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Three-dimensional heat transfer analysis of the Doublet III beamline calorimeter

Description: A general three-dimensional analysis has been formulated to study the flow of heat in a neutral beam calorimeter. The boundary value problem with an arbitrary incident heat flux has been solved using Fourier analysis and Laplace transform techniques. A general solution has been obtained and subsequently studied using numerical techniques as applied to the particular geometry and incident heat flux conditions of the Doublet III injection system. Negligible errors result in unfolding the incident heat flux through the use of thermocouples located near the rear surface, if data taking is initiated at the proper time and proceeds at a sufficiently rapid rate.
Date: October 1, 1979
Creator: Kamperschroer, J.H. & Pipkins, J.F.
Partner: UNT Libraries Government Documents Department

Doublet III neutral beam test tank design

Description: A tank has been designed for testing the Doublet III Neutral Beam Injector which simulates the entrance and pressure conditions of the Doublet III vacuum vessel. The cylindrical shape vacuum vessel is the same size as the neutral beam injector vessel. Contained inside are a cylindrical cryopanel, a V-shaped calorimeter, and a retractable sample-holding device to be used for beam armor proof testing. The cryopanel has 4.2 m of surface for pumping the hydrogen load created by beam impingement on the calorimeter. A tank pressure of 1.3 x 10/sup -2/-1.3 x 10/sup -6/ Pa (10/sup -4/-10/sup -8/ torr) is to be maintained to simulate the Doublet III vessel pressure conditions.
Date: March 1, 1980
Creator: Doll, D.W.; Kamperschroer, J.H. & Bailey, E.W.
Partner: UNT Libraries Government Documents Department

Doublet III neutral beam injector test tank cryopanel design

Description: A simple condensing cryopanel has been designed for the Doublet III neutral beam test tank with a 320,000 liters per second pumping capacity for hydrogen. This maintains a vacuum in the test tank which simulates the Doublet III vessel, 1.3 x 10/sup -3/ Pa (approx.10/sup -5/ torr). The hydrogen gas load comes from the beam striking the test tank calorimeter and amounts to about 7.2 torr liters per second. The cryopanel is cylindrical shaped with a liquid helium (LHe) surface that pumps through liquid nitrogen (LN) cooled aluminum chevrons located in squirrel-cage fashion around the inside surface of the cylinder. The LHe cooled surface is a smooth cylinder 2.09m in diameter by .69m long with LHe flowing in a approx. 1mm annular space between concentric cylinders. The chevrons which are not blackened are cooled from each end with LN flowing in ring manifolds that serve as the primary cryopanel structure. The LHe is force fed at 55.2 kPa remaining in the liquid phase through the panel. External heat exchanger capability permits use of helium at 3.8 to 4.2/sup 0/K. Normal operating flow rate is 1.4 g/sec for a heat load expected to be 12.2 W total.
Date: March 1, 1980
Creator: Doll, D.W.; Kamperschroer, J.H. & Arend, P.V.
Partner: UNT Libraries Government Documents Department

Optical pyrometry applied to the neutral beam interlock system for Doublet III

Description: The neutral beam injection system for Doublet III has been designed with curved grid ion sources and near-perpendicular injection. Given these conditions the neutral beam power loading on the inside wall of the vacuum chamber can be as high as 5 kW/cm/sup 2/ if no plasma is present. To protect the tokamak against the neutral beam under conditions where the plasma density is diminished, a fast infrared detector system is being developed. This device will monitor the beam hot spot on the armor plate and provide an interrupt signal when the temperature rises above a present value. The characteristics of a detector able to meet the desired performance specifications while operating in a tokamak environment are described.
Date: October 1, 1979
Creator: McMahon, T.R.; Kamperschroer, J.H. & Colleraine, A.P.
Partner: UNT Libraries Government Documents Department

Armor plate protection for the Doublet III vacuum vessel for neutral beam heating

