technique (DDA) interrogation systems. A compact neutron generator, currently being developed in Lawrence Berkeley National Laboratory, employs an array of 0.6-mm-dia apertures (instead of one 6-mm-dia aperture) such that gating the beamlets can be done with low voltage and a small gap to achieve sub-microsecond ion beam fall time and low background neutrons. Arrays of 16 apertures (4x4) and 100 apertures (10x10) have been designed and fabricated for a beam extraction experiment. The preliminary results showed that, using a gating voltage of 1200 V and a gap distance of 1 mm, the fall time of extracted ion beam pulses is approximately 0.15 mu s at beam energies of 1000 eV.
Date: April 24, 2009
Creator: Ji, Q.; Regis, M. & Kwan, J. W.
Partner: UNT Libraries Government Documents Department

Status of the Neutralized Drift Compression Experiment (NDCX-II)

Description: The Neutralized Drift Compression Experiment (NDCX-II) is an 11 M$ induction accelerator project currently in construction at Lawrence Berkeley National Laboratory for warm dense matter (WDM) experiments investigating the interaction of ion beams with matter at elevated temperature and pressure. The machine consists of a lithium injector, induction accelerator cells, diagnostic cells, a neutralized drift compression line, a final focus solenoid, and a target chamber. The induction cells and some of the pulsed power systems have been reused from the decommissioned Advanced Test Accelerator at Lawrence Livermore National Laboratory after refurbishment and modification. The machine relies on a sequence of acceleration waveforms to longitudinally compress the initial ion pulse from 600 ns to less than 1 ns in {approx} 12 m. Radial confinement of the beam is achieved with 2.5 T pulsed solenoids. In the initial hardware configuration, 50 nC of Li{sup +} will be accelerated to 1.25 MeV and allowed to drift-compress to a peak current of {approx}40 A. The project started in the summer of 2009. Construction of the accelerator will be completed in the fall of 2011 and will provide a worldwide unique opportunity for ion-driven warm dense matter experiments as well as research related to novel beam manipulations for heavy ion fusion drivers.
Date: April 21, 2011
Creator: Waldron, W. L. & Kwan, J. W.
Partner: UNT Libraries Government Documents Department

Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy,and Related Fields

Description: Some years ago it was suggested that halogen negative ions could offer a feasible alternative path to positive ions as a heavy ion fusion driver beam which would not suffer degradation due to electron accumulation in the accelerator and beam transport system, and which could be converted to a neutral beam by photodetachment near the chamber entrance if desired. Since then, experiments have demonstrated that negative halogen beams can be extracted and accelerated away from the gas plume near the source with a surviving current density close to what could be achieved with a positive ion of similar mass, and with comparable optical quality. In demonstrating the feasibility of halogen negative ions as heavy ion driver beams, ion - ion plasmas, an interesting and somewhat novel state of matter, were produced. These plasmas, produced near the extractor plane of the sources, appear, based upon many lines of experimental evidence, to consist of almost equal densities of positive and negative chlorine ions, with only a small component of free electrons. Serendipitously, the need to extract beams from this plasma for driver development provides a unique diagnostic tool to investigate the plasma, since each component - positive ions, negative ions, and electrons - can be extracted and measured separately. We discuss the relevance of these observations to understanding negative ion beam extraction from electronegative plasmas such as halogens, or the more familiar hydrogen of magnetic fusion ion sources. We suggest a concept which might improve negative hydrogen extraction by the addition of a halogen. The possibility and challenges of producing ion - ion plasmas with thin targets of halogens or, perhaps, salt, is briefly addressed.
Date: August 1, 2008
Creator: Grisham, L. R. & Kwan, J. W.
Partner: UNT Libraries Government Documents Department

