IPAC2014 - List of Authors (Delayen, J.R.)

Paper	Title	Page
MOPRO011	Employing Twin Crabbing Cavities to Address Variable Transverse Coupling of Beams in the MEIC*	80
	A. Castilla DCI-UG, León, Mexico A. Castilla, J.R. Delayen, V.S. Morozov, T. Satogata JLab, Newport News, Virginia, USA A. Castilla, J.R. Delayen, V.S. Morozov, T. Satogata ODU, Norfolk, Virginia, USA
	Funding: *Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The design strategy of the Medium Energy Electron-Ion Collider (MEIC) at Jefferson Lab contemplates both matching of the emittance aspect ratios and a 50 mrad crossing angle along with crab crossing scheme for both electron and ion beams over the energy range (√s=20-70 GeV) to achieve high luminosities at the interaction points (IPs). However, the desired locations for placing the crabbing cavities may include regions where the transverse degrees of freedom of the beams are coupled with variable coupling strength that depends on the collider rings’ magnetic elements (solenoids and skew quadrupoles). In this work we explore the feasibility of employing twin rf dipoles that produce a variable direction crabbing kick to account for a range of transverse coupling of both beams.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO011
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WEPRI077	Cryogenic Test of a 750 MHz Superconducting RF Dipole Crabbing Cavity*	2672
	A. Castilla, J.R. Delayen ODU, Norfolk, Virginia, USA A. Castilla, J.R. Delayen, H. Park JLab, Newport News, Virginia, USA A. Castilla DCI-UG, León, Mexico
	Funding: *Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. With resources of NERSC, under U.S. DOE contract No. DE-AC02-05CH11231. A superconducting rf dipole cavity has been designed to address the challenges of a high repetition rate (750 MHz), high current for both electron/ion species (0.5/3 A per bunch), and large crossing angle (50 mrad) at the interaction points (IPs) crabbing system for the Medium Energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The cavity prototype built at Niowave, Inc. has been tested at the Jefferson Lab facilities. In this work we present a detailed analysis of the prototype cavity performance at 4 K and 2 K, corroborating the absence of hard multipacting barriers that could limit the desired transverse fields, along with the surface resistance (R_s) temperature dependency.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI077
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WEPRI075	A Compact Beam Spreader using RF Deflecting Cavities for the LCLS-II	2666
	S.U. De Silva, J.R. Delayen, R.G. Olave ODU, Norfolk, Virginia, USA L.R. Doolittle, M. Placidi, A. Ratti LBNL, Berkeley, California, USA P. Emma SLAC, Menlo Park, California, USA
	The LCLS-II project currently under development is designed to accelerate electron bunches up to 4 GeV and transport them to one of two FEL undulators located more than 2 km downstream of the end of the LCLS-II linac. The upgrade requires a spreader system to separate the baseline electron bunches and transport them to two undulator lines or a local dump. Fast bipolar kickers (FK) or transverse electric rf deflectors (RFD) are considered as fast-switching devices (FSD). In the RFD approach described here three design options operating at 325 MHz are studied including a superconducting rf-dipole cavity, a normal conducting rf-dipole cavity, and a normal conducting 4-rod cavity. Optional compact splitting schemes involving a combination of vertical and horizontal initial deflections are addressed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI075
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WEPRI076	Higher Order Mode Damping in Superconducting Spoke Cavities	2669
	C.S. Hopper, J.R. Delayen ODU, Norfolk, Virginia, USA
	Parasitic higher order modes (HOMs) can be severely detrimental to the performance of superconducting cavities. For this reason, the mode spectrum and beam coupling strength must be examined in detail to determine which modes must be damped. One advantage of the spoke cavity geometry is that couplers can be placed on the outer body of the cavity rather than in the beam line space. We present an overview of the HOM properties of spoke cavities and methods for suppressing the most harmful ones.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI076
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Paper

Title

Page

Employing Twin Crabbing Cavities to Address Variable Transverse Coupling of Beams in the MEIC*

80

A. Castilla
DCI-UG, León, Mexico
A. Castilla, J.R. Delayen, V.S. Morozov, T. Satogata
JLab, Newport News, Virginia, USA
A. Castilla, J.R. Delayen, V.S. Morozov, T. Satogata
ODU, Norfolk, Virginia, USA

Funding: *Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The design strategy of the Medium Energy Electron-Ion Collider (MEIC) at Jefferson Lab contemplates both matching of the emittance aspect ratios and a 50 mrad crossing angle along with crab crossing scheme for both electron and ion beams over the energy range (√s=20-70 GeV) to achieve high luminosities at the interaction points (IPs). However, the desired locations for placing the crabbing cavities may include regions where the transverse degrees of freedom of the beams are coupled with variable coupling strength that depends on the collider rings’ magnetic elements (solenoids and skew quadrupoles). In this work we explore the feasibility of employing twin rf dipoles that produce a variable direction crabbing kick to account for a range of transverse coupling of both beams.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO011

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WEPRI077

Cryogenic Test of a 750 MHz Superconducting RF Dipole Crabbing Cavity*

2672

A. Castilla, J.R. Delayen
ODU, Norfolk, Virginia, USA
A. Castilla, J.R. Delayen, H. Park
JLab, Newport News, Virginia, USA
A. Castilla
DCI-UG, León, Mexico

Funding: *Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. With resources of NERSC, under U.S. DOE contract No. DE-AC02-05CH11231.
A superconducting rf dipole cavity has been designed to address the challenges of a high repetition rate (750 MHz), high current for both electron/ion species (0.5/3 A per bunch), and large crossing angle (50 mrad) at the interaction points (IPs) crabbing system for the Medium Energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The cavity prototype built at Niowave, Inc. has been tested at the Jefferson Lab facilities. In this work we present a detailed analysis of the prototype cavity performance at 4 K and 2 K, corroborating the absence of hard multipacting barriers that could limit the desired transverse fields, along with the surface resistance (R_s) temperature dependency.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI077

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

WEPRI075

A Compact Beam Spreader using RF Deflecting Cavities for the LCLS-II

2666

S.U. De Silva, J.R. Delayen, R.G. Olave
ODU, Norfolk, Virginia, USA
L.R. Doolittle, M. Placidi, A. Ratti
LBNL, Berkeley, California, USA
P. Emma
SLAC, Menlo Park, California, USA

The LCLS-II project currently under development is designed to accelerate electron bunches up to 4 GeV and transport them to one of two FEL undulators located more than 2 km downstream of the end of the LCLS-II linac. The upgrade requires a spreader system to separate the baseline electron bunches and transport them to two undulator lines or a local dump. Fast bipolar kickers (FK) or transverse electric rf deflectors (RFD) are considered as fast-switching devices (FSD). In the RFD approach described here three design options operating at 325 MHz are studied including a superconducting rf-dipole cavity, a normal conducting rf-dipole cavity, and a normal conducting 4-rod cavity. Optional compact splitting schemes involving a combination of vertical and horizontal initial deflections are addressed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI075

Export •

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

WEPRI076

Higher Order Mode Damping in Superconducting Spoke Cavities

2669

C.S. Hopper, J.R. Delayen
ODU, Norfolk, Virginia, USA

Parasitic higher order modes (HOMs) can be severely detrimental to the performance of superconducting cavities. For this reason, the mode spectrum and beam coupling strength must be examined in detail to determine which modes must be damped. One advantage of the spoke cavity geometry is that couplers can be placed on the outer body of the cavity rather than in the beam line space. We present an overview of the HOM properties of spoke cavities and methods for suppressing the most harmful ones.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI076

Export •

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