Description: The design of vacuum vessel armor plate for neutral beam systems presents a number of challenges to the engineer. Heat fluxes of several hundred watts/cm/sup 2/ must be handled on a routine basis during normal plasma operations, and a factor of ten increase in these fluxes can occur during plasma disruptions. At the present time, a graphite tile system appears to be the best candidate for such a situation. Heat fluxes in excess of 4 kW/cm/sup 2/ can be routinely sustained and the material sputtered or evaporated from the surface has a low atomic number. The system proposed for Doublet III will provide valuable data for the designers of future fusion reactors and will also provide proof-of-principle demonstrations for such machines as TFTR and JET.
Date: October 1, 1979
Creator: Colleraine, A.P.; Kamperschroer, J.H. & Pipkins, J.F.
Partner: UNT Libraries Government Documents Department

Target Diagnostic Instrument-Based Controls Framework for the National Ignition Facility (NIF)

Description: The extreme physics of targets shocked by NIF's 192-beam laser are observed by a diverse suite of diagnostics including optical backscatter, time-integrated and gated X-ray sensors, and laser velocity interferometry. Diagnostics to diagnose fusion ignition implosion and neutron emissions are being planned. Many diagnostics will be developed by collaborators at other sites, but ad hoc controls could lead to unreliable and costly operations. An instrument-based controls (I-BC) framework for both hardware and software facilitates development and eases integration. Each complex diagnostic typically uses an ensemble of electronic instruments attached to sensors, digitizers, cameras, and other devices. In the I-BC architecture each instrument is interfaced to a low-cost Windows XP processor and Java application. Each instrument is aggregated with others as needed in the supervisory system to form an integrated diagnostic. The Java framework provides data management, control services and operator GUI generation. I-BCs are reusable by replication and reconfiguration for specific diagnostics in XML. Advantages include minimal application code, easy testing, and better reliability. Collaborators save costs by assembling diagnostics with existing I-BCs. This paper discusses target diagnostic instrumentation used on NIF and presents the I-BC architecture and framework.
Date: October 3, 2007
Creator: Shelton, R. T.; O'Brien, D. W.; Kamperschroer, J. H. & Nelson, J. R.
Partner: UNT Libraries Government Documents Department

Target Diagnostic Control System Implementation for the National Ignition Facility

Description: The extreme physics of targets shocked by NIF's 192-beam laser are observed by a diverse suite of diagnostics. Many diagnostics are being developed by collaborators at other sites, but ad hoc controls could lead to unreliable and costly operations. A Diagnostic Control System (DCS) framework for both hardware and software facilitates development and eases integration. Each complex diagnostic typically uses an ensemble of electronic instruments attached to sensors, digitizers, cameras, and other devices. In the DCS architecture each instrument is interfaced to a low-cost Windows XP processor and Java application. Each instrument is aggregated with others as needed in the supervisory system to form an integrated diagnostic. The Java framework provides data management, control services and operator GUI generation. DCS instruments are reusable by replication with reconfiguration for specific diagnostics in XML. Advantages include minimal application code, easy testing, and high reliability. Collaborators save costs by assembling diagnostics with existing DCS instruments. This talk discusses target diagnostic instrumentation used on NIF and presents the DCS architecture and framework.
Date: May 12, 2010
Creator: Shelton, R T; Kamperschroer, J H; Lagin, L J; Nelson, J R & O'Brien, D W
Partner: UNT Libraries Government Documents Department

