Litvinenko, V.N.
(Vladimir N. Litvinenko)

THBOC04 Ampere Average Current Photoinjector and Energy Recovery Linac
Ilan Ben-Zvi, A. Burrill, R. Calaga, P. Cameron, X. Chang, D. Gassner, H. Hahn, A. Hershcovitch, H.C. Hseuh, P. Johnson, D. Kayran, J. Kewisch, R. Lambiase, Vladimir N. Litvinenko, G. McIntyre, A. Nicoletti, J. Rank, T. Roser, J. Scaduto, K. Smith, T. Srinivasan-Rao, K.-C. Wu, A. Zaltsman, Y. Zhao (BNL, Upton, Long Island, New York), H. Bluem, A. Burger, Mike Cole, A. Favale, D. Holmes, John Rathke, Tom Schultheiss, A. Todd (AES, Medford, NY), J. Delayen, W. Funk, L. Phillips, Joe Preble (Jefferson Lab, Newport News, Virginia)

High-power Free-Electron Lasers were made possible by advances in superconducting linac operated in an energy-recovery mode, as demonstrated by the spectacular success of the Jefferson Laboratory IR-Demo. In order to get to much higher power levels, say a fraction of a megawatt average power, many technological barriers are yet to be broken. BNL’s Collider-Accelerator Department is pursuing some of these technologies for a different application, that of electron cooling of high-energy hadron beams. I will describe work on CW, high-current and high-brightness electron beams. This will include a description of a superconducting, laser-photocathode RF gun employing a new secondary-emission multiplying cathode and an accelerator cavity, both capable of producing of the order of one ampere average current.

WEBOS04 Potential Use of eRHIC’s ERL for FELs and Light Sources
Vladimir N. Litvinenko, Ilan Ben-Zvi (BNL, Upton, Long Island, New York)

One of the design of future electron-hadron collider eRHIC* is based on a 5-10 GeV high current energy-recovery linac (ERL) with possible extension of its energy to 20 GeV. This ERL will operate with high brightness electron beams, which do naturally match requirements for X-ray FELs and other next generation light sources. In this paper we present a number of possible scenarios which use eRHIC ERL in parasitic and dedicated mode for SASE, HGHG and oscillator X-ray FELs. We explore a possibility of optic-free X-ray oscillator in detail.

THPOS53 Novel Method for Phase-Space Tomography of Rapidly Evolving E-beams
Kevin Chalut (Duke University, Durham, North Carolina), Vladimir N. Litvinenko (BNL, Upton, Long Island, New York), Igor V. Pinayev (BNL/NSLS, Upton, Long Island, New York)

Traditional tomographic methods based on Radon transformation require a full set projections covering full 180-degrees. This technique is applicable only to a stationary distribution of electrons, which do not evolve. In addition, this method can’t work with incomplete sub-set of data such as a few projections covering total angle of few degrees. We present novel method of tomography working with a limited number of non-degenerated linear projections. We present the description of the method, discuss its advantages as well as limitations. We compare the method with the Radon transformation. We present the application of this method to the study the dynamics of e-beam in longitudinal phase space using dual sweep streak-camera with psec resolution. This method allowed us to restore the evolution of e-beam during a giant pulse in a storage ring FEL when the distribution of the electrons changes completely during one synchrotron oscillation. We discuss another possible applications of this method in advanced FEL systems, where effects of space charge, nonlinearities or coherent synchrotron radiation impair traditional diagnostics methods.

THPOS54 Characterization of Storage Ring FEL operating in the Giant Pulse Mode
Igor V. Pinayev, Kevin Chalut (Duke University, Durham, North Carolina), Vladimir N. Litvinenko (BNL, Upton, Long Island, New York)

In this paper we present the experimental results on the storage ring free electron laser operating in the giant pulse mode with variable repetition rate. The experiments were conducted in the wide range of the electron beam energies from 270 MeV to 600 MeV with the giant pulses generated using a gain modulator. Dependence of the peak and average power, and the other properties and parameters of giant pulses on the pulse repetition rate are studied. In particular, it is found that the average lasing power in the giant pulse mode reaches levels of 70-90% of that in the CW power mode. Applications of such mode of operation are discussed.

THPOS56 VISA IB: Ultra-High Bandwidth, High Gain SASE FEL
Gerard Andonian, Ronald Barkley Agustsson, Alex Murokh, Claudio Pellegrini, Sven Reiche, James B Rosenzweig, Gil Travish (UCLA, Los Angeles, California), Marcus Babzien, Ilan Ben-Zvi, Jung Yun Huang, Vladimir N. Litvinenko, Vitaly Yakimenko (BNL, Upton, Long Island, New York), Ilario Boscolo, S. Cialdi, Alessandro Flacco (INFN Milano, Milano), Massimo Ferrario, Luigi Palumbo, C. Vicario (INFN/LNF, Frascati (Roma))

The results of a high energy-spread SASE FEL experiment, the intermediary experiment linking the VISA I and VISA II projects, are presented. A highly chirped beam (~1.7%) was transported without correction of longitudinal aberrations in the ATF dogleg, and injected into the VISA undulator. The output FEL radiation displayed an uncharacteristicly large bandwidth (~11%) with extremely stable lasing and measured energy of about 2 microJoules. Start-to-end simulations reproduce key features of the measured results and provide an insight into the mechanisms giving rise to such a high bandwidth. These analyses are described as they relate to important considerations for the VISA II experiment.

TUPOS64 High Current Energy Recovery Linac at BNL
Vladimir N. Litvinenko, Donald Barton, D. Beavis, Ilan Ben-Zvi, Michael Blaskiewicz, J.M. Brennan, A. Burrill, R. Calaga, P. Cameron, X. Chang, Roger Connolly, D. Gassner, H. Hahn, A. Hershcovitch, H.C. Hseuh, P. Johnson, D. Kayran, J. Kewisch, R. Lambiase, G. McIntyre, W. Meng, T. C. Nehring, A. Nicoletti, D. Pate, J. Rank, T. Roser, T. Russo, J. Scaduto, K. Smith, T. Srinivasan-Rao, N. Williams, K.-C. Wu, Vitaly Yakimenko, K. Yip, A. Zaltsman, Y. Zhao (BNL, Upton, Long Island, New York), H. Bluem, A. Burger, Mike Cole, A. Favale, D. Holmes, John Rathke, Tom Schultheiss, A. Todd (AES, Medford, NY), J. Delayen, W. Funk, L. Phillips, Joe Preble (Jefferson Lab, Newport News, Virginia)

We present the design, the parameters of a small test Energy Recovery Linac (ERL) facility, which is under construction at Collider-Accelerator Department, BNL. This R&D facility has goals to demonstrate CW operation of ERL with average beam current in the range of 0.1 - 1 ampere, combined with very high efficiency of energy recovery. A possibility for future up-grade to a two-pass ERL is considered. The heart of the facility is a 5-cell 700 MHz super-conducting RF linac with HOM damping. Flexible lattice of ERL provides a test-bed for testing issues of transverse and longitudinal instabilities and diagnostics of intense CW e-beam. ERL is also perfectly suited for a far-IR FEL. We present the status and our plans for construction and commissioning of this facility.