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Schoessow, P.

Paper Title Page
MOPAS032 Advanced Accelerator Control and Instrumentation Modules based on FPGA 506
  • P. Messmer, V. H. Ranjbar, D. J. Wade-Stein
    Tech-X, Boulder, Colorado
  • J. G. Power
    ANL, Argonne, Illinois
  • P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  Funding: Work supported by U. S. DOE Office of Science, Office of High Energy Physics, under grant DE-FG02-06ER84486.

Field Programmable Gate Arrays (FPGAs) offer a powerful alternative to ASICs or general purpose processors in accelerator control applications. Software development for these devices can be awkward and time consuming, however, when using low level hardware design languages. To facilitate the use of FPGAs in control systems we are developing a library of software tools based on ImpulseC, a high level subset of the C language specifically designed for FPGA programming. Development and testing of the software will be performed on a Xilinx Virtex-4 FPGA demo board. We will present timing benchmarks for common control functions (PID feedback loops, FIR and Kalman filters) and present plans for the development of a controller for the Argonne Wakefield Accelerator high current photoinjector based on this work.

THPMS074 High Transformer Ratios in Collinear Wakefield Accelerators 3154
  • C.-J. Jing, A. Kanareykin, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  • M. E. Conde, W. Gai, J. G. Power, Z. M. Yusof
    ANL, Argonne, Illinois
  Funding: DOE SBIR Phase II, DE-FG02-02ER83418.

Based on our previous experiment that successfully demonstrated wakefield transformer ratio enhancement in a 13.625 GHz dielectric-loaded collinear wakefield accelerator using the ramped bunch train technique, we present here a redesigned experimental scheme for even higher enhancement of the efficiency of this accelerator. Design of a collinear wakefield device with a transformer ratio R>>2, is presented. Using a ramped bunch train (RBT) rather than a single drive bunch, the enhanced transformer ratio (ETR) technique is able to increase the transformer ratio R above the ordinary limit of 2. To match the wavelength of the fundamental mode of the wakefield with the bunch length (σz=2 mm) of the new Argonne Wakefield Accelerator (AWA) drive gun, where the experiment will be performed, a 26.625 GHz dielectric based accelerating structure is required. This transformer ratio enhancement technique based on our dielectric-loaded waveguide design will result in a compact, high efficiency accelerating structure for future wakefield accelerators.

THPMS077 Progress towards Development of a Diamond-Based Cylindrical Dielectric Accelerating Structure 3163
  • A. Kanareykin, C.-J. Jing, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  • M. E. Conde, W. Gai
    ANL, Argonne, Illinois
  • R. Gat
    Coating Technology Solution, Inc., Somerville
  Funding: This research is supported by the US Department of Energy

In this talk, we present our recent developments on a high gradient diamond-based cylindrical dielectric loaded accelerator (DLA). The final goal of this research is to achieve a record accelerating gradient (~ 600 MV/m) in a demonstration of the structure at high power and with accelerated beam. We discuss here a new technology for the development of cylindrical diamond-based waveguides and the design, fabrication and high power testing of a cylindrical diamond-based DLA accelerating structure. The electrical and mechanical properties of diamond make it an ideal candidate material for use in dielectric accelerators: high RF breakdown level, extremely low dielectric losses and the highest thermoconductive coefficient available. Multipacting of the CVD diamond can be suppressed by diamond surface dehydrogenation. A plasma supported Chemical Vapor Deposition (CVD) technology to produce low loss high quality cylindrical diamond layers is presented. Special attention is devoted to the numerical optimization of the coupling section, where the surface magnetic and electric fields are minimized relative to the accelerating gradient and within known metal surface breakdown limits.

