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ERL

  
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MOZBPA02 A Review of ERL Prototype Experience and Light Source Design Challenges FEL, linac, gun, superconducting-RF 39
 
  • S.L. Smith
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  The presentation will review the status of commissioning of ERL light source prototype projects drawing on experience from the JLab IR FEL, UK's ERL prototype ring and the Cornell injector project. State of the art design for future light source based on ERLs and FELs will be illustrated using the concept for the UK's 4GLS project.  
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MOPCH038 Predicted Parameters of the Second Stage of High Power Novosibirsk FEL FEL, undulator, electron, simulation 124
 
  • A.V. Kuzmin, O.A. Shevchenko, N. Vinokurov
    BINP SB RAS, Novosibirsk
  The first stage of Novosibirsk high power terahertz FEL was successfully put into operation in 2003*. The measured parameters of the FEL turned out to be in a good agreement with calculations [2]. The second and the third stages of the FEL are under construction now. The beam energy at the second stage will be about 20 MeV and the wavelength will change in the range 40-80 μm. In this paper we present the design parameters for the second stage FEL. The simulations were carried out with the help of 1-D code based on macroparticles. This code was previously used for the first stage simulations**.

*E. A. Antokhin et al. NIM A528 (2004) p.15-18.**A. V. Kuzmin et al. NIM A543 (2005) p.114-117.

 
 
MOPCH072 Adjustable Input Coupler Development for Superconducting Accelerating Cavity simulation, cryogenics, linac, electromagnetic-fields 193
 
  • M.V. Lalayan, M.A. Gusarova, V.I. Kaminsky, A.A. Krasnov, V.A. Makarov, N.P. Sobenin
    MEPhI, Moscow
  • A.A. Zavadtsev, D.A. Zavadtsev
    Introscan, Moscow
  The waveguide and coaxial-type input couplers for Energy Recovery Linac type injector cavity electrodynamical and thermal simulation results are presented. The devices are designed to feed the superconducting cavity with up to 500 kW RF power in continuous wave regime at 1.3 GHz operating frequency. The cavity external quality factor adjustment is provided. The heat load to the cryogenic system was lowered to a tolerable level by coupler design optimization.  
 
MOPCH073 A Project of a High-power FEL Driven by an SC ERL at KAERI FEL, sextupole, emittance, dipole 196
 
  • A.V. Bondarenko, S.V. Miginsky
    BINP SB RAS, Novosibirsk
  • Y.H. Han, Y.U. Jeong, B.C. Lee, S. H. Park
    KAERI, Daejon
  A project of a high-power FEL at Korea Atomic Energy Research Institute is described. The FEL is driven by a superconducting energy recovery linac. The future ERL will be connected to the existing machine without any modification. It consists of two 180-degree bents and two straight sections: one is for the FEL, another for a Compton X-rays source. One can choose the regime controlling the lenses. The total ERL is isochronous to avoid any problems with longitudinal beam instability. The total relative emittance degradation through the whole machine is ? 1.5. The FEL will be based on a 2 m helical in-vacuum undulator made of permanent magnets. One mirror of the optical cavity is blind and made of copper; the other one, the outcoupler, is semi-transparent and made of CVD diamond. The expected average power is a few kW and the tuning range 35…70 ?m.  
 
MOPCH161 Development of a Prototype Superconducting CW Cavity and Cryomodule for Energy Recovery TESLA, linac, TTF, ERLP 436
 
  • P.A. McIntosh, C.D. Beard, D.M. Dykes, B. Todd
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • S.A. Belomestnykh
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • A. Buechner, P. Michel, J. Teichert
    FZR, Dresden
  • J.M. Byrd, J.N. Corlett, D. Li
    LBNL, Berkeley, California
  • T. Kimura, T.I. Smith
    Stanford University, Stanford, Califormia
  • M. Liepe, V. Medjidzade, H. Padamsee, J. Sears, V.D. Shemelin
    Cornell University, Ithaca, New York
  • D. Proch
    DESY, Hamburg
  Energy Recovery LINAC (ERL) and LINAC-driven FEL proposals and developments are now widespread around the world. Superconducting RF (SRF) cavity advances made over the last 10 years for TESLA/TTF at 1.3 GHz, in reliably achieving accelerating gradients >20 MV/m, suggest their suitability for these ERL and FEL accelerators. Typically however, photon fluxes are maximised from the associated insertion devices when the electron bunch repetition rate is as high as possible, making CW-mode operation at high average current a fundamental requirement for these light sources. Challenges arise in controlling the substantial HOM power and in minimizing the power dissipated at cryogenic temperatures during acceleration and energy recovery, requiring novel techniques to be employed. This paper details a collaborative development for an advanced high-Qo cavity and cryomodule system, based on a modified TESLA cavity, housed in a Stanford/Rossendorf cryomodule. The cavity incorporates a Cornell developed resistive-wall HOM damping scheme, capable of providing the improved level of HOM damping and reduced thermal load required.  
 
