IPAC2018 - List of Authors (Delayen, J.R.)

Paper	Title	Page
THPMK108	Production of Magnetized Electron Beam from a DC High Voltage Photogun	4567
	M.A. Mamun, P.A. Adderley, J. F. Benesch, D.B. Bullard, J.R. Delayen, J.M. Grames, J. Guo, F.E. Hannon, J. Hansknecht, C. Hernandez-Garcia, R. Kazimi, G.A. Krafft, M. Poelker, R. Suleiman, M.G. Tiefenback, Y.W. Wang, S. Zhang JLab, Newport News, Virginia, USA S.A.K. Wijethunga ODU, Norfolk, Virginia, USA
	Funding: This work is supported by the Department of Energy, Laboratory Directed Research and Development funding, under contract DE-AC05-06OR23177 Bunched-beam electron cooling is a key feature of all proposed designs of the future electron-ion collider, and a requirement for achieving the highest promised collision luminosity. At the Jefferson Lab Electron Ion Collider (JLEIC), fast cooling of ion beams will be accomplished via so-called 'magnetized cooling' implemented using a recirculator ring that employs an energy recovery linac. In this contribution, we describe the production of magnetized electron beam using a compact 300 kV DC high voltage photogun with an inverted insulator geometry, and using alkali-antimonide photocathodes. Beam magnetization was assessed using a modest diagnostic beamline that includes YAG view screens used to measure the rotation of the electron beamlet passing through a narrow upstream aperture. Magnetization results are presented for different gun bias voltages and for different laser spot sizes at the photocathode, using 532 nm lasers with DC and RF time structure. Photocathode lifetime was measured at currents up to 4.5 mA, with and without beam magnetization.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK108
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THPAK070	Coupled Bunch Instability from JLEIC Crab Cavity Higher Order Modes	3392
SUSPF079	use link to see paper's listing under its alternate paper code
	S.I. Sosa Guitron, S.U. De Silva, J.R. Delayen, H. Park ODU, Norfolk, Virginia, USA R. Li, V.S. Morozov, H. Park JLab, Newport News, Virginia, USA
	Particle bunches traveling in a ring can excite wakefields inside any radio-frequency element present. These electromagnetic modes can resonate long enough and interact with subsequent passing bunches. A coherent oscillation between bunches can quickly become an instability and needs to be addressed. The Jefferson Lab electron ion collider has a large 50 mrad crossing angle and thus relies on bunch crabbing to achieve high luminosity. Bunch crabbing is done with compact superconducting rf dipole cavities. We study coupled bunch oscillations driven by the higher order modes of multicell RFD crab cavities under study for JLEIC, we calculate the instability growth time assuming a symmetric beam spectrum, identify the HOMs driving the instability and discuss mitigation measures.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK070
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THPAK071	Simulation Study of the Magnetized Electron Beam	3395
SUSPF086	use link to see paper's listing under its alternate paper code
	S.A.K. Wijethunga, J.R. Delayen, G.A. Krafft ODU, Norfolk, Virginia, USA J. F. Benesch, F.E. Hannon, G.A. Krafft, M.A. Mamun, M. Poelker, R. Suleiman JLab, Newport News, Virginia, USA
	Funding: This work is supported by the Department of Energy, Laboratory Directed Research and Development funding, under contract DE-AC05-06OR23177 Electron cooling of the ion beam plays an important role in electron ion colliders to obtain the required high luminosity. This cooling efficiency can be enhanced by using a magnetized electron beam, where the cooling process occurs inside a solenoid field. This paper compares the predictions of ASTRA and GPT simulations to measurements made using a DC high voltage photogun producing magnetized electron beam, related to beam size and rotation angles as a function of the photogun magnetizing solenoid and other parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK071
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THPAL067	Room Temperature Measurements of Higher Order Modes for the SPS Prototype RF-Dipole Crabbing Cavity	3805
	S.U. De Silva, J.R. Delayen, H. Park ODU, Norfolk, Virginia, USA P. Berrutti Fermilab, Batavia, Illinois, USA N.A. Huque, H. Park JLab, Newport News, Virginia, USA
	LHC High Luminosity Upgrade will be developing two local crabbing systems to increase the luminosity of the colliding bunches at the ATLAS and CMS experiments. One of the crabbing systems uses the rf-dipole cavity design that will be crabbing the beam in the horizontal plane. The fully integrated crabbing cavity has two higher order mode couplers in damping those excited modes. Currently two sets of HOM couplers have been fabricated at Jefferson Lab for prototyping and testing with the LARP crabbing cavities. This paper presents the measurements of the higher order modes with the prototype HOM couplers carried out at room temperature.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL067
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Paper