Gas utilization in TFTR (Tokamak Fusion Test Reactor) neutral beam injectors

Description: Measurements of gas utilization in a test TFTR neutral beam injector have been performed to study the feasibility of running tritium neutral beams with existing ion sources. Gas consumption is limited by the restriction of 50,000 curies of T/sub 2/ allowed on site. It was found that the gas efficiency of the present long-pulse ion sources is higher than it was with previous short-pulse sources. Gas efficiencies were studied over the range of 35 to 55%. At the high end of this range the neutral fraction of the beam fell below that predicted by room temperature molecular gas flow. This is consistent with observations made on the JET injectors, where it has been attributed to beam heating of the neutralizer gas and a concomitant increase in conductance. It was found that a working gas isotope exchange from H/sub 2/ to D/sub 2/ could be accomplished on the first beam shot after changing the gas supply, without any intermediate preconditioning. The mechanism believed responsible for this phenomenon is heating of the plasma generator walls by the arc and a resulting thermal desorption of all previously adsorbed and implanted gas. Finally, it was observed that an ion source conditioned to 120 kV operation could produce a beam pulse after a waiting period of fourteen hours by preceding the beam extraction with several hi-pot/filament warm-up pulses, without any gas consumption. 18 refs., 7 figs., 2 tabs.
Date: August 1, 1987
Creator: Kamperschroer, J.H.; Gammel, G.M.; Kugel, H.W.; Grisham, L.R.; Stevenson, T.N.; von Halle, A. et al.
Partner: UNT Libraries Government Documents Department

Doppler-shift proton fraction measurement on a CW proton injector

Description: A spectrometer/Optical Multi-channel Analyzer has been used to measure the proton fraction of the cw proton injector developed for the Accelerator Production of Tritium (APT) and the Low Energy Demonstration Accelerator (LEDA) at Los Alamos. This technique, pioneered by the Lawrence Berkeley National Laboratory (LBNL), was subsequently adopted by the international fusion community as the standard for determining the extracted ion fractions of neutral beam injectors. Proton fractions up to 95 {+-} 3% have been measured on the LEDA injector. These values are in good agreement with results obtained by magnetically sweeping the ion beam, collimated by a slit, across a Faraday cup. Since the velocity distribution of each beam species is measured, it also can be used to determine beam divergence. While divergence has not yet been ascertained due to the wide slit widths in use, non-Gaussian distributions have been observed during operation above the design-matched perveance. An additional feature is that the presence of extracted water ions can be observed. During ion source conditioning at 75 kV, an extracted water fraction > 30% was briefly observed.
Date: December 31, 1998
Creator: Kamperschroer, J.H.; Sherman, J.D.; Zaugg, T.J.; Arvin, A.H.; Bolt, A.S. & Richards, M.C.
Partner: UNT Libraries Government Documents Department

Experience with deuterium-tritium plasmas heated by high power neutral beams

Description: The Tokamak Fusion Test Reactor has operated since November of 1993 with a deuterium-tritium fuel mixture for selected discharges. The majority of the tritium has been introduced as energetic neutral atoms of up to 120 keV injected by the neutral beam systems, with some of the twelve ion sources run on pure tritium and some on deuterium to optimize the fuel mixture in the core plasma. A maximum beam power of 39.6 megawatts has been injected, and deuterium-tritium fusion power production has reached 10.7 megawatts, achieving central fusion power densities comparable to or greater than those expected for the International Thermonuclear Reactor, and allowing the first studies of fusion-produced alpha particle behavior in reactor grade plasmas. Energy confinement in deuterium-tritium plasmas is better than in similar deuterium plasmas for most plasma regimes. Innovative techniques to manipulate the plasma current and pressure profiles are permitting studies of enhanced confinement regimes.
Date: 1996
Creator: Grisham, L. R.; Kamperschroer, J. H.; O`Connor, T.; Oldaker, M.; Stevenson, T. & Von Halle, A.
Partner: UNT Libraries Government Documents Department

