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Applications of decelerated ions

Description: Many facilities whose sole purpose had been to accelerate ion beams are now becoming decelerators as well. The development and current status of accel-decel operations is reviewed here. Applications of decelerated ions in atomic physics experiments are discussed.
Date: March 1, 1985
Creator: Johnson, B.M.
Partner: UNT Libraries Government Documents Department

Two accel/decel experiments: electron capture for 6 to 20 MeV S/sup 10/-/sup 16 +/ on He and Ar and interference effects in MO K x-ray spectra for 5, 10, and 20 MeV Cl/sup 16 +/ on Ar

Description: The recent development of four-stage accel-decel operation of the dual MP tandem accelerators at Brookhaven National Laboratory has made it possible to extend atomic collision experiments over an unprecedented range of high charge states and low velocities. Briefly, this mode of operation uses the first MP tandem conventionally for two stages of acceleration, then with a negative terminal voltage the second MP tandem provides a third stage of acceleration to high velocity, stripping to high charge state and a final stage of deceleration to low velocity. Details of operation and recent upgrades of the facility were reviewed earlier. An overview of present capabilities and the results of two experimental studies using accel-decel beams are presented here.
Date: January 1, 1983
Creator: Johnson, B.M.
Partner: UNT Libraries Government Documents Department

Numerical Tests and Properties of Waves in Radiating Fluids

Description: We discuss the properties of an analytical solution for waves in radiating fluids, with a view towards its implementation as a quantitative test of radiation hydrodynamics codes. A homogeneous radiating fluid in local thermodynamic equilibrium is periodically driven at the boundary of a one-dimensional domain, and the solution describes the propagation of the waves thus excited. Two modes are excited for a given driving frequency, generally referred to as a radiative acoustic wave and a radiative diffusion wave. While the analytical solution is well known, several features are highlighted here that require care during its numerical implementation. We compare the solution in a wide range of parameter space to a numerical integration with a Lagrangian radiation hydrodynamics code. Our most significant observation is that flux-limited diffusion does not preserve causality for waves on a homogeneous background.
Date: September 3, 2009
Creator: Johnson, B M & Klein, R I
Partner: UNT Libraries Government Documents Department

Synchrotron radiation production and trapping of highly charged ions

Description: Wiggler-enhanced synchrotron radiation will soon be available at dedicated facilities such as the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. Two recent proposals to study highly-charged ions produced by successive photoionization with broad-band synchrotron radiation are based on the design parameters of the NSLS x-ray ring. Previous calculations indicated that in a suitable Kingdon trap, concentrations of 5 x 10/sup 7/ Ar/sup 18 +/ ions per cm can be attained in a few seconds trapping time and that in a Penning trap 5 x 10/sup 3/ Ar/sup 17 +/ ions could be stored at near thermal energies (300/sup 0/K) to study, for example, charge transfer collision processes for cold, highly-charged ions. Here the previous work is reviewed and the earlier calculations are extended. The addition of an axial magnetic field to a Kingdon trap is shown to improve expected PHOBIS performance.
Date: September 1, 1984
Creator: Johnson, B.M.; Jones, K.W. & Meron, M.
Partner: UNT Libraries Government Documents Department

Informal proposal for an Atomic Physics Facility at the National Synchrotron Light Source

Description: An Atomic Physics Facility (APF) for experiments that will use radiation from a superconducting wiggler on the NSLS X-13 port is described. The scientific justification for the APF is given and the elements of the facility are discussed. It is shown that it will be possible to conduct a uniquely varied set of experiments that can probe most aspects of atomic physics. A major component of the proposal is a heavy-ion storage ring capable of containing ions with energies of about 10 MeV/nucleon. The ring can be filled with heavy ions produced at the BNL MP Tandem Laboratory or from independent ion-source systems. A preliminary cost estimate for the facility is presented.
Date: January 1, 1986
Creator: Jones, K.W.; Johnson, B.M. & Meron, M.
Partner: UNT Libraries Government Documents Department

Technical and economic assessment of the use of ammonia expanders for energy recovery in air-cooled power plants

