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Title: A Reduced Gradient Output Design for SLAC's XL4 X-Band Klystron

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1146446
Report Number(s):
SLAC-PUB-16044
DOE Contract Number:
AC02-76SF00515
Resource Type:
Conference
Resource Relation:
Journal Name: Conf.Proc.C110904:412-414,2011; Conference: Presented at the 2nd International Particle Accelerator Conference (IPAC-2011), San Sebastian, Spain, 4-9 Sep 2011
Country of Publication:
United States
Language:
English
Subject:
Accelerators,ACCSYS

Citation Formats

Jensen, Aaron, Adolphsen, Chris, Candel, Arno, Fazio, Michael, Haase, Andy, Jongewaard, Erik, Sprehn, Daryl, Vlieks, Arnold, Wang, Faya, and /SLAC. A Reduced Gradient Output Design for SLAC's XL4 X-Band Klystron. United States: N. p., 2014. Web.
Jensen, Aaron, Adolphsen, Chris, Candel, Arno, Fazio, Michael, Haase, Andy, Jongewaard, Erik, Sprehn, Daryl, Vlieks, Arnold, Wang, Faya, & /SLAC. A Reduced Gradient Output Design for SLAC's XL4 X-Band Klystron. United States.
Jensen, Aaron, Adolphsen, Chris, Candel, Arno, Fazio, Michael, Haase, Andy, Jongewaard, Erik, Sprehn, Daryl, Vlieks, Arnold, Wang, Faya, and /SLAC. Tue . "A Reduced Gradient Output Design for SLAC's XL4 X-Band Klystron". United States. doi:. https://www.osti.gov/servlets/purl/1146446.
@article{osti_1146446,
title = {A Reduced Gradient Output Design for SLAC's XL4 X-Band Klystron},
author = {Jensen, Aaron and Adolphsen, Chris and Candel, Arno and Fazio, Michael and Haase, Andy and Jongewaard, Erik and Sprehn, Daryl and Vlieks, Arnold and Wang, Faya and /SLAC},
abstractNote = {},
doi = {},
journal = {Conf.Proc.C110904:412-414,2011},
number = ,
volume = ,
place = {United States},
year = {Tue Jul 22 00:00:00 EDT 2014},
month = {Tue Jul 22 00:00:00 EDT 2014}
}

Conference:
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  • A high-power X-band klystron employing a double-gap output cavity has been operating at SLAC. Multi-gap output circuits have lower surface gradients at the interaction gaps than single-gap ones but are prone to self-oscillate due to negative loading and trapped higher-order modes. In the double-gap circuit design, considerable attention had been directed to deal with these stability problems. The performance of the present tube appears to be limited by gap breakdown and beam interception particularly at long pulses. A three-gap output cavity is currently under development to further reduce the gap surface gradient. Another new feature of the circuit is anmore » enlarged downstream drift tube to improve on beam clearance. This paper discusses the considerations involved in designing a multi-gap output cavity and presents the cold test measurements on the three-gap circuit. The experimental data is compared with numerical results from the 3-D simulation code ARGUS.« less
  • We have developed algorithms for designing disk-loaded travelling-wave output structures for X-band klystrons to be used in the SLAC NLC. We use either a four- or five-cell structure in a {pi}/2 mode. The disk radii are tapered to produce an approximately constant gradient. The matching calculation is not performed on the tapered structure, but rather on a coupler whose input and output cells are the same as the final cell of the tapered structure, and whose interior cells are the same as the penultimate cell in the tapered structure. 2-D calculations using CONDOR model the waveguide as a radial transmissionmore » line of adjustable impedance. 3-D calculations with MAFIA model the actual rectangular waveguide and coupling slot. A good match is obtained by adjusting the impedance of the final cell. In 3D, this requires varying both the radius of the cell and the width of the aperture. When the output cell with the best match is inserted in the tapered structure, we obtain excellent cold-test agreement between the 2-D and 3-D models. We use hot-test simulations with CONDOR to design a structure with maximum efficiency and minimum surface fields. We have designed circuits at 11.424 GHz for different perveances. At 440 kV, microperveance 1.2, we calculated 81 MW, 53 percent efficiency, with peak surface field 76 MV/m. A microperveance 0.6 design was done using a ppM stack for focusing. At 470 kV, 193 amps, we calculated 58.7 MW, 64.7 percent efficiency, peak surface field 62.3 MV/m. At 500 kV, 212 amps, we calculated 67.1 MW, 63.3 percent efficiency, peak surface field 66.0 MV/m.« less
  • A high-power X-band klystron employing a double-gap output cavity has been operating at SLAC. Multi-gap output circuits have lower surface gradients at the interaction gaps than single-gap ones but are prone to self-oscillate due to negative loading and trapped higher-order modes. In the double-gap circuit design, considerable attention had been directed to deal with these stability problems. The performance of the present tube appears to be limited by gap breakdown and beam interception particularly at long pulses. A three-gap output cavity is currently under development to further reduce the gap surface gradient. Another new feature of the circuit is anmore » enlarged downstream drift tube to improve on beam clearance. This paper discusses the considerations involved in designing a multi-gap output cavity and presents the cold test measurements on the three-gap circuit. The experimental data is compared with numerical results from the 3-D simulation code ARGUS.« less
  • This paper describes the design and performance of the XL-1 klystron; a 50 MW klystron operating at a frequency of 11.424 GHz for use on the SLAC Next Linear Collider Test Accelerator (NLCTA). Problems associated with the development of high-power rf sources for NLC, and the solutions implemented on XL-1 are discussed.
  • Progress on the development of a 5MW 16 beam x-band multi-beam klystron is presented. The power from each of the 16 klystrons is combined using a matched waveguide network. Mechanical and electric models and simulations are discussed. The status of procuring and assembling parts is presented.