Measurement of ion profiles in TFTR neutral beamlines

Description: A technique is described whereby the ion dumps inside the TFTR Neutral Beam Test Stand were used to measure thermal profiles of the full-, half-, and third-energy ions. 136 thermocouples were installed on the full-energy ion dump, allowing full beam contours. Additional linear arrays across the widths of the half- and third-energy ion dumps provided a measure of the shape, in the direction parallel to the grid rails, of the half- and third-energy ions, and, hence, of the molecular ions extracted from the source. As a result of these measurements it was found that the magnet was more weakly focusing, by a factor of two, than expected, explaining past overheating of the full-energy ion dump. Hollow profiles on the half- and third-energy ion dumps were observed, suggesting that extraction of D{sub 2}+ and D{sub 3}+ are primarily from the edge of the ion source. If extraction of half-energy ions is from the edge of the accelerator, a divergence parallel to the grid rails of 0.6{degrees}{plus minus}0.1{degrees} results. It is postulated that a nonuniform gas profile near the accelerator is the cause of the hollow partial-energy ion profiles; the pressure being depressed over the accelerator by particles passing through this highly transparent structure. Primary electrons reaching the accelerator produce nonuniform densities of D{sub 2}+ through the ionization of this across the full-energy dump was examined as a means of reducing the power density. By unbalancing the current in the two coils of the magnet, on a shot by shot basis, by up to 2:1 ratio, it was possible to move the centerline of the full-energy ion beam sideways by {approximately}12.5 cm. The adoption of such a technique, with a ramp of the coil imbalance from 2:1 to 1:2 over a beam pulse, could reduce the power density by a factor of ...
Date: February 1, 1992
Creator: Kamperschroer, J.H.; Grisham, L.R.; Kugel, H.W.; O'Connor, T.E.; Stevenson, T.N.; von Halle, A. et al.
Partner: UNT Libraries Government Documents Department

Measurement of ion profiles in TFTR neutral beamlines

Description: A technique is described whereby the ion dumps inside the TFTR Neutral Beam Test Stand were used to measure thermal profiles of the full-, half-, and third-energy ions. 136 thermocouples were installed on the full-energy ion dump, allowing full beam contours. Additional linear arrays across the widths of the half- and third-energy ion dumps provided a measure of the shape, in the direction parallel to the grid rails, of the half- and third-energy ions, and, hence, of the molecular ions extracted from the source. As a result of these measurements it was found that the magnet was more weakly focusing, by a factor of two, than expected, explaining past overheating of the full-energy ion dump. Hollow profiles on the half- and third-energy ion dumps were observed, suggesting that extraction of D{sub 2}+ and D{sub 3}+ are primarily from the edge of the ion source. If extraction of half-energy ions is from the edge of the accelerator, a divergence parallel to the grid rails of 0.6{degrees}{plus_minus}0.1{degrees} results. It is postulated that a nonuniform gas profile near the accelerator is the cause of the hollow partial-energy ion profiles; the pressure being depressed over the accelerator by particles passing through this highly transparent structure. Primary electrons reaching the accelerator produce nonuniform densities of D{sub 2}+ through the ionization of this across the full-energy dump was examined as a means of reducing the power density. By unbalancing the current in the two coils of the magnet, on a shot by shot basis, by up to 2:1 ratio, it was possible to move the centerline of the full-energy ion beam sideways by {approximately}12.5 cm. The adoption of such a technique, with a ramp of the coil imbalance from 2:1 to 1:2 over a beam pulse, could reduce the power density by a factor of {ge}1.5.
Date: February 1, 1992
Creator: Kamperschroer, J. H.; Grisham, L. R.; Kugel, H. W.; O`Connor, T. E.; Stevenson, T. N.; von Halle, A. et al.
Partner: UNT Libraries Government Documents Department