Description: Binary cycle power plants have been the subject of much discussion among engineers and scientists for nearly 100 years. Current economic and environmental concerns have stimulated new interest and research. Ammonia has been recommended by other studies as the leading contender for use as simply the heat rejection medium in an air-cooled power plant. This study investigates the technical feasibility and economic potential of including an expander in the heat rejection system of an air-cooled power plant. The expander would be used during certain parts of the year to increase the total output of the power plant. Five different plant locations (Miami, San Francisco, Bakersfield, Chicago, Anchorage) were investigated to show the effect which climate has on the economic potential of this ammonia bottoming cycle. The study shows that the expected energy costs for the bottoming cycle only will be less than 50 mills/kWh for any of the five plant locations. This cost assumes that an ammonia phase-change heat rejection system is already a part of the existing plant. The colder climates of Chicago and Anchorage demonstrate an even smaller energy cost of less than 15 mills/kWh. Further investigation of the concept is merited to substantiate these costs and determine the needed technology.
Date: July 1, 1982
Creator: Hauser, S.G.; Hane, G.J. & Johnson, B.M.
Partner: UNT Libraries Government Documents Department

Atomic physics with high-brightness synchrotron x-ray sources

Description: A description of atomic physics experiments that we intend to carry out at the National Synchrotron Light Source is given. Emphasis is given to work that investigates the properties of multiply charged ions. The use of a synchrotron storage ring for highly charged heavy ions is proposed as a way to produce high current beams which will make possible experiments to study the photoexcitation and ionization of multiply charged ions for the first time. Experiments along the same lines which are feasible at the proposed Advanced Light Source are considered briefly. 7 refs., 2 figs.
Date: November 1, 1985
Creator: Jones, K.W.; Johnson, B.M. & Meron, M.
Partner: UNT Libraries Government Documents Department

Atomic collision experiments utilizing low-velocity, highly-charged ion beams

Description: Intense beams of highly-stripped ions are now routinely produced at low velocities using the Brookhaven dual MP-tandens in a unique four-stage accel/decel mode. This mode of operation combines three stages of acceleration, stripping at high energy, and one stage of deceleration to near-zero velocity. To date, experiments have used 10-100 nA beams of bare and few-electron heavy ions at energies as low as 0.2 MeV/amu, and upgrades of the facility should push the lower limit below 0.1 MeV/amu. Recent experiments, such as measurements of charge transfer and x-ray production for S/sup 6-16+/ on He and Ar at 6 to 20 MeV and P(b) measurements for MO x-rays produced in Cl/sup 16 +/ + Ar collisions at 20, 10, and 5 MeV have demonstrated the usefulness of highly-stripped, low-velocity projectiles. These experiments and a few possibilities for future experiments are discussed.
Date: January 1, 1982
Creator: Johnson, B.M.; Jones, K.W. & Meron, M.
Partner: UNT Libraries Government Documents Department

Experiments with a synchrotron x-ray source and conventional, ECR, and storage-ring ion sources

Description: The present intensities of photon beams produced by synchrotron-radiation x-ray sources and of ion beams from conventional ion sources, electron-cyclotron resonance ion sources (ECRIS), and cooled heavy-ion storage rings (CHISR) make possible investigations of photoionization and photoexcitation processes that have not previously been feasible. An evaluation of the signal and background rates for experiments that employ the different types of ion sources is given here. 11 refs., 3 figs., 6 tabs.
Date: January 1, 1988
Creator: Jones, K.W.; Johnson, B.M. & Meron, M.
Partner: UNT Libraries Government Documents Department

Present and future directions of atomic physics research with multiply-charged ions at Brookhaven National Laboratory

Description: Atomic physics research with multiply-charged ions is now in progress using ion beams from the Brookhaven Double MP-Tandem van de Graaff facility. In the near future, experiments will start using ions produced by photons from the National Synchrotron Light Source (NSLS). Examples of typical experiments are discussed to illustrate the comprehensive nature of these facilities. Plans for future expansion by addition of a CRYEBIS type ion source coupled to a heavy-ion storage ring for use in crossed-beam experiments at the NSLS are discussed. 18 refs., 8 figs.
Date: March 1, 1985
Creator: Jones, K.W.; Johnson, B.M. & Meron, M.
Partner: UNT Libraries Government Documents Department

