PAC07 - List of Authors (Bieniosek, F. M.)

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Bieniosek, F. M.

Paper	Title	Page
MOOBC02	Experiments in Warm Dense Matter using an Ion Beam Driver	140
	F. M. Bieniosek, M. Leitner, B. G. Logan, R. More, P. N. Ni, P. K. Roy LBNL, Berkeley, California J. J. Barnard, M. Kireeff Covo, A. W. Molvik LLNL, Livermore, California L. Grisham PPPL, Princeton, New Jersey H. Yoneda University of electro-communications, Tokyo
	Funding: Work performed under the auspices of the U. S. Dept. of Energy by LBNL, LLNL, and PPPL under Contracts No. W-7405-Eng-48, DE-AC02-05CH11231, and DE-AC02-76CH3073. We describe near term heavy-ion beam-driven warm dense matter (WDM) experiments. Initial experiments are at low beam velocity, below the Bragg peak, increasing toward the Bragg peak in subsequent versions of the accelerator. The WDM conditions are envisioned to be achieved by combined longitudinal and transverse neutralized drift compression to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. Initial candidate experiments include an experiment to study transient darkening in the WDM regime; and a thin target dE/dx experiment to study beam energy and charge state distribution in a heated target. Further experiments will explore target temperature and other properties such as electrical conductivity to investigate phase transitions and the critical point.
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TUXAB01	Absolute Measurement of Electron Cloud Density	754
	M. Kireeff Covo, R. H. Cohen, A. Friedman, A. W. Molvik LLNL, Livermore, California D. Baca, F. M. Bieniosek, B. G. Logan, P. A. Seidl, J.-L. Vay LBNL, Berkeley, California J. L. Vujic UCB, Berkeley, California
	Funding: This work was supported by the Director, Office of Science, Office of Fusion Energy Sciences, of the U. S. Department of Energy, LLNL and LBNL, under contracts No. W-7405-Eng-48 and DE-AC02-05CH11231. Beam interaction with background gas and walls produces ubiquitous clouds of stray electrons that frequently limit the performance of particle accelerator and storage rings. Counterintuitively we obtained the electron cloud accumulation by measuring the expelled ions that are originated from the beam-background gas interaction, rather than by measuring electrons that reach the walls. The kinetic ion energy measured with a retarding field analyzer (RFA) maps the depressed beam space-charge potential and provides the dynamic electron cloud density. Clearing electrode current measurements give the static electron cloud background that complements and corroborates with the RFA measurements, providing an absolute measurement of electron cloud density during a 5 us duration beam pulse in a drift region of the magnetic transport section of the High-Current Experiment (HCX) at LBNL.* * M. Kireeff Covo, A. W. Molvik, A. Friedman, J.-L. Vay, P. A. Seidl, G. Logan, D. Baca, and J. L. Vujic, Phys. Rev. Lett. 97, 054801 (2006).
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TUXC01	Status of DARHT 2nd Axis Accelerator at the Los Alamos National Laboratory	831
	R. D. Scarpetti, J. Barraza, C. Ekdahl, E. Jacquez, S. Nath, K. Nielsen, G. J. Seitz LANL, Los Alamos, New Mexico F. M. Bieniosek, B. G. Logan LBNL, Berkeley, California G. J. Caporaso, Y.-J. Chen LLNL, Livermore, California
	This presentation will provide a status report on the 2kA, 17MeV, 2-microsecond Dual-Axis Radiographic Hydrotest electron beam accelerator at Los Alamos National Laboratory, and will cover results from the cell refurbishment effort, commissioning experiments on beam transport and stability through the accelerator, and experiments exercising the beam chopper.
	Slides
WEOCC02	Overview of warm-dense-matter experiments with intense heavy ion beams at GSI-Darmstadt	2038
	P. N. Ni, F. M. Bieniosek, M. Leitner, B. G. Logan, R. More, P. K. Roy LBNL, Berkeley, California J. J. Barnard LLNL, Livermore, California A. Fernengel, A. Menzel TU Darmstadt, Darmstadt A. Fertman, A. Golubev, B. Y. Sharkov, I. Turtikov ITEP, Moscow D. Hoffmann, A. Hug, N. A. Tahir, A. Udrea, D. Varentsov GSI, Darmstadt M. Kulish, D. Nikolaev, A. Ternovoy IPCP, Chernogolovka, Moscow region
	Recently, a series of high energy density (HED) physics experiments with heavy ion beams have been carried out at the GSI heavy ion accelerator. The ion beam spot of heating uranium beam size of about 1 mm, pulse length about 120 ns and intensity 10⁹ particles/bunch. In these experiments, metallic solid and porous targets of macroscopic volumes were heated by intense heavy ion beams uniformly and quasi-isochorically, and temperature, pressure and expansion velocity were measured during the heating and cooling of the sample using a fast multi-channel radiation pyrometer, laser Doppler interferometer (VISAR), Michelson displacement interferometer and streak-camera-based-backlighting system. In the performed experiments target temperatures varying from 1'000 K to 12'000 K and pressure in kbar range were measured. Expansion velocities up to 2600 m/s have been registered for lead and up to 1700 m/s for tungsten targets.
