BNL, Upton, Long Island, New York, USA
The RHIC Spin Flipper's five high-Q AC dipoles which are driven by a swept frequency waveform require precise control of phase and amplitude during the sweep. This control is achieved using FPGA based feedback controllers. Multiple feedback loops are used to control and dynamically tune the magnets. The current implementation and results will be presented.
BNL, Upton, Long Island, New York, USA
We report on a study of the behavior of a secondary emission chamber (SEC). We show the dependence of the SEC signal on the charge and velocity of the primary beam for beams of protons, and heavy ions including Helium, Neon, Chlorine and Iron. We fill the SEC with a selection of different gases including Hydrogen, Helium, Nitrogen, Argon, and air, studying the SEC response when it is acting as an ion chamber. We also investigate the behavior of the SEC at intermediate pressures between 10-8 torr and atmospheric pressure.
BNL, Upton, Long Island, New York, USA
A residual gas fluorescence beam profile monitor at the relativistic heavy ion collider (RHIC) has successfully recorded vertical beam sizes of Au-ion beams from 3.85 to 100 GeV/n during the 2010 beam runs. Although the fluorescence cross section of Au-ion is sufficiently large, the low residual gas in a typical vacuum chamber of <10-9 torr produces necessary weak fluorescence photons. However, with adequate CCD exposure time, the vertical beam profiles are captured to provide an independent measurement of the RHIC beam size and emittance. This beam diagnostic technique, utilizing the Au-ion beam induced fluorescence from residual gas where hydrogen is still the dominant constituent in nearly all vacuum system, represents a step towards the realization of a truly noninvasive beam monitor for high-energy particle beams.
LBNL, Berkeley, California, USA
Cornell University, Ithaca, New York, USA
We report on an alternative way to measure beam fluence at NDCX-I, which is necessary for numerical simulation and planning of warm-dense-matter (WDM) experiments. So far the NDCX-I beam fluence has been characterized using a fast Faraday cup, radiation from a scintillator and tungsten foil calorimeter techniques. The present beam intensity is sufficient to melt and partially evaporate a 150 nm thick gold foil. Thermal emission (function of temperature) of the gold foil in the visible spectrum was measured during beam irradiation. A distinct shelf in the thermal emission intensity was observed after 600 ns, indicating that the sample reached the melting temperature. Using known heat capacity and latent heat of melting, the beam flux fully determines the duration of the melting shelf and the moment it appears. Using this technique we estimate an average 260 kW/cm2 beam flux over 10μs, which is consistent with values provided by the other methods.
BNL, Upton, Long Island, New York, USA
Testing a single hardware unit of an accelerator control system often requires the setup of a graphical user interface. Developing a dedicated application for a specific hardware unit test could be time consuming and the application may become obsolete after the unit tests. This paper documents a methodology for quick design and setup of an interface focused on performing unit tests of accelerator equipment with minimum programming work. The method has three components. The first is a generic accelerator device object (ADO) manager which can be used to setup, store, and log testing controls parameters for any unit testing system. The second involves the design of a TAPE (Tool for Automated Procedure Execution) sequence file that specifies and implements all testing and control logic. The third is the design of a PET (parameter editing tool) page that provides the unit tester with all the necessary control parameters required for testing. This approach has been used for testing the horizontal plane of the Stochastic Cooling Motion Control System at RHIC.
BNL, Upton, Long Island, New York, USA
Power Supply checkout is a necessary, pre-beam, time-critical function. At odds are the desire to decrease the amount of time to perform the checkout while at the same time maximizing the number and types of checks that can be performed and analyzing the results quickly (in case any problems exist that must be addressed). Controls and Power Supply Group personnel have worked together to develop tools to accomplish these goals. Power Supply checkouts are now accomplished in a time-frame of hours rather than days, reducing the number of person-hours needed to accomplish the checkout and making the system available more quickly for beam development.
IMP, Lanzhou, People's Republic of China
BNL, Upton, Long Island, New York, USA
Heavy ion beams from one of the BNL Tandem Van de Graaff accelerators will be made available for radiobiology studies on cell cultures. Energy losses need to be minimized both in the vacuum window and in the air in order to achieve the ranges required for the cells to be studied. This is particularly challenging for ions heavier than iron. The design is presented of a 0.4” diameter Havar film window that will satisfy these requirements. Films as thin as 80μinches were successfully pressure tested. The final thickness to be used may be slightly larger to help in achieving pin hole free windows. We discuss design considerations and present pressure and vacuum test results as well as tests with heavy ion beams.