Development of the 2-MV injector for HIF

Description: The 2-MV Injector consists of a 17-cm-diameter surface ionization source, an extraction diode, and an electrostatic quadrupole (ESQ) accelerator, with maximum current of 0.8 A of potassium beam at 2 MeV. Previous performance of the Injector produced a beam with adequate current and emittance but with a hollow profile at the end of the ESQ section. We have examined the profile of the beam as it leaves the diode. The measured nonuniform beam density distribution qualitatively agrees with EGUN simulation. Implications for emittance growth in the post acceleration and transport phase will be investigated.
Date: March 17, 2000
Creator: Bieniosek, F.M.; Kwan, J.W.; Henestroza, E. & Kim, C.
Partner: UNT Libraries Government Documents Department

Arc-Discharge Ion Sources for Heavy Ion Fusion

Description: A miniature multiple beamlet approach to an injector system was recently proposed in order to reduce the size, cost, and power requirements of the injector. The beamlets of very high current density are needed to meet the brightness requirement. Besides vacuum arc ion sources, cold-cathode gas ion sources are candidates for this application. Vacuum-arc metal ion sources and vacuum-arc-like gas ion sources are discussed. Experiments are presented that focus on the short-pulse plasma composition and ion charge state distribution. Mg and Sr have been identified as the most promising metals leading to mono-species beams when 20 {mu}s arc pulses are used. It is shown that the efficient production of gas ions requires the presence of a magnetic field.
Date: March 1, 2000
Creator: Anders, A. & Kwan, J.W.
Partner: UNT Libraries Government Documents Department

High current density beamlets from RF Argon source for heavy ion fusion applications

Description: In a new approach to develop high current beams for heavy ion fusion, beam current at about 0.5 ampere per channel can be obtained by merging an array of high current density beamlets of 5 mA each. We have done computer simulations to study the transport of high current density beamlets and the emittance growth due to this merging process. In our RF multicusp source experiment, we have produced a cluster of 61 beamlets using minimum gas flow. The current density from a 0.25 cm diameter aperture reached 100 mA/cm{sup 2}. The normalized emittance of 0.02 {pi}-mm-mrad corresponds to an equivalent ion temperature of 2.4 eV. These results showed that the RF argon plasma source is suitable for producing high current density beamlets that can be merged to form a high current high brightness beam for HIF application.
Date: August 1, 2003
Creator: Kwan, J.W.; Grote, D.P. & Westenskow, G.
Partner: UNT Libraries Government Documents Department

Measured and calculated pressure in the transverse field focusing (TFF) matching/pumping section of a negative ion beamline

Description: A negative ion based neutral beam injection system is under development as proof-of-principle demonstration of a radiation-hardened beamline. The beamline consists of a source, a pre-accelerator, a matching/pumping (M/P) section, and an accelerator. The design of the M/P section was done with the aid of a two dimensional Monte Carlo computer code which was used to calculate the pressure along the beam path. The calculated and measured pressures are presented for several locations in the M/P section. 4 refs., 4 figs., (LEW)
Date: November 1, 1985
Creator: Purgalis, P.; Ackerman, G.; Kwan, J.W.; Paterson, J.A. & Wandesforde, A.H.
Partner: UNT Libraries Government Documents Department

Injector for RFQ using electrostatically focused transport and matching

Description: We discuss the principles and performance of a new type of high- current H{sup -} injector for RFQs. The distinguishing feature of our injector is that we replace the conventional gas-neutralized transport and matching units by electrostatic focusing units. Our system prevents plasma formation along the beam instead of utilizing it. Some advantages of this approach are discussed. 13 refs., 6 figs.
Date: November 1, 1989
Creator: Anderson, O.A.; Soroka, L.; Kwan, J.W. & Wells, R.P.
Partner: UNT Libraries Government Documents Department

Experimental evaluation of a negative ion source for a heavy ionfusion negative ion driver