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WEPMS024	Upgrades to the DAHRT Second Axix Induction Cells	2385
	K. Nielsen, J. Barraza, M. Kang LANL, Los Alamos, New Mexico F. M. Bieniosek, K. Chow, W. M. Fawley, E. Henestroza, L. R. Reginato, W. L. Waldron LBNL, Berkeley, California R. J. Briggs, B. A. Prichard SAIC, Los Alamos, New Mexico T. E. Genoni, T. P. Hughes Voss Scientific, Albuquerque, New Mexico
	The Dual-Axis Radiographic Hydrodynamics Test (DARHT) facility will employ two perpendicular electron Linear Induction Accelerators to produce intense, bremsstrahlung x-ray pulses for flash radiography. The second axis, DARHT II, features a 3-MeV injector and a 15-MeV, 2-kA, 1.6-microsecond accelerator consisting of 74 induction cells and drivers. Major induction cell components include high flux swing magnetic material (Metglas 2605SC) and a MycalexTM insulator. The cell drivers are pulse forming networks (PFNs). The DARHT II accelerator cells have undergone a series of test and modeling efforts to fully understand their operational parameters. Physical changes in the cell oil region, the cell vacuum region, and the cell drivers, together with different operational and maintenance procedures, have been implemented in the prototype. A series of prototype acceptance tests have demonstrated that the required cell lifetime is met at the increased performance levels. Shortcomings of the original design are summarized and improvements to the design, their resultant enhancement in performance, and various test results are discussed.
THPAS006	A Solenoid Final Focusing System with Plasma Neutralization for Target Heating Experiments	3519
	P. K. Roy, F. M. Bieniosek, J. E. Coleman, J.-Y. Jung, M. Leitner, B. G. Logan, P. A. Seidl, W. L. Waldron LBNL, Berkeley, California J. J. Barnard, A. W. Molvik LLNL, Livermore, California R. C. Davidson, P. Efthimion, E. P. Gilson, A. B. Sefkow PPPL, Princeton, New Jersey J. A. Duersch, D. Ogata UCB, Berkeley, California D. R. Welch Voss Scientific, Albuquerque, New Mexico
	Intense bunches of low-energy heavy ions have been suggested as means to heat targets to the warm dense matter regime (0.1 to 10 eV). In order to achieve the required intensity on target (~1 eV heating), a beam spot radius of approximately 0.5 mm, and pulse duration of 2 ns is required with an energy deposition of approximately 1 J/cm². This translates to a peak beam current of 8A for ~0.4 MeV K+ ions. To increase the beam intensity on target, a plasma-filled high-field solenoid is being studied as a means to reduce the beam spot size from several mm to the sub-mm range. We are building a prototype experiment to demonstrate the required beam dynamics. The magnetic field of the pulsed solenoid is 5 to 8 T. Challenges include suitable injection of the plasma into the solenoid so that the plasma density near the focus is sufficiently high to maintain space-charge neutralization of the ion beam pulse. Initial experimental results for a peak current of ~1A will be presented. This work was supported by the Office of Fusion Energy Sciences, of the U. S. Department of Energy under Contract No. DE-AC02-05CH11231, W-7405-Eng-48, DE-AC02-76CH3073 for HIFS-VNL.
FRYAB01	A Multi-beamlet Injector for Heavy Ion Fusion: Experiments and Modeling	3777
	G. A. Westenskow, D. P. Grote LLNL, Livermore, California F. M. Bieniosek, J. W. Kwan LBNL, Berkeley, California
	Funding: This work has been performed under the auspices of the US DOE by UC-LBNL under contract DE-AC03-76SF00098 and by UC-LLNL under contract W-7405-ENG-48. To provide a compact high-brightness heavy-ion beam source for Heavy Ion Fusion, we have performed experiments to study a proposed merging beamlet approach for the injector. We used an RF plasma source to produce the initial beamlets. An extraction current density of 100 mA/cm² was achieved, and the thermal temperature of the ions was below 1 eV. An array of converging beamlets was used to produce a beam with the envelope radius, convergence, and ellipticity matched to an electrostatic quadrupole 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.
	Slides
FRPMS018	1-MeV Electrostatic Ion Energy Analyzer	3940
	F. M. Bieniosek, M. Leitner LBNL, Berkeley, California
	Funding: Work performed under the auspices of the U. S. Department of Energy by the university of California, Lawrence Berkeley National Laboratory under Contract No. DE-AC03-76F00098. We describe a high resolution (a few x 10-4) 90-degree cylindrical electrostatic energy analyzer for 1-MeV (singly ionized) heavy ions for experiments in the Heavy Ion Fusion Science Virtual National Laboratory. By adding a stripping cell, the energy reach of the analyzer is extended to 2 MeV. This analyzer has high dispersion in a first-order focus with bipolar deflection-plate voltages in the range of ±50 kV. We will present 2- and 3-D calculations of vacuum-field beam trajectories, space-charge effects, field errors, and a multipole corrector. The corrector consists of 12 rods arranged in a circle around the beam. Such a corrector has excellent properties as an electrostatic quadrupole, sextupole, or linear combination. The improved energy diagnostic allows measurements of beam charge state and energy spread, such as caused by charge exchange or temperature anisotropy, and better understanding of experimental results in longitudinal beam studies.