Author: Doolittle, L.R.
Paper Title Page
TUOANO01
 Towards High Energy and Timing Stability in SCRF Linacs  
 
  • J.M. Byrd, L.R. Doolittle, G. Huang, M. Mellado, J.A.G. Olivieri, S. Paret, A. Ratti, C. Serrano
    LBNL, Berkeley, California, USA
  • C.H. Rivetta
    SLAC, Menlo Park, California, USA
  
  One of the concepts for the next generation of linac-driven FELs is a CW superconducting linac driving an electron beam with MHz repetition rates. One of the challenges for next generation FELs is improve the stability of the x-ray pulses by improving the shot-to-shot stability of the energy, charge, peak current, and timing jitter of the electron beam. A high repetition rate FEL with a CW linac presents an opportunity to use a variety of broadband feedbacks to stabilize the beam parameters. We present results on using this model to understand and predict the potential stability of such a machine. We also describe how we are implementing an SVD approach for broadband beam-based feedback to improve stability.  
slides icon Slides TUOANO01 [9.439 MB]  
 
TUOBNO03 An RF Deflecting Cavity Based Spreader System for Next Generation Light Sources 173
 
  • C. Sun, L.R. Doolittle, P. Emma, J.-Y. Jung, M. Placidi, A. Ratti
    LBNL, Berkeley, California, USA
  
  Lawrence Berkeley National Laboratory (LBNL) is developing design concepts for a multi-beamline (up to 10 lines) soft x-ray FEL array powered by a superconducting linear accelerator with a high bunch repetition rate of approximately one MHz. The FEL array requires a beam spreader system which can distribute individual electron bunches from the linac to each independently configurable beamline. We propose a new spreader system using RF deflecting cavities to deflect electron bunches as an alternative design to the fast kicker scheme. This RF approach offers more stable deflection amplitude while removing the limitations on the bunch repetition rate characteristic of the kicker approach. In this work, we describes the design concept of this RF based spreader system, including technical choices, design parameters and beamline optics.
[1] M. Placidi et al., Proceedings of IPAC2012, New Orleans, Louisiana, USA, pp.1765-1767 		 
slides icon Slides TUOBNO03 [1.391 MB]  
 
TUOCNO05 Design Concepts for a Next Generation Light Source at LBNL 193
 
  • J.N. Corlett, A.P. Allezy, D. Arbelaez, K.M. Baptiste, J.M. Byrd, C.S. Daniels, S. De Santis, W.W. Delp, P. Denes, R.J. Donahue, L.R. Doolittle, P. Emma, D. Filippetto, J.G. Floyd, J.P. Harkins, G. Huang, J.-Y. Jung, D. Li, T.P. Lou, T.H. Luo, G. Marcus, M.T. Monroy, H. Nishimura, H.A. Padmore, C. F. Papadopoulos, G.C. Pappas, S. Paret, G. Penn, M. Placidi, S. Prestemon, D. Prosnitz, H.J. Qian, J. Qiang, A. Ratti, M.W. Reinsch, D. Robin, F. Sannibale, R.W. Schoenlein, C. Serrano, J.W. Staples, C. Steier, C. Sun, M. Venturini, W.L. Waldron, W. Wan, T. Warwick, R.P. Wells, R.B. Wilcox, S. Zimmermann, M.S. Zolotorev
    LBNL, Berkeley, California, USA
  • C. Adolphsen, K.L.F. Bane, Y. Ding, Z. Huang, C.D. Nantista, C.-K. Ng, H.-D. Nuhn, C.H. Rivetta, G.V. Stupakov
    SLAC, Menlo Park, California, USA
  • D. Arenius, G. Neil, T. Powers, J.P. Preble
    JLAB, Newport News, Virginia, USA
  • C.M. Ginsburg, R.D. Kephart, A.L. Klebaner, T.J. Peterson, A.I. Sukhanov
    Fermilab, Batavia, USA
  
  Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
The NGLS collaboration is developing design concepts for a multi-beamline soft x-ray FEL array powered by a superconducting linear accelerator, operating with a high bunch repetition rate of approximately 1 MHz. The CW superconducting linear accelerator design is based on developments of TESLA and ILC technology, and is supplied by an injector based on a high-brightness, high-repetition-rate photocathode electron gun. Electron bunches from the linac are distributed by RF deflecting cavities to the array of independently configurable FEL beamlines with nominal bunch rates of ~100 kHz in each FEL, with uniform pulse spacing, and some FELs capable of operating at the full linac bunch rate. Individual FELs may be configured for different modes of operation, including self-seeded and external-laser-seeded, and each may produce high peak and average brightness x-rays with a flexible pulse format, and with pulse durations ranging from femtoseconds and shorter, to hundreds of femtoseconds. In this paper we describe current design concepts, and progress in R&D activities. 		 
slides icon Slides TUOCNO05 [5.982 MB]  
 
TUPSO12 RF Design Approach for an NGLS Linac 226
 
  • A. Ratti, J.M. Byrd, J.N. Corlett, L.R. Doolittle, P. Emma, M. Venturini, R.P. Wells
    LBNL, Berkeley, California, USA
  • C. Adolphsen, C.D. Nantista
    SLAC, Menlo Park, California, USA
  • D. Arenius, S.V. Benson, D. Douglas, A. Hutton, G. Neil, W. Oren, G.P. Williams
    JLAB, Newport News, Virginia, USA
  • C.M. Ginsburg, R.D. Kephart, T.J. Peterson, A.I. Sukhanov
    Fermilab, Batavia, USA
  
  Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
The Next Generation Light Source (NGLS) is a design concept for a multibeamline soft x-ray FEL array powered by a ~2.4 GeV CW superconducting linear accelerator, operating with a 1 MHz bunch repetition rate. This paper describes the concepts for the cavity and cryostat design operating at 1.3 GHZ and based on minimal modifications to the design of ILC cryomodules, This leverages the extensive experience derived from R&D that resulted in the ILC design. Due to the different nature of the two applications, particular attention is given now to high loaded Q operation and microphonics control, as well as high reliability and expected up time. The work describes the design and configuration of the linac, including choice of gradient, possible modes of operation, cavity design and RF power, as well as the consequent requirements for the cryogenic system. 		 
 
TUPSO13 Superconducting Linac Design Concepts for a Next Generation Light Source at LBNL 229
 
  • J.N. Corlett, J.M. Byrd, L.R. Doolittle, P. Emma, A. Ratti, F. Sannibale, M. Venturini, R.P. Wells, S. Zimmermann
    LBNL, Berkeley, California, USA
  • C. Adolphsen, C.D. Nantista
    SLAC, Menlo Park, California, USA
  • D. Arenius, G. Neil, T. Powers, J.P. Preble
    JLAB, Newport News, Virginia, USA
  • C.M. Ginsburg, R.D. Kephart, A.L. Klebaner, T.J. Peterson, A.I. Sukhanov
    Fermilab, Batavia, USA
  
  Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
The NGLS collaboration is developing design concepts for a multi-beamline soft X-ray FEL array powered by a superconducting linear accelerator, operating in CW mode, with a high bunch repetition rate of approximately 1 MHz. The superconducting linear accelerator design concept is based on existing TESLA and ILC technology, developed for this CW application in a light source. In this paper we describe design options and preferred approaches for the NGLS SRF linac components, cryomodules, and cryosystems. 		 
 
TUPSO19 The Photocathode Laser System for the APEX High Repetition Rate Photoinjector 255
 
  • D. Filippetto, L.R. Doolittle, G. Huang, G. Marcus, H.J. Qian, F. Sannibale
    LBNL, Berkeley, California, USA
  
  Funding: DOE grants No. DE-AC02-05CH11231.
The APEX injector has been built and commissioned at LBNL. A CW-RF Gun accelerates electron bunches to up 750 keV at MHz repetition rate. Different high efficiency photocathodes with different work functions are being tested with the help of a load lock system. The photocathode drive laser is thus conceived to provide up to 40 nJ per pulse in the UV and 200 nJ per pulse in the green at 1 MHz, with transverse and longitudinal shaping (flat top, up to 60 ps) for electron beam creation. A transfer line of about 15 meters has been designed and optimized for minimal jitters. Remote control of repetition rate, energy and position have been implemented on the system, together with offline and online diagnostic for beam monitoring. Here we present the laser system setup as well as the first measurements on longitudinal pulse shaping and jitter characterization.