Description: Negative halogen ions have recently been proposed as a possible alternative to positive ions for heavy ion fusion drivers because electron accumulation would not be a problem in the accelerator, and if desired, the beams could be photodetached to neutrals [1,2,3]. To test the ability to make suitable quality beams, an experiment was conducted at Lawrence Berkeley National Laboratory using chlorine in an RF-driven ion source. Without introducing any cesium (which is required to enhance negative ion production in hydrogen ion sources) a negative chlorine current density of 45 mA/cm{sup 2} was obtained under the same conditions that gave 57 mA/cm{sup 2} of positive chlorine, suggesting the presence of nearly as many negative ions as positive ions in the plasma near the extraction plane. The negative ion spectrum was 99.5% atomic chlorine ions, with only 0.5% molecular chlorine, and essentially no impurities. Although this experiment did not incorporate the type of electron suppression technology that is used in negative hydrogen beam extraction, the ratio of co-extracted electrons to Cl{sup -} was as low as 7 to 1, many times lower than the ratio of their mobilities, suggesting that few electrons are present in the near-extractor plasma. This, along with the near-equivalence of the positive and negative ion currents, suggests that the plasma in this region was mostly an ion-ion plasma. The negative chlorine current density was relatively insensitive to pressure, and scaled linearly with RF power. If this linear scaling continues to hold at higher RF powers, it should permit current densities of 100 mA/cm{sup 2}, sufficient for present heavy ion fusion injector concepts. The effective ion temperatures of the positive and negative ions appeared to be similar and relatively low for a plasma source.
Date: January 18, 2005
Creator: Grisham, L. R.; Hahto, S. K.; Hahto, S. T.; Kwan, J. W. & Leung, K. N.
Partner: UNT Libraries Government Documents Department

Fabrication of large diameter alumino-silicate K{sup +} sources

Description: Alumino-silicate K{sup +} sources have been used in HIF experiments for many years. For example the Neutralized Transport Expt. (NTX) and the High Current Transport Expt. (HCX) are now using this type of ion source with diameters of 2.54 cm and 10 cm respectively. These sources have demonstrated ion currents of 80 mA and 700 mA, for typical HIF pulse lengths of 5-10 {micro}s. The corresponding current density is {approx} 10-15 mA/cm{sup 2}, but much higher current density has been observed using smaller size sources. Recently we have improved our fabrication techniques and, therefore, are able to reliably produce large diameter ion sources with high quality emitter surface without defects. This note provides a detailed description of the procedures employed in the fabrication process. The variables in the processing steps affecting surface quality, such as substrate porosity, powder size distribution, coating technique on large area concave surfaces, drying, and heat firing temperature have been investigated.
Date: February 20, 2003
Creator: Baca, D.; Chacon-Golcher, E.; Kwan, J.W. & Wu, J.K.
Partner: UNT Libraries Government Documents Department

Diffusion of alkali species in porous tungsten substrates used in contact-ionization sources

Description: Contact ionization (doped) sources used in current Heavy Ion Fusion (HIF) experiments consist of a porous tungsten substrate doped with an alkali carbonate. During the early stages of the heating cycle (T {approx} 600 C), the carbonate breaks down and releases the alkali atoms that then diffuse through the substrate. At the emitter surface there is a balance between the fast desorption rate of the alkali atoms (mostly as neutrals) and the slower replenishment rate from the substrate by diffusion. Time-resolved measurements of neutral particle evaporation rates at the emitter surface have been used to estimate the effective diffusion coefficient (D) that characterizes the migration of alkali species in the substrate. These estimates are consistent with the observed source lifetimes (tens of hrs.) and establish the alkali migration in the bulk as a diffusion-limited process. The measurements suggest that the faster migration rates (D {approx} 10{sup -5}-10{sup -6} cm{sup 2}/s) occur early during the heating cycle when the dominant species are the neutral alkali atoms. At operating temperatures there is a slower migration rate (D {approx} 10{sup -7} cm{sup 2}/s) due to the dominance of ions, which diffuse by a slower surface diffusion process.
Date: June 1, 2003
Creator: Chacon-Golcher, E.; Kwan, J.W. & Morse, E.C.
Partner: UNT Libraries Government Documents Department