Multiple track Doppler-shift spectroscopy system for TFTR neutral beam injectors

Description: A Doppler-shift spectroscopy system has been installed on the TFTR neutral beam injection system to measure species composition during both conditioning and injection pulses. Two intensified vidicon detectors and two spectrometers are utilized in a system capable of resolving data from up to twelve ion sources simultaneously. By imaging the light from six ion sources onto one detector, a cost-effective system has been achieved. Fiber optics are used to locate the diagnostic in an area remote from the hazards of the tokamak test cell allowing continuous access, and eliminating the need for radiation shielding of electronic components. Automatic hardware arming and interactive data analysis allow beam composition to be computed between tokamak shots for use in analyzing plasma heating experiments. Measurements have been made using lines of sight into both the neutralizer and the drift duct. Analysis of the data from the drift duct is both simpler and more accurate since only neutral particles are present in the beam at this location. Comparison of the data taken at these two locations reveals the presence of partially accelerated particles possessing an estimated 1/e half-angle divergence of 15/sup 0/ and accounting for up to 30% of the extracted power.
Date: September 1, 1986
Creator: Kamperschroer, J.H.; Kugel, H.W.; Reale, M.A.; Hayes, S.L.; Johnson, G.A.; Lowrance, J.L. et al.
Partner: UNT Libraries Government Documents Department

Operation of a TFTR ion source with a ground potential gas feed into the neutralizer

Description: TFTR long pulse ion sources have been operated with gas fed only into the neutralizer. Gas for the plasma generator entered through the accelerator rather than directly into the arc chamber. This modification has been proposed for tritium beam operation to locate control electronics at ground potential and to simplify tritium plumbing. Source operation with this configuration and with the nominal gas system which feeds gas into both the ion source and the center of the neutralizer are compared. Comparison is based upon accelerator grid currents, beam composition, and neutral power delivered to the calorimeter. Charge exchange in the accelerator can be a significant loss mechanism in both systems at high throughput. A suitable operating point with the proposed system was found that requires 30% less gas than used presently. The extracted D{sup +}, D{sub 2}{sup +}, and D{sub 3}{sup +} fractions of the beam were found to be a function of the gas throughput; at similar throughputs, the two gas feed systems produced similar extracted ion fractions. Operation at the proposed gas efficient point results in a small reduction (relative to the old high throughput mode) in the extracted D{sup +} fraction of the beam from 77% to 71%, with concomitant changes in the D{sub 2}{sup +} fraction from 18% to 26%, and 6% to 3% for D{sub 3}{sup +}. 26 refs., 7 figs.
Date: July 1, 1991
Creator: Kamperschroer, J.H.; Dudek, L.E.; Grisham, L.R.; Newman, R.A.; O'Conner, T.E.; Stevenson, T.N. et al.
Partner: UNT Libraries Government Documents Department

TFTR (Tokamak Fusion Test Reactor) neutral beam injected power measurement

Description: Energy flow within TFTR neutral beamlines is measured with a waterfall calorimetry system capable of simultaneously measuring the energy deposited within four heating beamlines (three ion sources each), or of measuring the energy deposited in a separate neutral beam test stand. Of the energy extracted from the ion source in the well instrumented test stand, 99.5 +- 3.5% can be accounted for. When the ion deflection magnet is energized, however, 6.5% of the extracted energy is lost. This loss is attributed to a spray of devious particles onto unmonitored surfaces. A 30% discrepancy is also observed between energy measurements on the internal beamline calorimeter and energy measurements on a calorimeter located in the test stand target chamber. Particle reflection from the flat plate calorimeter in the target chamber, which the incident beam strikes at a near-grazing angle of 12/degree/, is the primary loss of this energy. A slight improvement in energy accountability is observed as the beam pulse length is increased. This improvement is attributed to systematic error in the sensitivity of the energy measurement to small fluctuations on the supply water temperature. An overall accuracy of 15% is estimated for the total power injected into TFTR. Contributions to this error are uncertainties in the beam neutralization efficiency, reionization and beam scrape-off in the drift duct, and fluctuations in the temperature of the supply water. 28 refs., 9 figs., 1 tab.
Date: May 1, 1989
Creator: Kamperschroer, J.H.; Grisham, L.R.; Dudek, L.E.; Gammel, G.M.; Johnson, G.A.; Kugel, H.W. et al.
Partner: UNT Libraries Government Documents Department

Temporal behavior of neutral particle fluxes in TFTR (Tokamak Fusion Test Reactor) neutral beam injectors

