Author: Grudiev, A.
Paper Title Page
TUPO023 Preserving Micron Tolerances Through the Assembly Process of an X-band Accelerating Structure 377
 
  • J. Sauza-Bedolla, N. Catalán Lasheras, A. Grudiev, S. Lebet, E. Rodriguez-Castro, P. Sobrino-Mompean, A. Solodko, K. T. Szypula
    CERN, Geneva, Switzerland
  • H. Bursali
    IZTECH, Izmir, Turkey
 
  The CLIC structures are designed for operating at X-Band, 2π/3 traveling wave mode with a loaded 100 MV/m gradient. Mechanical tolerances, at the submicron level, are required to satisfy the RF design constraints and beam dynamics and are reachable using ultra-precision diamond machining. However, inherent to the manufacturing process, there is a deviation from the nominal specifications and as a result; incorrect cavity dimensions produce a less efficient linac. Moreover, the assembly process increase the difference from the original geometry. As part of a cost and manufacturability optimization of the structures for mass production, this study aims to identify a correlation between frequency deviations and geometrical errors of the individual discs of the accelerating structures caused by the production process. A sensitivity analysis has been carried out to determine the most critical parameters. Cell frequency deviations have been monitored by bead pull measurements before and after bonding. Several accelerating structure prototypes have been tested to determine our assumptions and to assess if the assembly process preserves the tight tolerances achieved by machining.  
poster icon Poster TUPO023 [1.443 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO023  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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THPO018 Building a 12GHz Traveling Wave Accelerating Structure Brazed Through Irises 721
 
  • V.A. Dolgashev, G.B. Bowden, M. Dal Forno, A.A. Haase
    SLAC, Menlo Park, California, USA
  • A. Grudiev
    CERN, Geneva, Switzerland
  • H. Zha
    TUB, Beijing, People’s Republic of China
 
  Accelerating structures are usually manufactured by precision turning of individual cells combined with precision milling for complex parts such as rf power couplers. These multiple parts are staked and brazed into a complete structure. We consider an alternative approach: precision milling of multiple cells and couplers into metal blocks that comprise halves or quadrants of the complete structure. We successfully produced a 12~GHz Compact Linear Collider (CLIC) main linac accelerating structure prototype using this method. A previous prototype was designed as an open structure with a gap between cell irises. Here we describe a different approach, an accelerating structure which is brazed through irises. It is based on a multi-cell traveling wave structure designed at CERN for PSI, so called "T24 PSI 12 GHz". This brazed-through irises structure was built at SLAC for high power tests at CERN. Here we describe the details of this process.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO018  
About • paper received ※ 19 September 2018      issue date ※ 18 January 2019  
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THPO058 RF Design of a High-frequency RFQ Linac for PIXE Analysis 822
SPWR016   use link to see paper's listing under its alternate paper code  
THOP04   use link to see paper's listing under its alternate paper code  
 
  • H.W. Pommerenke, A. Bilton, A. Grudiev, A.M. Lombardi, S.J. Mathot, E. Montesinos, M.A. Timmins, M. Vretenar
    CERN, Geneva, Switzerland
  • H.W. Pommerenke, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
 
  Funding: This work has been sponsored by the Wolfgang Gentner Program of the German Federal Ministry of Education and Research (grant no. 05E12CHA).
Protons with an energy of few MeV are commonly used for Ion Beam Analysis of materials, in particular with the Proton Induced X-ray Emission technique (PIXE). Because of its non-damaging character, PIXE is used in a variety of fields, in particular for the diagnosis of cultural heritage artwork. A compact accelerator based on a high frequency RFQ (Radio Frequency Quadrupole) linac has been designed and is being built at CERN. The length of the RFQ is only one meter and it allows the acceleration of a proton beam up to an energy of 2 MeV. The complete system is conceived to be transportable, allowing PIXE analysis almost anywhere. This paper covers the RF design of the compact RFQ operating at 750 MHz. We present general accelerator parameters and the current state of the RF design, which includes RFQ geometry and coupler design, thermal simulation and first particle tracking results.
 
slides icon Slides THPO058 [2.404 MB]  
poster icon Poster THPO058 [2.192 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO058  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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THPO108 Development of an High Gradient Side Coupled Cavity for PROBE 924
THOP08   use link to see paper's listing under its alternate paper code  
 
  • S. Pitman, R. Apsimon, G. Burt
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • N. Catalán Lasheras, A. Grudiev, W. Wuensch
    CERN, Geneva, Switzerland
  • H.L. Owen
    UMAN, Manchester, United Kingdom
 
  The PROBE project aims to develop a high gradient proton accelerator for protons with energy around 250-350 MeV for proton radiography. Detailed studies have shown that the optimum design is a side coupled cavity at S-band. With an aperture of 8 mm a gradient of 54 MV/m can be obtained with 13 MW of RF power in a 30 cm structure. A prototype cavity has been machined by VDL and diffusion bonded by Bodycote. We present initial measurements of the prototype.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO108  
About • paper received ※ 17 September 2018      issue date ※ 18 January 2019  
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THPO109 A New Spherical Pulse Compressor Working with Degenerated "Whispering Gallery" Mode 928
SPWR023   use link to see paper's listing under its alternate paper code  
THOP09   use link to see paper's listing under its alternate paper code  
 
  • Z.B. Li, W. Fang, Q. Gu, Z.T. Zhao
    SINAP, Shanghai, People’s Republic of China
  • A. Grudiev
    CERN, Geneva, Switzerland
 
  CLIC is focusing on the Compact Linear Collider. To obtain a relatively high accelerating gradient, CLIC utilizes Pulse Compressors to increase the input power of accelerators. This work is to make an alternative design for CLIC pulse compression scheme. There are several kinds of pulse compressor: SLED, BOC, SLED-Ⅱ, spherical pulse compressor and so on. Usually, a spherical cavity, including BOC, can offer a higher Q factor compared with a cylindrical cavity. This design utilizes a spherical cavity working with degenerated Whispering Gallery mode.  
slides icon Slides THPO109 [1.738 MB]  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO109  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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