Keyword: DTL
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MOP237 Large Dynamic Range Beam Profile Measurements at SNS: Challenges and Achievements background, coupling, electron, linac 557
 
  • A.V. Aleksandrov, W. Blokland, A.P. Zhukov
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
Beam profile diagnostics with large dynamic range is an important tool for understanding origin and evolution of the beam halo in accelerators. Typical dynamic range for conventional wire scanners has been in the range of 100. In high power machines like SNS fractional losses of 1 to 100 part per million is of concern and, therefore, higher dynamic range of profile measurements is desirable. Our near term goal was set to achieve a dynamic range of at least 10000 for all profile measurements in the SNS linac and transport lines. We will discuss present status of this program, challenges, and solutions.
 
 
TUP012 Computer Simulations of Waveguide Window and Coupler Iris for Precision Matching coupling, linac, simulation, cavity 832
 
  • S.W. Lee
    ORNL RAD, Oak Ridge, Tennessee, USA
  • Y.W. Kang, K.R. Shin, A.V. Vassioutchenko
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
A tapered ridge waveguide iris input coupler and a waveguide ceramic disk windows are used on each of six drift tube linac (DTL) cavities in the Spallation Neutron Source (SNS). The coupler design employs rapidly tapered double ridge waveguide to reduce the cross section down to a smaller low impedance transmission line section that can couple to the DTL tank easily. The impedance matching is done by adjusting the dimensions of the thin slit aperture between the ridges that is the coupling element responsible for the power delivery to the cavity. Since the coupling is sensitive to the dimensional changes of the aperture, it requires careful tuning for precise matching. Accurate RF simulation using latest 3-D EM code is desirable to help the tuning for maintenance and spare manufacturing. Simulations are done for the complete system with the ceramic window and the coupling iris on the cavity to see mutual interaction between the components as a whole.
 
 
TUP134 New High Power Test Facility for VHF Power Amplifiers at LANSCE power-supply, controls, status, monitoring 1088
 
  • J.T.M. Lyles, S. Archuletta, J. Davis, L. Lopez, D. Rees, M.R. Rodriguez, G. M. Sandoval, Jr., A. Steck, D.J. Vigil
    LANL, Los Alamos, New Mexico, USA
  • D. Baca, R.E. Bratton, R.D. Summers
    Compa Industries, Inc., Los Alamos, New Mexico, USA
  • N.W. Brennan
    Texas A&M University, College Station, Texas, USA
 
  Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396
A new test facility was designed and constructed at Los Alamos Neutron Science Center (LANSCE) for testing the Thales TH628 Diacrode® and TH781 tetrode power amplifiers. Anode power requirements for the TH628 are 28 kV DC, with peak currents of 190 Amperes in long pulses. A new 225 uF capacitor bank supplies this demand. A charging power supply was obtained by re-configuring a 2 MW beam power supply remaining from another project. A traditional ignitron crowbar was designed to rapidly discharge the 88 kJ stored energy. The anode power supply was extensively tested using a pulsed tetrode switch and resistor load. A new Fast Protect and Monitor System (FPMS) was designed to take samples of RF reflected power, anode HV, and various tube currents, with outputs to quench the HV charging supply, remove RF drive and disable the conduction bias pulse to the grid of each tube during fault events. The entire test stand is controlled with a programmable logic controller, for normal startup sequencing and timing, protection against loss of cooling, and operator GUI.
 
 
TUP135 RF Design and Operating Results for a New 201.25 MHz RF Power Amplifier for LANSCE cathode, linac, coupling, cavity 1091
 
  • J.T.M. Lyles, N.K. Bultman, Z. Chen, J. Davis, A.C. Naranjo, D. Rees, G. M. Sandoval, Jr.
    LANL, Los Alamos, New Mexico, USA
  • D. Baca, R.E. Bratton, R.D. Summers
    Compa Industries, Inc., Los Alamos, New Mexico, USA
  • N.W. Brennan
    Texas A&M University, College Station, Texas, USA
 
  Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396
A prototype VHF RF Final Power Amplifier (FPA) for Los Alamos Neutron Science Center (LANSCE) has been designed, fabricated, and tested. The cavity amplifier met the design goals producing 3.2 MW peak and 480 kW of average power, at an elevation of 2.1 km. It was designed to use a Thales TH628 Diacrode®, a state-of-art tetrode power tube that is double-ended, providing roughly twice the power of a conventional tetrode. The amplifier is designed with tunable input and output transmission line cavity circuits, a grid decoupling circuit, an adjustable output coupler, TE mode suppressors, blocking, bypassing and decoupling capacitors, and a cooling system. The tube is connected in a full wavelength output circuit, with the lower main tuner situated ¾λ from the central electron beam region in the tube and the upper slave tuner ¼λ from the same point. We summarize the design processes and features of the FPA along with significant test results. A pair of production amplifiers are planned to be power-combined and installed at the LANSCE DTL to return operation to full beam duty factor.
 
 
WEP010 Design of the Bilbao Accelerator Low Energy Extraction Lines quadrupole, linac, dipole, neutron 1519
 
  • Z. Izaola, I. Rodríguez
    ESS-Bilbao, Zamudio, Spain
  • E. Abad, I. Bustinduy, R. Martinez, F. Sordo Balbin, D. de Cos
    ESS Bilbao, Bilbao, Spain
  • D.J. Adams, S.J.S. Jago
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • F.J. Bermejo
    Bilbao, Faculty of Science and Technology, Bilbao, Spain
  • V. Etxebarria, J. Portilla
    University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
 
  Funding: European Spallation Source - Bilbao
The ESS-Bilbao linac will accelerate H+ and H− beams up to 50 MeV, which need to be transported to three laboratories, where different types of experiments will be conducted. This paper reports on the preliminary design of the transfer line, which is mainly performed based on beam dynamics simulations.
 
 
WEP115 The FNAL Injector Upgrade rfq, extraction, quadrupole, linac 1701
 
  • C.-Y. Tan, D.S. Bollinger, K.L. Duel, J.R. Lackey, W. Pellico
    Fermilab, Batavia, USA
 
  The present FNAL linac H injector has been operational since the 1970s and consists of two magnetron H sources and a 750keV Cockcroft-Walton Accelerator. In the upgrade, both slit-type magnetron sources will be replaced with circular aperture sources, and the Cockcroft-Walton with a 200MHz RFQ. Operational experience at BNL (Brookhaven National Laboratory) has shown that the upgraded source and RFQ will be more reliable and require less manpower than the present system.  
 
THOCN4 High-Power Options for LANSCE linac, neutron, proton, klystron 2107
 
  • R.W. Garnett, E.J. Pitcher, D. Rees, L. Rybarcyk, T. Tajima
    LANL, Los Alamos, New Mexico, USA
 
  Funding: This work is supported by the U. S. Department of Energy Contract DE-AC52-06NA25396.
The LANSCE linear accelerator at Los Alamos National Laboratory has a long history of successful beam operations at 800 kW. We have recently studied options for restoration of high-power operations including schemes for increasing the performance to multi-MW levels. In this paper we will discuss the results of this study including the present limitations of the existing accelerating structures at LANSCE, and the high-voltage and RF systems that drive them. Several plausible options will be discussed and a preferred option will be presented that will enable the first in a new generation of scientific facilities for the materials community. The emphasis of this new facility is "Matter-Radiation Interactions in Extremes" (MaRIE) which will be used to discover and design the advanced materials needed to meet 21st century national security and energy security challenges.
 
slides icon Slides THOCN4 [2.903 MB]