A 1.8 Mev K+ injector for the high current beam transport experiment fusion

Description: For the High Current Beam Transport Experiment (HCX) at LBNL, an injector is required to deliver up to 1.8 MV of 0.6 A K{sup +} beam with an emittance of {approx}1 p-mm-mrad. We have successfully operated a 10-cm diameter surface ionization source together with an electrostatic quadrupole (ESQ) accelerator to meet these requirements. The pulse length is {approx}4 {micro}s, firing at once every 10-15 seconds. By optimizing the extraction diode and the ESQ voltages, we have obtained an output beam with good current density uniformity, except for a small increase near the beam edge. Characterization of the beam emerging from the injector included measurements of the intensity profile, beam imaging, and transverse phase space. These data along with comparison to computer simulations provide the knowledge base for designing and understanding future HCX experiments.
Date: May 20, 2002
Creator: Kwan, J.W.; Bieniosek,F.M.; Henestroza, E.; Prost, L. & Seidl, P.
Partner: UNT Libraries Government Documents Department

Tranverse-field focussing beam transport experiment

Description: The Transverse-Field Focussing (TFF) beam transport and accelerator system developed at LBL is useful for negative-ion -based neutral beam injection due to its unique differential pumping and neutron shielding properties. We have tested the first module of our TFF system transporting H/sup -/ beams up to 80 keV beam energy. The testing addressed the most crucial physics and engineering issues involved in the principles of a TFF system including beam compression and differential gas pumping. At optimum perveance, the present design will transport 4 A/m of H/sup -/ beam at 80 keV beam energy.
Date: October 1, 1986
Creator: Kwan, J.W.; Ackerman, G.D.; Anderson, O.A.; Chan, C.F.; Cooper, W.S.; Soroka, L. et al.
Partner: UNT Libraries Government Documents Department

Comments on cathode contaminants and the LBNL test stand

Description: This report collects information on cathode contaminants we have gathered in the process of operating the LBNL DARHT cathode test stand. Information on contaminants is compiled from several sources. The attachment, ''Practical Aspects of Modern Dispenser Cathodes'', is from Heat Wave Corp. (TB-134) and was originally published in Microwave Journal, September 1979. Cathode contamination depends on both material choices and residual gases. Table 1 of TB-134 lists materials that can poison dispenser cathodes. These include reactive residual gases or vapors such as oxygen, water vapor, benzene, chlorine, fluorine, sulfur, silicon, and most metals other than molybdenum, rhenium, tungsten, and copper. The metals interact with the cathode surface through their vapor pressure. A paper by Nexsen and Turner, J. Appl. Phys. 68, 298-303 (1990) shows the threshold effects of some common residual gases or vapors on cathode performance. The book by Walter H. Kohl, Handbook of Materials and Techniques for Vacuum Devices, also contains useful information on cathodes and poisoning agents. A plot of the vapor pressures and poisoning effect of certain metals (from Kohl) is shown below. Note that the vapor pressure of zinc is 1.1 x 10{sup -8} Torr at 400 K = 127 C, and 2.7 x 10{sup -5} at 500 K = 227 C. By contrast iron reaches a vapor pressure 1 x 10{sup -8} between 800 and 900 C. Therefore it is important to eliminate any brass parts that could exceed a temperature of 100 C. Many structural components of the cathode assembly contain steel. At 500-600 C in an oxygen atmosphere chromium oxide may outgas from the steel. [Cho, et.al., J. Vac. Sci. Technol. A 19, p. 998 (2001)]. Steel may also contain silicon, and sulfur at low concentrations. Therefore use of steel should be limited or avoided at high temperature near the cathode. Materials ...
Date: November 13, 2006
Creator: Bieniosek, F.; Baca, D.; Greenway, W.; Leitner, M. & Kwan, J.W.
Partner: UNT Libraries Government Documents Department

