IPAC2015 - List of Authors (De Silva, S.U.)

Paper	Title	Page
WEPWI039	Engineering Study of Crab Cavity HOM Couplers for LHC High Luminosity Upgrade	3578
	H. Park, S.U. De Silva, J.R. Delayen, R.G. Olave ODU, Norfolk, Virginia, USA T. Capelli CERN, Geneva, Switzerland S.U. De Silva, J.R. Delayen, H. Park JLab, Newport News, Virginia, USA Z. Li SLAC, Menlo Park, California, USA T.H. Nicol Fermilab, Batavia, Illinois, USA N. Templeton STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	The LHC is planning to employ crab cavities for the high luminosity upgrade. Old Dominion University and SLAC National Laboratory are developing the crab cavity completed with the HOM damping couplers. The HOM couplers are coaxial type and perform over broad band up to 2 GHz. The amount of extracted power requires active cooling using liquid helium. The electromagnetic study has provided expected power dissipation on the coupler. Correlations between the fabrication tolerance and its damping performance have been studied and the results are providing guidelines on how to manufacture the HOM couplers. This paper summarizes the engineering studies; mechanical strength as a part of pressure system, thermal stability, and fabrication method to ensure the required tolerance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI039
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WEPWI004	FPC and Hi-Pass Filter HOM Coupler Design for the RF Dipole Crab Cavity for the LHC HiLumi Upgrade	3492
	Z. Li SLAC, Menlo Park, California, USA S.U. De Silva, J.R. Delayen, R.G. Olave, H. Park ODU, Norfolk, Virginia, USA
	Funding: Work partially supported by the US DOE through the US LHC Accelerator Research Program (LARP), and by US DOE under contract number DE-AC02-76SF00515. A 400-MHz compact RF dipole (RFD) crab cavity design was jointly developed by Old Dominion University and SLAC under the support of US LARP program for the LHC HiLumi upgrade. The RFD cavity design is consisted of a rounded-square tank and two ridged deflecting poles, operating with a TE11-like dipole mode, which is the lowest mode of the cavity. A prototype RFD cavity is being manufactured and will be tested on the SPS beam line at CERN. The coaxial fundamental Power Coupler (FPC) of the prototype cavity was re-optimized to minimizing the power heating on the coupler internal antenna. A hi-pass filter HOM damping coupler was developed to achieve the required wakefield damping while maintaining a compact size to fit into the beam line space. In this paper, we will discuss the details of the RF optimization and tolerance analyses of the FPC and HOM couplers.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI004
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WEPWI035	Beam Dynamics Studies of 499 MHz Superconducting RF-Dipole Deflecting Cavity System	3564
	S.U. De Silva, K.E. Deitrick, J.R. Delayen, H. Park ODU, Norfolk, Virginia, USA
	A 499 MHz deflecting cavity has been designed as a three-way beam spreader to separate an electron beam into 3 beams. The rf tests carried out on the superconducting rf-dipole cavity have demonstrated that a transverse voltage of 4.2 MV can be achieved with a single cavity. This paper discusses the beam dynamics on a deflecting structure operating in continuous-wave mode with a relativistic beam. The study includes the analysis on emittance growth, energy spread, and change in bunch size including effects due to field non-uniformities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI035
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WEPWI036	Design and Prototyping of a 400 MHz RF-dipole Crabbing Cavity for the LHC High-Luminosity Upgrade	3568
	S.U. De Silva, J.R. Delayen, H. Park ODU, Norfolk, Virginia, USA Z. Li SLAC, Menlo Park, California, USA T.H. Nicol Fermilab, Batavia, Illinois, USA
	LHC High Luminosity Upgrade is in need of two crabbing systems that deflects the beam in both horizontal and vertical planes. The 400 MHz rf-dipole crabbing cavity system is capable of crabbing the proton beam in both planes. At present we are focusing our efforts on a complete crabbing system in the horizontal plane. Prior to LHC installation the crabbing system will be installed for beam test at SPS. The crabbing system consists of two rf-dipole cavities in the cryomodule. This paper discusses the electromagnetic design and mechanical properties of the rf-dipole crabbing system for SPS beam test.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI036
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WEPWI037	Imperfection and Tolerance Analysis of HOM Couplers for ODU/SLAC 400 MHz Crabbing Cavity	3572
	S.U. De Silva, J.R. Delayen, H. Park ODU, Norfolk, Virginia, USA Z. Li SLAC, Menlo Park, California, USA R.G. Olave Old Dominion University, Norfolk, Virginia, USA
	In preparation for the LHC High Luminosity upgrade, a 400 MHz crab cavity has been developed jointly at ODU/SLAC, including two higher order mode couplers designed to dampen the wakefields in order to comply with the impedance budget specified for the LHC system. During fabrication, assembly, and processing of the couplers, a number of imperfections may arise that could modify the higher order mode spectrum and the associated impedance for each mode. We present here a detailed study of the imperfections of the horizontal- and vertical- HOM couplers, and the associated allowed tolerances for manufacture, assembly and processing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI037
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THZMS1	A New Class of Superconducting Structures for the Deflection and Crabbing of Particle Beams
	S.U. De Silva ODU, Norfolk, Virginia, USA
	Recently, superconducting deflecting and crabbing cavities for particle accelerators and colliders have been an area of intense research. The future colliders pushing the energy and luminosity frontiers and particle accelerators with multi-experimental stations have expanded the need of deflecting/crabbing cavities. The current applications in need of such cavities operate at low frequencies and have also specifications with strict dimensional constraints, high operating transverse gradients, and tight impedance budgets. At low operating frequencies the use of standard cavities operating in TM110-like modes has been very challenging. A new type of superconducting deflecting/crabbing structure has been designed that has a wide range of applications. The new rf-dipole cavity operates in a TE11-like mode where several cavities have been fabricated, and tested. The rf performance shows that these structures are capable of operating at high transverse gradients and will be a very attractive deflecting/crabbing cavity for many current applications. At present, a 400 MHz rf-dipole crabbing cavity system is under development to be tested at SPS at LHC as part of the LHC High Luminosity Upgrade.
	Slides THZMS1 [1.861 MB]
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Paper