Description: Data from an E {parallel} B charge exchange neutral analyzer (CENA), which views down the axis of a neutral beamline through an aperture in the target chamber calorimeter of the TFTR neutral beam test facility, exhibit two curious effects. First, there is a turn-on transient lasting tens of milliseconds having a magnitude up to three times that of the steady-state level. Second, there is a 720 Hz, up to 20% peak-to-peak fluctuation persisting the entire pulse duration. The turn-on transient occurs as the neutralizer/ion source system reaches a new pressure equilibrium following the effective ion source gas throughput reduction by particle removal as ion beam. Widths of the transient are a function of the gas throughput into the ion source, decreasing as the gas supply rate is reduced. Heating of the neutalizer gas by the beam is assumed responsible, with gas temperature increasing as gas supply rate is decreased. At low gas supply rates, the transient is primarliy due to dynamic changes in the neutralizer line density and/or beam species composition. Light emission from the drift duct corroborate the CENA data. At high gas supply rates, dynamic changes in component divergence and/or spatial profiles of the source plasma are necessary to explain the observations. The 720 Hz fluctuation is attributed to a 3% peak-to-peak ripple of 720 Hz on the arc power supply amplified by the quadratic relationship between beam divergence and beam current. Tight collimation by CENA apertures cause it to accept a very small part of the ion source's velocity space, producing a signal linearly proportional to beam divergence. Estimated fluctuations in the peak power density delivered to the plasma under these conditions are a modest 3--8% peak to peak. The efffects of both phenomena on the injected neutral beam can be ameliorated by careful operion of the ...
Date: September 1, 1989
Creator: Kamperschroer, J.H.; Gammel, G.M.; Roquemore, A.L.; Grisham, L.R.; Kugel, H.W.; Medley, S.S. et al.
Partner: UNT Libraries Government Documents Department

Operation of TFTR neutral beams with heavy ions

Description: High Z neutral atoms have been injected into TFTR plasmas in an attempt to enhance plasma confinement through modification of the edge electric field. TFTR ion sources have extracted 9 A of 62 keV Ne{sup +} for up to 0.2 s during injection into deuterium plasmas, and for 0.5 s during conditioning pulses. Approximately 400 kW of Ne{sup 0} have been injected from each of two ion sources. Operation was at full bending magnet current, with the Ne{sup +} barely contained on the ion dump. Beamline design modifications to permit operation up to 120 keV with krypton or xenon are described. Such ions are too massive to be deflected up to the ion dump. The plan, therefore, is to armor those components receiving these ions. Even with this armor, modest increases in the bending magnet current capability are necessary to safely reach 120 kV with Kr or Xe. Information relevant to heavy ion operation was also acquired when several ion sources were inadvertently operated with water contamination. Spectroscopic analysis of certain pathological pulses indicate that up to 6% of the extracted ions were water. After dissociation in the neutralizer, water yields oxygen ions which, as with Ne, Kr, and Xe, are under-deflected by the magnet. Damage to a calorimeter scraper, due to the focal properties of the magnet, has resulted. A magnified power density of 6 KW/cm{sup 2} for 2 s, from {approximately} 90 kW of O{sup +}, is the suspected cause. 11 refs., 4 figs.
Date: July 1, 1991
Creator: Kamperschroer, J.H.; Stevenson, T.N.; Wright, K.E.; Dudek, L.E.; Grisham, L.R.; Newman, R.A. et al.
Partner: UNT Libraries Government Documents Department