LLNL, Livermore, California, USA
LBNL, Berkeley, California, USA
PPPL, Princeton, New Jersey, USA
UMD, College Park, Maryland, USA
Intense heavy-ion beams have long been considered a promising driver option for inertial-fusion energy production. This paper briefly compares inertial confinement fusion (ICF) to the more-familiar magnetic- confinement approach and presents some advantages of using beams of heavy ions to drive ICF instead of lasers. Key design choices in heavy-ion fusion (HIF) facilities are discussed, particularly the type of accelerator. We then review experiments carried out at Lawrence Berkeley National Laboratory (LBNL) over the past thirty years to understand various aspects of HIF driver physics. A brief review follows of present HIF research in the US and abroad, focusing on a new facility, NDCX-II, being built at LBNL to study the physics of warm dense matter heated by ions, as well as aspects of HIF target physics. Future research directions are briefly summarized.
LBNL, Berkeley, California, USA
High charge-state heavy-ion beams are of interest and used for a number of accelerator applications. Some accelerators produce the beams downstream of the ion source by stripping bound electrons from the ions as they pass through a foil or gas. In other accelerator systems, ions of charge state >1 are produced directly in the ion source. Heavy-ion inertial fusion (HIF) would benefit from low-emittance, high current ion beams with charge state >1. For these accelerators, the desired dimensionless perveance upon extraction from the emitter is ~0.001, and the electrical current of the beam pulse is ~ 1 A. For accelerator applications where high charge state and very high current are desired, space charge effects might present unique challenges. For example, in a stripper, the separation of charge states might create significant nonlinear space-charge forces which would impact the beam brightness. We will report on the particle-in-cell simulation of the formation of such beams for HIF, and review the possible technical approaches.
UMD, College Park, Maryland, USA
We apply the Venturini-Reiser envelope-dispersion equations* to a continuous beam in a uniform focusing/bending lattice to study the combined effects of linear dispersion and space charge. Within this simple model we investigate the scaling of average dispersion and the effects on beam dimensions; we also introduce a generalization of the space-charge intensity parameter and apply it to the University of Maryland Electron Ring (UMER) and other machines. In addition, we present results of calculations to test the smooth approximation by solving the Venturini-Reiser original equations and also through simulations with the code ELEGANT.
*M. Venturini and M. Reiser, Phys. Rev. Lett. 81, 1, p. 96, 6 July 1998
ITEP, Moscow, Russia
Intense heavy ion beam is an efficient tool to generate high energy density states in macroscopic amounts of matter. As result it enables to study astrophysical processes in the laboratory under controlled and reproducible conditions. For advanced experiments in high energy density physics the cylindrical target irradiated by hollow cylindrical beam is required. A new method for RF rotation of the ion beam is applied for the formation of the required hollow beam. The RF system consisting of two four-cell H-mode cavities with a resonant frequency of 297 MHz was chosen. The layout of the suggested rotating system for hollow beam formation including focusing elements is presented. The particle dynamics simulation was carried out for expecting beam parameters at ITEP Terawatt Accumulator project (ITEP TWAC). The results of simulation is considered in this paper.
BNL, Upton, Long Island, New York, USA
Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka, Japan
Warm Dense Matter (WDM) is a growing rapidly science field, which is related to planetary science and inertial fusion. It is difficult to expect the behavior because the state with high density and low temperature is completely different from ideal condition. The well-defined WDM generation is required to understand it. Moderate energy ion beam (~ 0.3 MeV/u) slightly above Bragg peak is an advantageous method for WDM because of the uniform energy deposition. Direct Plasma Injection Scheme (DPIS) with a linear accelerator has a potential for the beam parameter. The design of linear accelerator for WDM is presented.
BINP SB RAS, Novosibirsk, Russia
BNL, Upton, Long Island, New York, USA
As part of the search for a phase transition or critical point on the QCD phase diagram, an energy scan including 5 different energy settings was performed during the 2010 RHIC heavy ion run. While the top beam energy for heavy ions is at 100 GeV/n and the lowest achieved energy setpoint was significantly below RHICs injection energy of approximately 10 GeV/n, we also provided beams for data taking in a medium energy range above injection energy and below top beam energy. This paper reviews RHIC experience and challenges for RHIC medium energy operations that produced full experimental data sets at beam energies of 31.2 GeV/n and 19.5 GeV/n.