THPMS078 Status of the Microwave PASER Experiment 3166
  • P. Schoessow, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • S. P. Antipov, M. E. Conde, W. Gai, J. G. Power
    ANL, Argonne, Illinois
  • E. Bagryanskaya
    International Tomography Center, SB RAS, Novosibirsk
  • V. Gorelik, A. Kovshik, A. V. Tyukhtin, N. Yevlampieva
    Saint-Petersburg State University, Saint-Petersburg
  • L. Schachter
    Technion, Haifa
  Funding: Work supported by US Department of Energy

The PASER is a new method for particle acceleration, in which energy from an active medium is transferred to a charged particle beam. The effect is similar to the action of a maser or laser with the stimulated emission of radiation being produced by the virtual photons in the electromagnetic field of the beam. We are developing a demonstration PASER device operating at X-band, based on the availability of a new class of active materials that exhibit photoinduced electron spin polarization. We will report on the status of active material development and measurements, numerical simulations, and preparations for microwave PASER experiments at the Argonne Wakefield Accelerator facility.

THPMS079 Nonlinear Permittivity Effects in Dielectric Accelerating Structures 3169
  • P. Schoessow, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • V. P. Yakovlev
    Omega-P, Inc., New Haven, Connecticut
  Funding: Work supported by the US Department of Energy

New low loss ferroelectric ceramic materials* possessing large variations in the permittivity as a function of the electric field present interesting and potentially useful applications for dielectric loaded accelerating structures, both wakefield-based and driven by an external rf source. We will consider X-band cylindrical dielectric structures and report numerical results on frequency multiplication, wave steepening and shock formation, and the effect of nonlinearities on the mode structure of these devices. We will examine applications of nonlinear dielectric devices to high gradient acceleration, rf sources, and beam diagnostics.

* ''Fast Switching Ferroelectric Materials for Accelerator Applications'', A. Kanareykin et al., Proceedings of Advanced Accelerator Concepts 2006 (in press)

FRPMN064 Applications of Cherenkov Radiation in Dispersive and Anisotropic Metamaterials to Beam Diagnostics 4156
  • A. V. Tyukhtin
    Saint-Petersburg State University, Saint-Petersburg
  • S. P. Antipov
    ANL, Argonne, Illinois
  • A. Kanareykin, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  Funding: US Department of Energy

Cherenkov radiation (CR) is extensively used for detection of charged particles. The prompt nature of the radiation is one major advantage for diagnostics that measure temporal properties of the beam. However, low signal levels and small angles of radiation with respect to the particle trajectory present limitations on the use of traditional detector media. Using modern artificial metamaterials as Cherenkov radiators can provide essential advantages. As a rule metamaterials are characterized by strong dispersion and anisotropy that can be engineered to the requirements of the detector. We present theoretical and numerical analyses of CR in bulk anisotropic and dispersive media and in waveguides. The properties exhibited by these materials (large angles of radiation, two maxima in the angular distributions, etc.) allow the design of detectors with unusual characteristics, like a detector that registers almost all moving particles, and simultaneously only particles with velocity exceeding a predetermined threshold. We consider the case of a material that is approximately equivalent to an isotropic left-handed medium that also presents advantages as a Cherenkov medium.

FRPMS094 Beam Breakup Instabilities in Dielectric Structures 4300
  • A. Kanareykin, C.-J. Jing, A. L. Kustov, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  • W. Gai, J. G. Power
    ANL, Argonne, Illinois
  Funding: This research is supported by the US Department of Energy

We report on the experimental and numerical investigation of beam breakup (BBU) effects in dielectric structures resulting from parasitic wakefields. The experimental program focuses on measurements of BBU in a number of wakefield devices: (a) a 26 GHz power extraction structure; (b) a high gradient dielectric wakefield accelerator; (c) a wakefield structure driven by a high current ramped bunch train for multibunch BBU studies. New beam diagnostics will provide methods for studying parasitic wakefields that are currently unavailable at the AWA facility. The numerical part of this research is based on a particle-Green's function based beam breakup code we are developing that allows rapid, efficient simulation of beam breakup effects in advanced linear accelerators. The goal of this work is to be able to compare the accurate numerical results obtained from the new BBU code with the results of the detailed experimental measurements. An external focusing system for the control of the beam in the presence of strong transverse wakefields is considered.