Charge state evolution in an ion trap irradiated by VUV synchrotron radiation

Description: The energies of photons obtainable from the VUV ring at the National Synchrotron Light Source (NSLS) are ideally suited for high-efficiency ionization of atomic outer-shell electrons. Given the high fluxes of photons available on a wiggler beam line, multiple photoionization in an ion trap can be easily achieved within times short compared to typical ion storage times in the trap. Measurements of the time evolution of ion populations in such a trap can yield ionic photoionization cross sections and charge-exchange interaction rates for ion-atom or ion-ion collisions. The various processes governing this time evolution are discussed and model calculations illustrating the relative importance of these processes under different conditions are presented. 8 refs., 5 figs., 1 tab.
Date: September 1, 1987
Creator: Meron, M.; Johnson, B.M.; Jones, K.W. & Church, D.A.
Partner: UNT Libraries Government Documents Department

Search for promethium-like gold lines and other transitions of interest to fusion research

Description: EUV spectra in the range lambda = 13 to 40 rm were measured for foil-excited gold ions at 31 to 238 MeV. Data was recorded at the higher energies to extend and to complement previous measurements and at the lowest energy to see if the recently predicted 5s - 5p resonance lines in the Pm-like ion, Au XIX, could be seen in beam-foil excitation. The experimental results are presented, previous beam-foil measurements are reviewed, and the contributions and relations to fusion research are discussed.
Date: January 1, 1981
Creator: Johnson, B.M.; Jones, K.W.; Kruse, T.H.; Curtis, L.J. & Ellis, D.G.
Partner: UNT Libraries Government Documents Department

Investigations of molecular orbitals with accel-decel beams

Description: Quasimolecular transition energies can be found directly from the impact-parameter dependence of interference structure observed in measured K x-ray spectra. As these experiments require a K-vacancy bearing projectile at collision velocities small compared to the equivalent K-shell electron velocity, the accel-decel technique has to be used. Such an experiment was performed at the BNL Tandem Accel-Decel Facility for collisions of Cl/sup 16 +/ with Ar at energies ranging from 2.5 to 20 MeV. A new method of analysis using the uniform asymptotic approximation is described here. Quasimolecular transition energies derived using this method are compared to results of a previous analysis based on the determination of the relative positions of maxima and minima in the interference patterns. 6 references, 3 figures.
Date: September 1, 1984
Creator: Meron, M.; Johnson, B.M.; Jones, K.W.; Schuch, R.; Schmidt-Boecking, H. & Tserruya, I.
Partner: UNT Libraries Government Documents Department

X-ray spectra from the Cornell Electron-Beam Ion Source (CEBIS I)

Description: Radiation emitted from the Cornell electron beam ion source (CEBIS I) has been surveyed with a Si(Li) x-ray detector. These spectra can be used to estimate backgrounds from electron bremsstrahlung and to evaluate the feasibility of atomic physics experiments using the CEBIS I source in this configuration. 1 ref., 2 figs.
Date: January 1, 1985
Creator: Johnson, B.M.; Jones, K.W.; Kostroun, V.O.; Ghanbari, E. & Janson, S.W.
Partner: UNT Libraries Government Documents Department

APIPIS: the Atomic Physics Ion-Photon Interaction System

Description: A proposed new facility for the study of highly charged heavy ions is described. The basic elements of APIPIS, the Atomic Physics Ion-Photon Interaction System, are: (1) a source of multiply-charged ions; (2) a linear accelerator; (3) a synchrotron storage ring; and (4) a source of high brightness x rays. The placement of a heavy ion storage ring at the x-ray ring of the National Synchrotron Light Source will provide unique opportunities for the study of photo-excitation of heavy ions.
Date: January 1, 1985
Creator: Johnson, B.M.; Jones, K.W.; Meron, M. & Kostroun, V.O.
Partner: UNT Libraries Government Documents Department