MOPCH162 RF Requirements for the 4GLS Linac Systems linac, acceleration, electron, controls 439
 
  • P.A. McIntosh, C.D. Beard, D.M. Dykes, A.J. Moss
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  The 4GLS facility at Daresbury will combine energy recovery linac (ERL) and free electron laser (FEL) technologies to deliver a suite of naturally synchronised state-of-the-art sources of synchrotron radiation and FEL radiation covering the terahertz (THz) to soft X-ray regimes. CW-mode operation at high acceleration gradients are needed for the various 4GLS accelerator systems and here is where Superconducting Radio Frequency (SRF) cavities excel. Since resistive losses in the cavity walls increase as the square of the accelerating voltage, conventional copper cavities become uneconomical when the demand for high CW voltage grows with particle energy requirements. After accounting for the refrigeration power needed to provide the liquid helium operating temperature, a net power gain of several hundred remains for SRF over conventional copper cavities. This paper details the RF requirements for each of the SRF accelerating stages of the 4GLS facility, outlining techniques necessary to cope with CW-mode operation and HOM power generation.  
 
MOPCH175 High Power Testing RF System Components for the Cornell ERL Injector klystron, coupling, linac, factory 472
 
  • S.A. Belomestnykh, R.P.K. Kaplan, M. Liepe, P. Quigley, J.J.R. Reilly, C.K. Sinclair, V. Veshcherevich
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  There are two high power 1300 MHz RF systms under development for the Cornell University ERL Injector. The first system, based on a 16 kWCW IOT transmitter, will provide RF power to a buncher cavity. The second system employs five 120 kWCW klystrons to feed 2-cell superconducting cavities of the injector cryomodule. All components of these systems were ordered and some have already been delivered, including the IOT transmitter (manufactured by Thales-BM), 20 kWCW AFT circulator, 170 kWCW circulators (Ferrite Co.) and two prototype input couplers for superconducting cavities. A special LN2 cryostat has been designed and built for testing/processing the input couplers. The results of the first high-power tests are presented.  
 
MOPCH177 Status of HOM Load for the Cornell ERL Injector linac, damping, emittance, electron 478
 
  • V.D. Shemelin, B. Gillett
    Cornell University, Ithaca, New York
  • P. Barnes, M. Liepe, V. Medjidzade, H. Padamsee, G.R. Roy, J. Sears
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  The HOM load for the injector of the Energy Recovery Linac at Cornell University is proposed to work at a temperature of 80 K. The anticipated absorbed power of the load is up to 200 W. Versions with inner diameter of 78 and 106 mm are under development. Two different kinds of ferrites and a lossy ceramic are chosen as RF absorbers for the load to cover a wide frequency range. Measurements of electromagnetic properties of absorbing materials have been performed in a frequency range from 1 to 40 GHz. The engineering design of the load is ready and technological issues of brazing the absorbing tiles and cooling have been solved. Brazing quality is controlled by IR thermograms. First warm measurements of a prototype load are expected this summer.  
 
TUZBPA01 The ERL High Energy Cooler for RHIC electron, RHIC, luminosity, emittance 940
 
  • I. Ben-Zvi
    BNL, Upton, Long Island, New York
  This talk will first briefly review high-energy electron cooling, including the recent results from Fermilab. The main empasis will be on describing the proposed electron-cooling device for RHIC, based on an Energy Recovery Linac. Finally, results from the prototype ERL will presented.  
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TUPCH177 Measurement of the Sorption Characteristics of NEG Coated Pipes: The Transmission Factor Method vacuum, CERN, LHC, background 1432
 
  • A. Bonucci, A. Conte, P. Manini, S. Raimondi
    SAES Getters S.p.A., Lainate
  ZrTiV Non Evaporable Getter (NEG) coatings of vacuum chambers have found application in the particle accelerators to lower the gas pressure, during the operative conditions. For that, the characterization of the actual pumping speed of the NEG coating is a key issue. It is carried out by means of the dynamic sorption method according to ASTM F798-82 standard, conducted "offline" on a sample (coupon), suitably positioned inside the chamber to be coated and recovered after the process. To evaluate in-situ the sorption characteristics of getter coated chambers, a different measurement technique (Trasmission Factor Method) is here described. It is based on the measurement of pressures ratio at the inlet and the outlet of a coated pipe, under a flow of test gas. A calibration curve permits to evaluate sticking probability of the coated surface from the pressure ratio. The use of reference samples to calibrate the method is quite difficult. A better approach is a modellistic one, finding the dependency of pressure ratio on the average sticking probability, the pipe length and the section geometry and dimensions. Preliminary experimental results will be shown.  
 
THPCH041 Alternate Cavity Designs to Reduce BBU BBU, recirculation, TESLA, dipole 2874
 
  • E. Wooldridge
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  An investigation was carried out on alternate cavity designs to decrease the effect of the higher order modes (HOMs) whilst maintaining the cavity accelerating gradient. The cavities were modelled in Microwave Studio and the number of cells per cavity and the number of cells per unit length were examined. HOM data from these models was used in beam break up (BBU) codes to calculate the threshold and the results are presented here. The cells of each cavity were slightly deformed alternately in the x and y planes so that the fundamental frequency of the cavity remained unperturbed, whilst minimising the HOM coupling between consecutive cells. Other patterns, such as alternating each deformed cell by several degrees, were also investigated. The data from these e-m models was also used in BBU calculations and their thresholds calculated.