IPAC2021 - List of Authors (Sangroula, M.P.)

Paper	Title	Page
WEPAB032	Studies of the Short-Range Wakefields for the Electron Storage Ring in the Electron Ion Collider	2675
	G. Wang, M. Blaskiewicz, A. Blednykh, M.P. Sangroula BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. During the estimates of impedance budget for the Electron Storage Ring (ESR) of Electron-Ion Collider (EIC), various codes, including GdfidL, CST and ECHO3D, have been used to calculate the short-range wake-fields due to the vacuum components. The ECHO 3D code demonstrates more reliable results for the tapered type of structures rather than the GdfidL code, where the stepsize needs to be dramatically decreased to achieve a high-performance calculation. Impedance of the following components are discussed and compared in details: Interaction Region (IR) chamber, bellows, and synchrotron radiation mask (flange absorber).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB032
About •	paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 24 August 2021
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WEPAB193	Optimization of the Hadron Ring Stripline Injection Kicker for the EIC	3073
	M.P. Sangroula, C.J. Liaw, C. Liu, N. Tsoupas, B.P. Xiao, W. Zhang BNL, Upton, New York, USA X. Sun ANL, Lemont, Illinois, USA S. Verdú-Andrés Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy The Electron-Ion Collider (EIC) at Brookhaven National Laboratory is a high luminosity, ( ∼ 10³⁴ \textrm{cm}^-2 \textrm{s}^-1 ) accelerator facility colliding polarized electron beam with different ion species ranging from lighter nuclei (proton, deuterium) to heavier nuclei (gold, uranium). Design of a stripline injection kicker for the Hadron Storage Ring (HSR) of EIC for beams with the rigidity of ∼ 81 T-m poses some technical challenges due to expected shorter bunch spacing and higher peak current of EIC. This paper focuses on the optimization of the EIC hadron ring injection kicker. Starting from the 2D cross-section design which includes the selection of electrodes shape, we describe the optimization of the kicker’s cross-section. Then we discuss converting this 2D geometry to 3D by adding essential components for the stripline kicker and the 3D optimization techniques that we employed. Finally, we show simulation results for the optimized geometry including wakefields and Time Domain Reflection (TDR) from one feedthrough to another.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB193
About •	paper received ※ 21 May 2021 paper accepted ※ 28 June 2021 issue date ※ 14 August 2021
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WEPAB194	Feasibility of Using the Existing RHIC Stripline BPMs for the EIC	3077
	M.P. Sangroula, C. Liu, M.G. Minty, P. Thieberger BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The design of the Electron-Ion Collider (EIC) at Brookhaven National Laboratory (BNL) will utilize portions of the existing Relativistic Heavy Ion Collider (RHIC) for the EIC hadron ring. The EIC design calls for up to 10-times shorter ion bunches compared to the present RHIC operation. Higher single bunch peak currents will result in higher voltages to the output ports of the BPMs consequently producing more heating of the cryogenic signal cables connected to these output ports. Therefore, the existing stripline BPMs should be either upgraded or replaced with new ones. In this paper, we explore the potentially cost-effective approach by incorporating an RF-shielding piece into the existing BPMs as opposed to replacing them completely. Starting with the power delivered to the output ports, we present the proposed BPM modification with the RF-shielding piece. Then we discuss in detail the RF-shielding piece geometry including the dimension of RF slot and RF-fingers configuration. Finally, we present the optimization of the shielding piece and the mechanical tolerances required for its fabrication.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB194
About •	paper received ※ 21 May 2021 paper accepted ※ 28 June 2021 issue date ※ 15 August 2021
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THPAB238	An Overview of the Collective Effects and Impedance Calculation for the EIC	4266
	A. Blednykh, D.M. Gassner, B. Podobedov, S. Verdú-Andrés Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA M. Blaskiewicz, C. Hetzel, B. Lepore, V.H. Ranjbar, M.P. Sangroula, P. Thieberger, G. Wang, Q. Wu BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. A new high-luminosity Electron-Ion Collider (EIC) is being designed at Brookhaven National Laboratory (BNL). Stable operation of the electron beam at an average current of 2.5A within 1100 bunches with a 7mm bunch length is one of the challenging tasks in achieving an electron-proton luminosity of 1033-1034 cm^-2 ses⁻¹ range. Beam induced heating, short-range and long-range wakefield analysis is discussed for some of the vacuum components of the electron storage ring (ESR), the hadron storage ring (HSR), and the rapid cycling synchrotron (RCS) and as well as the impact of the collective effects on the beam stability.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB238
About •	paper received ※ 15 May 2021 paper accepted ※ 24 June 2021 issue date ※ 29 August 2021
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THPAB239	Impedance Optimization of the EIC Interaction Region Vacuum Chamber	4270
	A. Blednykh Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA E.C. Aschenauer, M. Blaskiewicz, C. Hetzel, M.P. Sangroula, G. Wang, H. Witte BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. The interaction region chamber has a complex geometry at the crossing location of electron and proton beam pipes. In the direction of the electron beam, the pipe is designed in a way to avoid joints with cavity characteristics. The horizontal slot on the upstream side and the tapered transition on the downstream side are applied to minimize the IR chamber contribution to the total impedance of the electron ring and to avoid generating Higher Order Modes and heating-related issues. The synchrotron radiation mask is included to protect the IR chamber from synchrotron radiation without significant aperture reduction. In the direction of the proton beam, the main area for optimization is the transition area right after the detector.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB239
About •	paper received ※ 15 May 2021 paper accepted ※ 24 June 2021 issue date ※ 24 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB195	Design and Optimization of a Low Frequency RF-Input Coupler for the IsoDAR RFQ	3081
	M.P. Sangroula, J.M. Conrad, D. Winklehner MIT, Cambridge, Massachusetts, USA M. Schuett BEVATECH, Frankfurt, Germany
	Funding: The RFQ-DIP project is supported by National Science Foundation grant \# PHY-1626069 and the Heising-Simons Foundation. The Isotope Decay-At-Rest experiment (IsoDAR) is a proposed underground experiment which is expected to be a definitive search for sterile neutrinos. IsoDAR uses an especially designed low-frequency spilt-coaxial radio frequency quadrupole (RFQ) to accelerate H²⁺ ions directly from the ion source into the main cyclotron accelerator. This paper mainly focuses on the design and optimization of a low frequency (32.8 MHz) RF-input coupler for the IsoDAR RFQ. Starting with a basic design, we determine its appropriate position for this coupler in the RFQ. Finally, we optimized the design to lower the input power without compromising the coupling efficiency.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB195
About •	paper received ※ 21 May 2021 paper accepted ※ 30 June 2021 issue date ※ 29 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Studies of the Short-Range Wakefields for the Electron Storage Ring in the Electron Ion Collider