Title

Page

Engineering Study of Crab Cavity HOM Couplers for LHC High Luminosity Upgrade

3578

H. Park, S.U. De Silva, J.R. Delayen, R.G. Olave
ODU, Norfolk, Virginia, USA
T. Capelli
CERN, Geneva, Switzerland
S.U. De Silva, J.R. Delayen, H. Park
JLab, Newport News, Virginia, USA
Z. Li
SLAC, Menlo Park, California, USA
T.H. Nicol
Fermilab, Batavia, Illinois, USA
N. Templeton
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

The LHC is planning to employ crab cavities for the high luminosity upgrade. Old Dominion University and SLAC National Laboratory are developing the crab cavity completed with the HOM damping couplers. The HOM couplers are coaxial type and perform over broad band up to 2 GHz. The amount of extracted power requires active cooling using liquid helium. The electromagnetic study has provided expected power dissipation on the coupler. Correlations between the fabrication tolerance and its damping performance have been studied and the results are providing guidelines on how to manufacture the HOM couplers. This paper summarizes the engineering studies; mechanical strength as a part of pressure system, thermal stability, and fabrication method to ensure the required tolerance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWI004

FPC and Hi-Pass Filter HOM Coupler Design for the RF Dipole Crab Cavity for the LHC HiLumi Upgrade