Compact High-Current Heavy-Ion Injector

Description: To provide a compact high-brightness heavy-ion beam source for Heavy Ion Fusion (HIF), we have been experimenting with merging multi-beamlets in an injector which uses an RF plasma source. An array of converging beamlets was used to produce a beam with the envelope radius, convergence, and ellipticity matched to an electrostatic quadrupole (ESQ) channel. Experimental results were in good quantitative agreement with simulation and have demonstrated the feasibility of this concept. The size of a driver-scale injector system using this approach will be several times smaller than one designed using traditional single large-aperture beams. The success of this experiment has possible significant economical and technical impacts on the architecture of HIF drivers.
Date: October 5, 2005
Creator: Westenskow, G. A.; Grote, D. P.; Kwan, J. W. & Bieniosek, F.
Partner: UNT Libraries Government Documents Department

A Compact Multi-Beamlets High Current Injector for HIFDrivers

Description: Using curved electrodes in the injector, an array of converging beamlets can produce a beam with the envelope radius, convergence, and ellipticity matched to an electrostatic quadrupole (ESQ) channel. Experimental results were in good quantitative agreement with simulation and have demonstrated the feasibility of this concept. The size of a driver-scale injector system using this approach will be several times smaller than the one designed using traditional single large-aperture beams, so the success of this experiment has significant economical and technical impacts on the architecture of heavy ion fusion (HIF) drivers.
Date: September 6, 2005
Creator: Kwan, J.W.; Bieniosek, F.M.; Grote, D.P. & Westenskow, G.A.
Partner: UNT Libraries Government Documents Department

Li+ alumino-silicate ion source development for the Neutralized Drift Compression Experiment (NDCX-II)

Description: To heat targets to electron-volt temperatures for the study of warm dense matter with intense ion beams, low mass ions, such as lithium, have an energy loss peak (dE/dx) at a suitable kinetic energy. The Heavy Ion Fusion Sciences (HIFS) program at Lawrence Berkeley National Laboratory will carry out warm dense matter experiments using Li{sup +} ion beam with energy 1.2-4 MeV in order to achieve uniform heating up to 0.1-1 eV. The accelerator physics design of Neutralized Drift Compression Experiment (NDCX-II) has a pulse length at the ion source of about 0.5 {micro}s. Thus for producing 50 nC of beam charge, the required beam current is about 100 mA. Focusability requires a normalized (edge) emittance {approx}2 {pi}-mm-mrad. Here, lithium aluminosilicate ion sources, of {beta}-eucryptite, are being studied within the scope of NDCX-II construction. Several small (0.64 cm diameter) lithium aluminosilicate ion sources, on 70%-80% porous tungsten substrate, were operated in a pulsed mode. The distance between the source surface and the mid-plane of the extraction electrode (1 cm diameter aperture) was 1.48 cm. The source surface temperature was at 1220 C to 1300 C. A 5-6 {micro}s long beam pulsed was recorded by a Faraday cup (+300 V on the collector plate and -300 V on the suppressor ring). Figure 1 shows measured beam current density (J) vs. V{sup 3/2}. A space-charge limited beam density of {approx}1 mA/cm{sup 2} was measured at 1275 C temperature, after allowing a conditioning time of about {approx} 12 hours. Maximum emission limited beam current density of {ge} 1.8mA/cm{sup 2} was recorded at 1300 C with 10-kV extractions. Figure 2 shows the lifetime of two typical sources with space-charge limited beam current emission at a lower extraction voltage (1.75 kV) and at temperature of 1265 {+-} 7 C. These data demonstrate a constant, space-charge ...
Date: April 20, 2011
Creator: LBNL; Roy, P.K.; Greenway, W.; Kwan, J.W.; Seidl, P.A. & Waldron, W.
Partner: UNT Libraries Government Documents Department