2675

G. Wang, M. Blaskiewicz, A. Blednykh, M.P. Sangroula
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
During the estimates of impedance budget for the Electron Storage Ring (ESR) of Electron-Ion Collider (EIC), various codes, including GdfidL, CST and ECHO3D, have been used to calculate the short-range wake-fields due to the vacuum components. The ECHO 3D code demonstrates more reliable results for the tapered type of structures rather than the GdfidL code, where the stepsize needs to be dramatically decreased to achieve a high-performance calculation. Impedance of the following components are discussed and compared in details: Interaction Region (IR) chamber, bellows, and synchrotron radiation mask (flange absorber).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB032

About •

paper received ※ 19 May 2021 paper accepted ※ 10 June 2021 issue date ※ 24 August 2021

Export •

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

WEPAB193

Optimization of the Hadron Ring Stripline Injection Kicker for the EIC

3073

M.P. Sangroula, C.J. Liaw, C. Liu, N. Tsoupas, B.P. Xiao, W. Zhang
BNL, Upton, New York, USA
X. Sun
ANL, Lemont, Illinois, USA
S. Verdú-Andrés
Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
The Electron-Ion Collider (EIC) at Brookhaven National Laboratory is a high luminosity, ( ∼ 10³⁴ \textrm{cm}^-2 \textrm{s}^-1 ) accelerator facility colliding polarized electron beam with different ion species ranging from lighter nuclei (proton, deuterium) to heavier nuclei (gold, uranium). Design of a stripline injection kicker for the Hadron Storage Ring (HSR) of EIC for beams with the rigidity of ∼ 81 T-m poses some technical challenges due to expected shorter bunch spacing and higher peak current of EIC. This paper focuses on the optimization of the EIC hadron ring injection kicker. Starting from the 2D cross-section design which includes the selection of electrodes shape, we describe the optimization of the kicker’s cross-section. Then we discuss converting this 2D geometry to 3D by adding essential components for the stripline kicker and the 3D optimization techniques that we employed. Finally, we show simulation results for the optimized geometry including wakefields and Time Domain Reflection (TDR) from one feedthrough to another.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB193

About •

paper received ※ 21 May 2021 paper accepted ※ 28 June 2021 issue date ※ 14 August 2021