3492

Z. Li
SLAC, Menlo Park, California, USA
S.U. De Silva, J.R. Delayen, R.G. Olave, H. Park
ODU, Norfolk, Virginia, USA

Funding: Work partially supported by the US DOE through the US LHC Accelerator Research Program (LARP), and by US DOE under contract number DE-AC02-76SF00515.
A 400-MHz compact RF dipole (RFD) crab cavity design was jointly developed by Old Dominion University and SLAC under the support of US LARP program for the LHC HiLumi upgrade. The RFD cavity design is consisted of a rounded-square tank and two ridged deflecting poles, operating with a TE11-like dipole mode, which is the lowest mode of the cavity. A prototype RFD cavity is being manufactured and will be tested on the SPS beam line at CERN. The coaxial fundamental Power Coupler (FPC) of the prototype cavity was re-optimized to minimizing the power heating on the coupler internal antenna. A hi-pass filter HOM damping coupler was developed to achieve the required wakefield damping while maintaining a compact size to fit into the beam line space. In this paper, we will discuss the details of the RF optimization and tolerance analyses of the FPC and HOM couplers.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWI035

Beam Dynamics Studies of 499 MHz Superconducting RF-Dipole Deflecting Cavity System

3564

S.U. De Silva, K.E. Deitrick, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA

A 499 MHz deflecting cavity has been designed as a three-way beam spreader to separate an electron beam into 3 beams. The rf tests carried out on the superconducting rf-dipole cavity have demonstrated that a transverse voltage of 4.2 MV can be achieved with a single cavity. This paper discusses the beam dynamics on a deflecting structure operating in continuous-wave mode with a relativistic beam. The study includes the analysis on emittance growth, energy spread, and change in bunch size including effects due to field non-uniformities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI035

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWI036

Design and Prototyping of a 400 MHz RF-dipole Crabbing Cavity for the LHC High-Luminosity Upgrade

3568

S.U. De Silva, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA
Z. Li
SLAC, Menlo Park, California, USA
T.H. Nicol
Fermilab, Batavia, Illinois, USA

LHC High Luminosity Upgrade is in need of two crabbing systems that deflects the beam in both horizontal and vertical planes. The 400 MHz rf-dipole crabbing cavity system is capable of crabbing the proton beam in both planes. At present we are focusing our efforts on a complete crabbing system in the horizontal plane. Prior to LHC installation the crabbing system will be installed for beam test at SPS. The crabbing system consists of two rf-dipole cavities in the cryomodule. This paper discusses the electromagnetic design and mechanical properties of the rf-dipole crabbing system for SPS beam test.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI036

Export •

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WEPWI037

Imperfection and Tolerance Analysis of HOM Couplers for ODU/SLAC 400 MHz Crabbing Cavity

3572

S.U. De Silva, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA
Z. Li
SLAC, Menlo Park, California, USA
R.G. Olave
Old Dominion University, Norfolk, Virginia, USA

In preparation for the LHC High Luminosity upgrade, a 400 MHz crab cavity has been developed jointly at ODU/SLAC, including two higher order mode couplers designed to dampen the wakefields in order to comply with the impedance budget specified for the LHC system. During fabrication, assembly, and processing of the couplers, a number of imperfections may arise that could modify the higher order mode spectrum and the associated impedance for each mode. We present here a detailed study of the imperfections of the horizontal- and vertical- HOM couplers, and the associated allowed tolerances for manufacture, assembly and processing.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THZMS1

A New Class of Superconducting Structures for the Deflection and Crabbing of Particle Beams

S.U. De Silva
ODU, Norfolk, Virginia, USA

Recently, superconducting deflecting and crabbing cavities for particle accelerators and colliders have been an area of intense research. The future colliders pushing the energy and luminosity frontiers and particle accelerators with multi-experimental stations have expanded the need of deflecting/crabbing cavities. The current applications in need of such cavities operate at low frequencies and have also specifications with strict dimensional constraints, high operating transverse gradients, and tight impedance budgets. At low operating frequencies the use of standard cavities operating in TM110-like modes has been very challenging. A new type of superconducting deflecting/crabbing structure has been designed that has a wide range of applications. The new rf-dipole cavity operates in a TE11-like mode where several cavities have been fabricated, and tested. The rf performance shows that these structures are capable of operating at high transverse gradients and will be a very attractive deflecting/crabbing cavity for many current applications. At present, a 400 MHz rf-dipole crabbing cavity system is under development to be tested at SPS at LHC as part of the LHC High Luminosity Upgrade.

Slides THZMS1 [1.861 MB]

Export •

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