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Title: Beam Pipe HOM Absorber for SRF Cavities

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Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Resource Relation:
Journal Name: Conf.Proc.C110328:1012-1014,2011; Conference: Particle Accelerator, 24th Conference (PAC'11) 28 Mar - 1 Apr 2011, New York, USA
Country of Publication:
United States

Citation Formats

Neubauer, M., Sah, R., Dudas, A., /MUONS Inc., Batavia, Hoffstaetter, G., Padamsee, H., Liepe, M., Shemelin, V., /Cornell U., Ko, K., Xiao, L., Ng, C., and /SLAC. Beam Pipe HOM Absorber for SRF Cavities. United States: N. p., 2016. Web.
Neubauer, M., Sah, R., Dudas, A., /MUONS Inc., Batavia, Hoffstaetter, G., Padamsee, H., Liepe, M., Shemelin, V., /Cornell U., Ko, K., Xiao, L., Ng, C., & /SLAC. Beam Pipe HOM Absorber for SRF Cavities. United States.
Neubauer, M., Sah, R., Dudas, A., /MUONS Inc., Batavia, Hoffstaetter, G., Padamsee, H., Liepe, M., Shemelin, V., /Cornell U., Ko, K., Xiao, L., Ng, C., and /SLAC. 2016. "Beam Pipe HOM Absorber for SRF Cavities". United States. doi:.
title = {Beam Pipe HOM Absorber for SRF Cavities},
author = {Neubauer, M. and Sah, R. and Dudas, A. and /MUONS Inc., Batavia and Hoffstaetter, G. and Padamsee, H. and Liepe, M. and Shemelin, V. and /Cornell U. and Ko, K. and Xiao, L. and Ng, C. and /SLAC},
abstractNote = {},
doi = {},
journal = {Conf.Proc.C110328:1012-1014,2011},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 7

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  • The development and testing of a prototype solar collector with several unique features is described. It is a concentrator that is capable of tracking the sun for several weeks without a position change because of a carefully designed acceptance angle. It is made of materials that in even low-volume mass production would make it highly competitive with flat plate collectors. Test results show all day efficiencies near 45% and peak efficiencies above 50%. The collector consists of a one-piece plastic envelope with an aluminized lower section that serves as the reflector. A light-weight frame engineered to provide minimum deflections holdsmore » the envelope in a unique shape. The absorber consists of several heat pipes in a cluster that is specially designed to achieve maximum thermal absorption with a reduction in effective emittance. The collector design offers the possibility of low-cost shipping and easy on-site assembly.« less
  • Heat pipes and vapour chambers work on heat exchange phenomena of two-phase flow and are widely used for in-dustrial and commercial applications. These devices offer very high effective thermal conductivities (5,000-200,000 W/m/K) and are adaptable to various sizes, shapes, and ori-entations. Although they have been found to be an excel-lent thermal management solution for laptops, satellites, and many things in-between, heat pipes and vapour cham-bers have yet to be adopted for use at particle accelerator facilities where they offer the possibility of more compact and more efficient means to remove heat from unwanted synchrotron radiation. As with all technologies, theremore » are inherent limitations. Foremost, they are limited by practi-cality to serve as local heat transfer devices; heat transfer over long distances is likely best provided by other means. Heat pipes also introduce unique failure modes which must be considered.« less
  • This joint project of Muons, Inc., Cornell University and SLAC was supported by a Phase I and Phase II grant monitored by the SBIR Office of Science of the DOE. Beam line HOM absorbers are a critical part of future linear colliders. The use of lossy materials at cryogenic temperatures has been incorporated in several systems. The design in beam pipes requires cylinders of lossy material mechanically confined in such a way as to absorb the microwave energy from the higher-order modes and remove the heat generated in the lossy material. Furthermore, the potential for charge build-up on the surfacemore » of the lossy material requires the conductivity of the material to remain consistent from room temperature to cryogenic temperatures. In this program a mechanical design was developed that solved several design constraints: a) fitting into the existing Cornell load vacuum component, b) allowing the use of different material compositions, c) a thermal design that relied upon the compression of the lossy ceramic material without adding stress. Coating experiments were performed that indicated the design constraints needed to fully implement this approach for solving the charge build-up problem inherent in using lossy ceramics. In addition, the ACE3P program, used to calculate the performance of lossy cylinders in beam pipes in general, was supported by this project. Code development and documentation to allow for the more wide spread use of the program was a direct result of this project was well.« less
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