Export •

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

WEPAB194

Feasibility of Using the Existing RHIC Stripline BPMs for the EIC

3077

M.P. Sangroula, C. Liu, M.G. Minty, P. Thieberger
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The design of the Electron-Ion Collider (EIC) at Brookhaven National Laboratory (BNL) will utilize portions of the existing Relativistic Heavy Ion Collider (RHIC) for the EIC hadron ring. The EIC design calls for up to 10-times shorter ion bunches compared to the present RHIC operation. Higher single bunch peak currents will result in higher voltages to the output ports of the BPMs consequently producing more heating of the cryogenic signal cables connected to these output ports. Therefore, the existing stripline BPMs should be either upgraded or replaced with new ones. In this paper, we explore the potentially cost-effective approach by incorporating an RF-shielding piece into the existing BPMs as opposed to replacing them completely. Starting with the power delivered to the output ports, we present the proposed BPM modification with the RF-shielding piece. Then we discuss in detail the RF-shielding piece geometry including the dimension of RF slot and RF-fingers configuration. Finally, we present the optimization of the shielding piece and the mechanical tolerances required for its fabrication.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB194

About •

paper received ※ 21 May 2021 paper accepted ※ 28 June 2021 issue date ※ 15 August 2021

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

THPAB238

An Overview of the Collective Effects and Impedance Calculation for the EIC

4266

A. Blednykh, D.M. Gassner, B. Podobedov, S. Verdú-Andrés
Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
M. Blaskiewicz, C. Hetzel, B. Lepore, V.H. Ranjbar, M.P. Sangroula, P. Thieberger, G. Wang, Q. Wu
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
A new high-luminosity Electron-Ion Collider (EIC) is being designed at Brookhaven National Laboratory (BNL). Stable operation of the electron beam at an average current of 2.5A within 1100 bunches with a 7mm bunch length is one of the challenging tasks in achieving an electron-proton luminosity of 1033-1034 cm^-2 ses⁻¹ range. Beam induced heating, short-range and long-range wakefield analysis is discussed for some of the vacuum components of the electron storage ring (ESR), the hadron storage ring (HSR), and the rapid cycling synchrotron (RCS) and as well as the impact of the collective effects on the beam stability.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB238

About •

paper received ※ 15 May 2021 paper accepted ※ 24 June 2021 issue date ※ 29 August 2021

Export •

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

THPAB239

Impedance Optimization of the EIC Interaction Region Vacuum Chamber

4270

A. Blednykh
Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
E.C. Aschenauer, M. Blaskiewicz, C. Hetzel, M.P. Sangroula, G. Wang, H. Witte
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The interaction region chamber has a complex geometry at the crossing location of electron and proton beam pipes. In the direction of the electron beam, the pipe is designed in a way to avoid joints with cavity characteristics. The horizontal slot on the upstream side and the tapered transition on the downstream side are applied to minimize the IR chamber contribution to the total impedance of the electron ring and to avoid generating Higher Order Modes and heating-related issues. The synchrotron radiation mask is included to protect the IR chamber from synchrotron radiation without significant aperture reduction. In the direction of the proton beam, the main area for optimization is the transition area right after the detector.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB239

About •

paper received ※ 15 May 2021 paper accepted ※ 24 June 2021 issue date ※ 24 August 2021

Export •

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

WEPAB195

Design and Optimization of a Low Frequency RF-Input Coupler for the IsoDAR RFQ

3081

M.P. Sangroula, J.M. Conrad, D. Winklehner
MIT, Cambridge, Massachusetts, USA
M. Schuett
BEVATECH, Frankfurt, Germany

Funding: The RFQ-DIP project is supported by National Science Foundation grant \# PHY-1626069 and the Heising-Simons Foundation.
The Isotope Decay-At-Rest experiment (IsoDAR) is a proposed underground experiment which is expected to be a definitive search for sterile neutrinos. IsoDAR uses an especially designed low-frequency spilt-coaxial radio frequency quadrupole (RFQ) to accelerate H²⁺ ions directly from the ion source into the main cyclotron accelerator. This paper mainly focuses on the design and optimization of a low frequency (32.8 MHz) RF-input coupler for the IsoDAR RFQ. Starting with a basic design, we determine its appropriate position for this coupler in the RFQ. Finally, we optimized the design to lower the input power without compromising the coupling efficiency.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB195

About •

paper received ※ 21 May 2021 paper accepted ※ 30 June 2021 issue date ※ 29 August 2021

Export •

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