J.Y. Jung

Beam dynamics of the Neutralized Drift Compression Experiment-II, a novel pulse-compressing ion accelerator

Intense beams of heavy ions are well suited for heating matter to regimes of emerging interest. A new facility, NDCX-II, will enable studies of warm dense matter at ∼1 eV and near-solid density, and of heavy-ion inertial fusion target physics relevant to electric power production. For these applications the beam must deposit its energy rapidly, before the target can expand significantly. To form such pulses, ion beams are temporally compressed in neutralizing plasma; current amplification factors of ∼50–100 are routinely obtained on the Neutralized Drift Compression Experiment (NDCX) at the Lawrence Berkeley National Laboratory. In the NDCX-II physics design, an initial non-neutralized compression renders the pulse short enough that existing high-voltage pulsed power can be employed. This compression is first halted and then reversed by the beam’s longitudinal space-charge field. Downstream induction cells provide acceleration and impose the head-to-tail velocity gradient that leads to the final neutraliz...

Ion-beam-driven warm dense matter experiments

Author(s): Bieniosek, F.M.; Ni, P.; Leitner, M.; Roy, P.; More, R.; Barnard, J.J.; Covo, M. Kireeff; Molvik, A.W.; Yoneda, H.

A solenoid final focusing system with plasma neutralization for target heating experiments

Intense bunches of low-energy heavy ions have been suggested as means to heat targets to the warm dense matter regime (Temperature ~ 0.1 to 10 eV, solid density ~1% to 100%). In order to achieve the required intensity on target, 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 8 A 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. A prototype experiment to demonstrate the required beam dynamics has been built at Lawrence Berkeley National Laboratory. The operating magnetic field of the pulsed solenoid is 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 are presented.

New chicane magnet design for insertion device straights at the Advanced Light Source

A chicane magnet incorporating counter-rotating permanent magnet pairs together with trim coils has been designed for use in the Advanced Light Source (ALS) straights in conjunction with two insertion devices. In particular, this design is being developed for use in the existing beam line (BL) 4 elliptically polarizing undulator (EPU) straight and in the BL11 EPU straight, currently under design and construction. The purpose of the chicane is to provide a fixed angular separation between two successive EPU photon fans, and to correct steering perturbations resulting from EPU polarization state changes. Polarization changes occur on the time scale of one second; associated steering corrections must be accomplished in less than a second. Hysteresis associated with conventional iron core electromagnets prevents fast steering correction to the required precision. This consideration motivated the iron-free design presented here.

Status of the top-off upgrade of the ALS

The advanced light source is currently being upgraded for top-off operation. This major facility upgrade will provide an improvement in brightness from soft X-ray undulators of about one order of magnitude and keep the ALS competitive with the newest intermediate energy light sources. Major components of the upgrade include making the booster synchrotron capable of full energy operation, radiation safety studies, improvements to interlocks and collimation systems, diagnostics upgrades as well as emittance improvements in the main storage ring. Most hardware necessary as part of the upgrade has been installed and commissioned. The radiation safety studies are making good progress and have passed a first outside peer review successfully.

R+ D Progress Towards a Diffraction Limited Upgrade of the ALS

Author(s): Steier, C; Anders, A; Byrd, J; Chow, K; Duarte, R; Jung, J; Luo, T; Nishimura, H; Oliver, T; Osborn, J; Padmore, H; Pappas, C; Robin, D; Sannibale, F; De Santis, S; Schlueter, R; Sun, C; Swenson, C; Venturini, M; Waldron, W; Wallen, E; Wan, W; Yang, Y | Abstract: Copyright

HEAVY ION FUSION SCIENCE VIRTUAL NATIONAL LABORATORY 3nd QUARTER 2009 MILESTONE REPORT: Upgrade plasma source configuration and carry out initial experiments. Characterize improvements in focal spot beam intensity

HIFAN 1757 HEAVY ION FUSION SCIENCE VIRTUAL NATIONAL LABORATORY, 3rd QUARTER 2009 MILESTONE REPORT, Upgrade plasma source configuration and carry out initial experiments. Characterize improvements in focal spot beam intensity by S. Lidia, A. Anders, F.M. Bieniosek, A. Faltens, W. Greenway, J.Y. Jung, T. Katayanagi, B.G. Logan, C.W. Lee, M. Leitner, P. Ni, A. Pekedis, M. J. Regis, P. K. Roy, P. A. Seidl, W. Waldron Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA J.J. Barnard, A. Friedman, D. Grote, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA M. Dorf, E. Gilson Princeton Plasma Physics Laboratory Accelerator Fusion Research Division Ernest Orlando Lawrence Berkeley National Laboratory University of California June 2009 This work was supported by the Director, Office of Science, Office of Fusion Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

Complete fabrication of target experimental chamber and implement initial target diagnostics to be used for the first target experiments in NDCX-1

The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) has completed the fabrication of a new experimental target chamber facility for future Warm Dense Matter (WDM) experiments, and implemented initial target diagnostics to be used for the first target experiments in NDCX-1. The target chamber has been installed on the NDCX-I beamline. This achievement provides to the HIFS-VNL unique and state-of-the-art experimental capabilities in preparation for the planned target heating experiments using intense heavy ion beams.

CIRCE: A Ring‐based Source of Coherent Synchrotron Radiation

We present the concepts for an electron storage ring dedicated to and optimized for the production of stable coherent synchrotron radiation (CSR) over the far‐infrared terahertz wavelength range from 200 μm to about one cm. CIRCE (Coherent InfraRed CEnter) will be a 66 m circumference ring located on top of the ALS booster synchrotron shielding tunnel and using the existing ALS injector. This location provides enough floor space for both the CIRCE ring, its required shielding, and numerous beamlines. We present the calculated CIRCE photon flux where a gain of 6 – 9 orders of magnitude is shown compared to existing far‐IR sources. Additionally, the particular design of the dipole vacuum chamber has been optimized to allow an excellent transmission of these far‐infrared wavelengths. We believe that the CIRCE source can be constructed for a modest cost.