Title

Page

Production of Magnetized Electron Beam from a DC High Voltage Photogun

4567

M.A. Mamun, P.A. Adderley, J. F. Benesch, D.B. Bullard, J.R. Delayen, J.M. Grames, J. Guo, F.E. Hannon, J. Hansknecht, C. Hernandez-Garcia, R. Kazimi, G.A. Krafft, M. Poelker, R. Suleiman, M.G. Tiefenback, Y.W. Wang, S. Zhang
JLab, Newport News, Virginia, USA
S.A.K. Wijethunga
ODU, Norfolk, Virginia, USA

Funding: This work is supported by the Department of Energy, Laboratory Directed Research and Development funding, under contract DE-AC05-06OR23177
Bunched-beam electron cooling is a key feature of all proposed designs of the future electron-ion collider, and a requirement for achieving the highest promised collision luminosity. At the Jefferson Lab Electron Ion Collider (JLEIC), fast cooling of ion beams will be accomplished via so-called 'magnetized cooling' implemented using a recirculator ring that employs an energy recovery linac. In this contribution, we describe the production of magnetized electron beam using a compact 300 kV DC high voltage photogun with an inverted insulator geometry, and using alkali-antimonide photocathodes. Beam magnetization was assessed using a modest diagnostic beamline that includes YAG view screens used to measure the rotation of the electron beamlet passing through a narrow upstream aperture. Magnetization results are presented for different gun bias voltages and for different laser spot sizes at the photocathode, using 532 nm lasers with DC and RF time structure. Photocathode lifetime was measured at currents up to 4.5 mA, with and without beam magnetization.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK108

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THPAK070

Coupled Bunch Instability from JLEIC Crab Cavity Higher Order Modes

3392

SUSPF079

use link to see paper's listing under its alternate paper code

S.I. Sosa Guitron, S.U. De Silva, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA
R. Li, V.S. Morozov, H. Park
JLab, Newport News, Virginia, USA

Particle bunches traveling in a ring can excite wakefields inside any radio-frequency element present. These electromagnetic modes can resonate long enough and interact with subsequent passing bunches. A coherent oscillation between bunches can quickly become an instability and needs to be addressed. The Jefferson Lab electron ion collider has a large 50 mrad crossing angle and thus relies on bunch crabbing to achieve high luminosity. Bunch crabbing is done with compact superconducting rf dipole cavities. We study coupled bunch oscillations driven by the higher order modes of multicell RFD crab cavities under study for JLEIC, we calculate the instability growth time assuming a symmetric beam spectrum, identify the HOMs driving the instability and discuss mitigation measures.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK070

Export •

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

THPAK071

Simulation Study of the Magnetized Electron Beam

3395

SUSPF086

use link to see paper's listing under its alternate paper code

S.A.K. Wijethunga, J.R. Delayen, G.A. Krafft
ODU, Norfolk, Virginia, USA
J. F. Benesch, F.E. Hannon, G.A. Krafft, M.A. Mamun, M. Poelker, R. Suleiman
JLab, Newport News, Virginia, USA

Funding: This work is supported by the Department of Energy, Laboratory Directed Research and Development funding, under contract DE-AC05-06OR23177
Electron cooling of the ion beam plays an important role in electron ion colliders to obtain the required high luminosity. This cooling efficiency can be enhanced by using a magnetized electron beam, where the cooling process occurs inside a solenoid field. This paper compares the predictions of ASTRA and GPT simulations to measurements made using a DC high voltage photogun producing magnetized electron beam, related to beam size and rotation angles as a function of the photogun magnetizing solenoid and other parameters.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK071

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

THPAL067

Room Temperature Measurements of Higher Order Modes for the SPS Prototype RF-Dipole Crabbing Cavity

3805

S.U. De Silva, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA
P. Berrutti
Fermilab, Batavia, Illinois, USA
N.A. Huque, H. Park
JLab, Newport News, Virginia, USA

LHC High Luminosity Upgrade will be developing two local crabbing systems to increase the luminosity of the colliding bunches at the ATLAS and CMS experiments. One of the crabbing systems uses the rf-dipole cavity design that will be crabbing the beam in the horizontal plane. The fully integrated crabbing cavity has two higher order mode couplers in damping those excited modes. Currently two sets of HOM couplers have been fabricated at Jefferson Lab for prototyping and testing with the LARP crabbing cavities. This paper presents the measurements of the higher order modes with the prototype HOM couplers carried out at room temperature.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL067

Export •

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