Microwave Ion Source and Beam Injection for an Accelerator-drivenNeutron Source

Description: An over-dense microwave driven ion source capable ofproducing deuterium (or hydrogen) beams at 100-200 mA/cm2 and with atomicfraction>90 percent was designed and tested with an electrostaticlow energy beam transport section (LEBT). This ion source wasincorporatedinto the design of an Accelerator Driven Neutron Source(ADNS). The other key components in the ADNS include a 6 MeV RFQaccelerator, a beam bending and scanning system, and a deuterium gastarget. In this design a 40 mA D+ beam is produced from a 6 mm diameteraperture using a 60 kV extraction voltage. The LEBT section consists of 5electrodes arranged to form 2 Einzel lenses that focus the beam into theRFQ entrance. To create the ECR condition, 2 induction coils are used tocreate ~; 875 Gauss on axis inside the source chamber. To prevent HVbreakdown in the LEBT a magnetic field clamp is necessary to minimize thefield in this region. Matching of the microwave power from the waveguideto the plasma is done by an autotuner. We observed significantimprovement of the beam quality after installing a boron nitride linerinside the ion source. The measured emittance data are compared withPBGUNS simulations.
Date: February 15, 2007
Creator: Vainionpaa, J.H.; Gough, R.; Hoff, M.; Kwan, J.W.; Ludewigt,B.A.; Regis, M.J. et al.
Partner: UNT Libraries Government Documents Department

Coaxial Mono-Energetic Gamma Generator for Active Interrogation

Description: Compact mono-energetic photon sources are sought for active interrogation systems to detect shielded special nuclear materials in, for example, cargo containers, trucks and other vehicles. A prototype gamma interrogation source has been designed and built that utilizes the 11B(p,gamma)12C reaction to produce 12 MeV gamma-rays which are near the peak of the photofission cross section. In particular, the 11B(p,gamma)12C resonance at 163 kV allows the production of gammas at low proton acceleration voltages, thus keeping the design of a gamma generator comparatively small and simple. A coaxial design has been adopted with a toroidal-shaped plasma chamber surrounding a cylindrical gamma production target. The plasma discharge is driven by a 2 MHz rf-power supply (capable up to 50 kW) using a circular rf-antenna. Permanent magnets embedded in the walls of the plasma chamber generate a multi-cusp field that confines the plasma and allows higher plasma densities and lower gas pressures. About 100 proton beamlets are extracted through a slotted plasma electrode towards the target at the center of the device that is at a negative 180 kV. The target consists of LaB6 tiles that are brazed to a water-cooled cylindrical structure. The generator is designed to operate at 500 Hz with 20 mu s long pulses, and a 1percent duty factor by pulsing the ion source rf-power. A first-generation coaxial gamma source has been built for low duty factor experiments and testing.
Date: August 1, 2008
Creator: Ludewigt, Bernhard A.; Antolak, A.J.; Henestroza, E.; Leitner, M.; Leung, K.-N.; Waldron, W. et al.
Partner: UNT Libraries Government Documents Department

Heavy Ion Inertial Fusion Energy: Summaries of Program Elements

Description: The goal of the Heavy Ion Fusion (HIF) Program is to apply high-current accelerator technology to IFE power production. Ion beams of mass {approx}100 amu and kinetic energy {>=} 1 GeV provide efficient energy coupling into matter, and HIF enjoys R&D-supported favorable attributes of: (1) the driver, projected to be robust and efficient; see 'Heavy Ion Accelerator Drivers.'; (2) the targets, which span a continuum from full direct to full indirect drive (and perhaps fast ignition), and have metal exteriors that enable injection at {approx}10 Hz; see 'IFE Target Designs'; (3) the near-classical ion energy deposition in the targets; see 'Beam-Plasma Interactions'; (4) the magnetic final lens, robust against damage; see 'Final Optics-Heavy Ion Beams'; and (5) the fusion chamber, which may use neutronically-thick liquids; see 'Liquid-Wall Chambers.' Most studies of HIF power plants have assumed indirect drive and thick liquid wall protection, but other options are possible.
Date: February 28, 2011
Creator: Friedman, A; Barnard, J J; Kaganovich, I; Seidl, P A; Briggs, R J; Faltens, A et al.
Partner: UNT Libraries Government Documents Department