Particle reflection and TFTR neutral beam diagnostics

Description: Determination of two critical neutral beam parameters, power and divergence, are affected by the reflection of a fraction of the incident energy from the surface of the measuring calorimeter. On the TFTR Neutral Beam Test Stand, greater than 30% of the incident power directed at the target chamber calorimeter was unaccounted for. Most of this loss is believed due to reflection from the surface of the flat calorimeter, which was struck at a near grazing incidence (12{degrees}). Beamline calorimeters, of a V''-shape design, while retaining the beam power, also suffer from reflection effects. Reflection, in this latter case, artificially peaks the power toward the apex of the V'', complicating the fitting technique, and increasing the power density on axis by 10 to 20%; an effect of import to future beamline designers. Agreement is found between measured and expected divergence values, even with 24% of the incident energy reflected.
Date: April 1, 1992
Creator: Kamperschroer, J.H.; Grisham, L.R.; Kugel, H.W.; O'Connor, T.E.; Newman, R.A.; Stevenson, T.N. et al.
Partner: UNT Libraries Government Documents Department

Low Z impurity ion extraction from TFTR ion sources

Description: TFTR deuterium neutral beams have been operated unintentionally with significant quantities of extracted water ions. Water has been observed with an Optical Multichannel Analyzer (OMA) during beam extraction when small water leaks were present within the arc chamber. These leaks were thermally induced with the contamination level increasing linearly with pulse length. 6% of the beam current was attributed to water ions for the worst leak, corresponding to an instantaneous value of 12% at the end of a 1.5 s pulse. A pre-calorimeter collimator was damaged as a result of this operation. A similar contamination is observed during initial operation of ion sources exposed to air. This latter contamination is attributed to the synthesis, from adsorbed air, of either D[sub 2]O or the indistinguishable ND[sub 3]. Initial operation of new ion sources typically produces a contamination level of [approximately]2%. These impurities are reduced to undetectable levels after 50 to 100 beam pulses. Once a water molecule is present in the plasma generator, it is predominantly ionized rather than dissociated, resulting in the extraction of only trace amounts of hydrogenated ions. The addition of water to the extracted beam also reduces the optimum perveance, moving the typical underdense operating point closer to optimum, causing the frequency of grid faults to increase. Close to 90% of the water extracted from ion sources with water leaks was deuterated, implying that the potential exists for the production of tritiated water during TFTR's forthcoming DT operation. Isotope exchange in the plasma generator takes place rapidly and is believed to be surface catalyzed. The primary concern is with O implanted into beam absorbers recombining with tritium, and the subsequent hold up of T[sub 2]O on cryopanels. Continuous surveillance with the OMA diagnostic during DT operation will ensure that ion sources with detectable water are not operated ...
Date: April 1, 1993
Creator: Kamperschroer, J.H.; Grisham, L.R.; Newman, R.A.; O'Connor, T.E.; Stevenson, T.N.; von Halle, A. et al.
Partner: UNT Libraries Government Documents Department

Conceptual design of the neutral beamline for TPX long pulse operation

Description: The Tokamak Physics Experiment (TPX) will require a minimum of 8.0 megawatts of Neutral Beam beating power to be injected into the plasma for pulse lengths up to one thousand (1000) seconds to meet the experimental objectives. The Neutral Beam Injection System (NBIS) for initial operation on TPX will consist of one neutral beamline (NBL) with three Ion sources. Provisions will be made for a total of three NBLs. The NBIS will provide S.S MW of 120 keV D{sup 0} and 2.S MW of partial-energy D{sup 0} at 60 keV and 40 keV. The system also provides for measuring the neutral beam power, limits excess cold gas from entering the torus, and provides independent power, control, and protection for each individual ion source and accelerating structure. The Neutral Beam/Torus Connecting Duct (NB/TCD) includes a vacuum valve, an electrical insulating break, alignment bellows, vacuum seals, internal energy absorbing protective elements, beam diagnostics and bakeout capability. The NBL support structure will support the NBL, which will weigh approximately 80 tons at the proper elevation and withstand a seismic event. The NBIS currently operational on the Tokamak Fusion Test Reactor (TFTR) at the Princeton Plasma Physics Laboratory (PPPL) is restricted to injection pulse lengths of two (2) seconds by the limited capability of various energy absorbers. This paper describes the modifications and improvements which will be implemented for the TFTR Neutral Beamlines and the NB/TCD to satisfy the TPX requirements.
Date: November 1, 1993
Creator: Wright, K. E.; Dahlgren, F.; Fan, H. M.; Grisham, L. R.; Hammersand, F. G.; Kamperschroer, J. H. et al.
Partner: UNT Libraries Government Documents Department

