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Title: Materials and technological processes for High-Gradient accelerating structures: new results from mechanical tests of an innovative braze-free cavity.

Abstract

Pure oxygen-free high-conductivity copper is a widely used material for manufacturing accelerating cavities working at room temperature. Several studies attempted to explain limitations associated with the maximum allowed field gradients and the behaviour of vacuum RF breakdown in copper accelerating structures through generation and movement of dislocations under stresses associated with RF electric and magnetic fields. Pure copper and also copper alloys undergo mechanical and thermal treatments to be hardened and strengthened during manufacturing, although their mechanical properties significantly change after heating above 590°C. High temperature brazing and diffusion bonding are assembly methods widely used to manufacture ultra-high vacuum accelerating devices. However, these processes, occurring at about 800–1000°C, significantly affect the mechanical properties of copper and copper alloys. We introduce here a novel Tungsten Inert Gas welding procedure, which is fast and keeps the high-gradient surfaces of the cavity and other components well below the copper annealing temperature. This process may be successfully used to manufacture copper-based accelerating components. This technology further preserves the hardness and cleanliness of copper in order to achieve the maximum accelerating gradient.

Authors:
 [1];  [2];  [3];  [4];  [5];  [6]
  1. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
  2. National Inst. of Nuclear Physics (INFN), Milan (Italy)
  3. High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)
  4. National Inst. of Nuclear Physics (INFN), Frascati (Italy); Rome International Centre for Materials Science Superstripes (RICMASS) (Italy)
  5. National Inst. of Nuclear Physics (INFN), Frascati (Italy)
  6. Comeb, Rome (Italy)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1617158
Grant/Contract Number:  
AC02-76SF00515
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Instrumentation
Additional Journal Information:
Journal Volume: 15; Journal Issue: 01; Journal ID: ISSN 1748-0221
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; Accelerator Applications; Accelerator Subsystems and Technologies

Citation Formats

Dolgashev, V. A., Faillace, L., Higashi, Y., Marcelli, A., Spataro, Bruno, and Bonifazi, R.. Materials and technological processes for High-Gradient accelerating structures: new results from mechanical tests of an innovative braze-free cavity.. United States: N. p., 2020. Web. https://doi.org/10.1088/1748-0221/15/01/p01029.
Dolgashev, V. A., Faillace, L., Higashi, Y., Marcelli, A., Spataro, Bruno, & Bonifazi, R.. Materials and technological processes for High-Gradient accelerating structures: new results from mechanical tests of an innovative braze-free cavity.. United States. https://doi.org/10.1088/1748-0221/15/01/p01029
Dolgashev, V. A., Faillace, L., Higashi, Y., Marcelli, A., Spataro, Bruno, and Bonifazi, R.. Mon . "Materials and technological processes for High-Gradient accelerating structures: new results from mechanical tests of an innovative braze-free cavity.". United States. https://doi.org/10.1088/1748-0221/15/01/p01029. https://www.osti.gov/servlets/purl/1617158.
@article{osti_1617158,
title = {Materials and technological processes for High-Gradient accelerating structures: new results from mechanical tests of an innovative braze-free cavity.},
author = {Dolgashev, V. A. and Faillace, L. and Higashi, Y. and Marcelli, A. and Spataro, Bruno and Bonifazi, R.},
abstractNote = {Pure oxygen-free high-conductivity copper is a widely used material for manufacturing accelerating cavities working at room temperature. Several studies attempted to explain limitations associated with the maximum allowed field gradients and the behaviour of vacuum RF breakdown in copper accelerating structures through generation and movement of dislocations under stresses associated with RF electric and magnetic fields. Pure copper and also copper alloys undergo mechanical and thermal treatments to be hardened and strengthened during manufacturing, although their mechanical properties significantly change after heating above 590°C. High temperature brazing and diffusion bonding are assembly methods widely used to manufacture ultra-high vacuum accelerating devices. However, these processes, occurring at about 800–1000°C, significantly affect the mechanical properties of copper and copper alloys. We introduce here a novel Tungsten Inert Gas welding procedure, which is fast and keeps the high-gradient surfaces of the cavity and other components well below the copper annealing temperature. This process may be successfully used to manufacture copper-based accelerating components. This technology further preserves the hardness and cleanliness of copper in order to achieve the maximum accelerating gradient.},
doi = {10.1088/1748-0221/15/01/p01029},
journal = {Journal of Instrumentation},
number = 01,
volume = 15,
place = {United States},
year = {2020},
month = {1}
}

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Works referenced in this record:

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