Author: Catalan-Lasheras, N.     [Catalán Lasheras, N.]
Paper Title Page
TUPO022 Manufacturing of X-band Accelerating Structures: Metrology Analysis and Process Capability 374
 
  • J. Sauza-Bedolla, S. Atieh, N. Catalán Lasheras
    CERN, Geneva, Switzerland
 
  The fabrication tolerances of RF components are essential for CLIC X-band accelerating structures to perform efficiently. On one hand, the capability of high power accelerating structures depends on the shape accuracy and the asperity of the inner surfaces, when microwaves pass through the cavity. On the other hand, surface flatness and dimensional tolerances are necessary to guarantee a correct assembly process. Hence, the discs that build up the structure require sub-micrometre specifications and, in order to meet all the needs, ultra-precision machining using single crystal diamond tools is mandatory. This paper shows the analysis of the metrology results of the fabrication of 118 discs (4 accelerating structures). Dimensional and form tolerances are studied following the production order to find drifts in the production and to predict the impact on the assembly process. Finally, process capability is evaluated.  
poster icon Poster TUPO022 [2.987 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO022  
About • paper received ※ 10 September 2018      issue date ※ 18 January 2019  
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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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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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