BEAM-PROFILE INSTRUMENTATION FOR BEAM-HALO MEASUREMENT : OVERALL DESCRIPTION AND OPERATION

Description: Within the halo experiment presently being conducted at the Low Energy Demonstration Accelerator at Los Alamos National Laboratory, specific beam instruments that acquire horizontally and vertically projected particle-density distributions out to greater than 10{sup 5}:1 dynamic range are located throught the 52-magnet halo lattice.
Date: January 1, 2001
Creator: Gilpatrick, J. D. (John Douglas); Barr, D. S. (Dean S.); Day, L. A. (Lisa A.); Kerstiens, D. M. (Debora M.); Stettler, M. W. (Matthew W.); Valdiviez, R. (Robert) et al.
Partner: UNT Libraries Government Documents Department

BEAM-PROFILE INSTRUMENTATION FOR BEAM-HALO MEASUREMENT : OVERALL DESCRIPTION, OPERATION, AND BEAM DATA.

Description: The halo experiment presently being conducted at the Low Energy Demonstration Accelerator (LEDA) at Los Alamos National Laboratory (LANL) has specific instruments that acquire horizontally and vertically projected particle-density beam distributions out to greater than 10{sup 5}:1 dynamic range. They measure the core of the distributions using traditional wire scanners, and the tails of the distribution using water-cooled graphite scraping devices. The wire scanner and halo scrapers are mounted on the same moving frame whose location is controlled with stepper motors. A sequence within the Experimental Physics and Industrial Control System (EPICS) software communicates with a National Instrument LabVIEW virtual instrument to control the motion and location of the scanner/scraper assembly. Secondary electrons from the wire scanner 0.03-mm carbon wire and protons impinging on the scraper are both detected with a lossy-integrator electronic circuit. Algorithms implemented within EPICS and in Research Systems Interactive Data Langugage (IDL) subroutines analyse and plot the acquired distributions. This paper describes this beam profile instrument, describes their experience with its operation, compares acquired profile data with simulations, and discusses various beam profile phenomena specific to the halo experiment.
Date: January 1, 2001
Creator: Gilpatrick, J. D. (John Douglas); Barr, D. S. (Dean S.); Day, L. A. (Lisa A.); Stettler, M. W. (Matthew W.); Valdiviez, R. (Robert); Gruchalla, M. (Michael) et al.
Partner: UNT Libraries Government Documents Department

Comparison of Simulations with Measurements for the LEDA LEBT H

Description: The Low-Energy Demonstration Accelerator (LEDA) injector is designed to provide 75-keV, 110-mA, proton beams for the LEDA RFQ. After testing the LEDA injector using a 1.25-MeV, CW RFQ, the authors shortened the low-energy beam transport (LEBT) to 2.69 m, replaced the first LEBT solenoid with one that has a shorter length but the same focusing power, and installed and operated the LEDA injector in the beam tunnel. In this paper the authors use the TRACE, SCHAR, and PARMELA computer codes to model the proton beam for the as-installed LEBT and the authors compare the results of these simulations with the LEBT beam measurements. They use the computer code PARMTEQM to transport the SCHAR- and PARMELA-generated beams through the RFQ so that they can compare the predicted RFQ performance with the measured RFQ performance. For a 100-mA, 0.239-{rho}-mm-mrad input beam, PARMTEQM predicts the LEDA RFQ transmission will be 92.2%.
Date: March 29, 1999
Creator: Smith, H.V.; Figueroa, T.L.; Hansborough, L.D.; Harrington, M.P.; Johnson, K.F.; Kerstiens, D.M. et al.
Partner: UNT Libraries Government Documents Department