Neutralization efficiency of plasma targets for high energy negative ions

Description: Plasma targets generated by hollow cathode discharges are used to neutralize a variety of multi-MeV negative ions as heavy as 28 a.m.u. Our plan is to determine the neutralization efficiency of hydrogen and argon plasma targets for D/sup -/, Li/sup -/, C/sup -/, O/sup -/, and Si/sup -/ at beam energiens of 2 to 8 MeV. The experiment is still in progress. Encouraging initial results are reported. 3 references, 4 figures, 1 table.
Date: January 1, 1983
Creator: Hershcovitch, A.I.; Johnson, B.M.; Kovarik, V.J.; Meron, M.; Jones, K.W. & Prelec, K.
Partner: UNT Libraries Government Documents Department

Science and technology needs: Integrated research and development, the path to gaining a defensible understanding on watch list'' tank risk and interim stabilization needs

Description: The watch list'' waste tanks at the Hanford Site in Washington state are those that the Secretary of the Department of Energy reports upon to the Congress because of the unresolved safety question. As such, they are subject to intense surveillance and an enhanced list of controls and safety procedures. The objective of the Waste Tank Safety Program is to mitigate the safety concerns with respect to these tanks, thereby removing them from the watch list.'' The essential step in this process is the development of a defensible position that reduce the risk of these tanks to an acceptable level. An integrated research and development (R D) program is believed to be the most cost-effective means of achieving the information required to mitigate the safety concern and to resolve the safety issues. This program uses chemical and physical modeling studies of synthetic waste, is substantiated with limited field data and radioactive samples from a tank, and uses numerical modeling to extrapolate results to actual tank-scale operations. 3 refs., 4 figs.
Date: September 1, 1991
Creator: Johnson, B.M.; Mellinger, G.; Strachan, D. & Hallen, R.
Partner: UNT Libraries Government Documents Department

Side extraction duoPIGatron-type ion source.

Description: We have designed and constructed a compact duoPIGatron-type ion source, for possible use in ion implanters, in such the ion can be extracted from side aperture in contrast to conventional duoPIGatron sources with axial ion extraction. The size of the side extraction aperture is 1x40 mm. The ion source was developed to study physical and technological aspects relevant to an industrial ion source. The side extraction duoPIGatron has stable arc, uniformly bright illumination, and dense plasma. The present work describes some of preliminary operating parameters of the ion source using Argon, BF3. The total unanalyzed beam currents are 23 mA using Ar at an arc current 5 A and 13 mA using BF3 gas at an arc current 6 A.
Date: August 26, 2007
Creator: GUSHENETS,V.I.; OKS, E.M.; HERSCHOVITCH, A. & JOHNSON, B.M.
Partner: UNT Libraries Government Documents Department

Results from E-Mevva and Z-Mevva: Development of new sources of intense high charge state heavy-ion beams

Description: The authors are exploring a new approach for heavy ion beam injection (e.g., into the Relativistic Heavy Ion Collider (RHIC) at BNL), as well as new sources of intense high charge state ions to be mounted on a relatively low voltage platform for high energy ion implantation. While conventional Metal Vapor Vacuum Arc (Mevva) ion sources can produce up to hundreds of milliamps or more of several-times-ionized metal ions (e.g., U3+), the recent results from Batalin et al. indicate that the addition of an energetic electron beam (E-Mevva) may lead to considerably higher charge states. An alternative way to produce the electron beam is Z-Mevva, in which a z-discharge plasma is used to enhance multiple ionization. As the vacuum arc plasma plume expands into a magnetized drift region, a z-discharge is triggered in the drifting metal plasma. The ions are then extracted and analyzed using a time-of-flight system. The authors report initial results using these schemes with applied discharge and electron beam voltages from 1 to 2 kV.
Date: November 1997
Creator: Hershcovitch, A.; Johnson, B. M.; Liu, F.; Anders, A. & Brown, I. G.
Partner: UNT Libraries Government Documents Department