IPAC2016 - List of Authors (Chung, M.)

Paper	Title	Page
MOPMR012	Studies of Buffer Gas Cooling of Ion Beams in an RFQ Cooler and Their Transport to the EBIS Charge Breeder	248
SUPSS075	use link to see paper's listing under its alternate paper code
	K.H. Yoo, M. Chung UNIST, Ulsan, Republic of Korea H.J. Son IBS, Daejeon, Republic of Korea
	In rare isotope accelerator facilities, an RFQ cooler is often used to manipulate ions. The RFQ cooler is a de-vice to effectively cool and confine ions in gaseous envi-ronment. The RFQ cooler provides a radial electric force to the beam by applying RF voltages to the quadrupole electrode structures, and axial force by applying different DC voltages to the segmented electrodes. The ions are trapped inside the potential well of the RFQ cooler formed by the DC fields, so that they have more colli-sions with the buffer gas. Several important parameters such as transverse emittance can be improved when ion beams are extracted from the RFQ cooler. In order to design an efficient RFQ cooler, which can properly match the ion beams into the EBIS charge breeder, it is essential to analyze evolutions of the transverse emittance and transmission efficiency through the RFQ cooler. Moreo-ver, to minimize emittance growth and maximize trans-mission efficiency, the beam transport line to the EBIS charge breeder needs to be optimized. In this work, we study the methods to apply the mechanism of buffer gas cooling in RFQ cooler to G4beamline and the beam transport line to EBIS charge breeder to TRACK.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR012
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MOPOR037	Beam Halo Measurements using Vibrating Wire at the KOMAC	680
SUPSS057	use link to see paper's listing under its alternate paper code
	D. Choe, M. Chung, S.Y. Kim UNIST, Ulsan, Republic of Korea S.G. Arutunian, A.V. Margaryan ANSL, Yerevan, Armenia E.G. Lazareva YSU, Yerevan, Armenia
	In high-intensity particle accelerators, due to the fact that preventing beam loss plays a crucial role in con-ducting any experiments, it is important to measure and control the beam halo. Fortunately, it is feasible nowadays to measure the beam halo region thanks to the development of several sensitive beam scanning methods, including the vibrating wire technique. Since the vibrating wire is exceptionally sensitive to the heat deposition by the beam particles, it can be used to scanning the beam profile. This study will be concentrated on the precise beam profile measurement using the vibrating wire at the Korea Multi-Purpose Accelerator Complex (KOMAC) facility. First, we describe the best condition to construct beam profile measurement experiment. Finally, we present the results of the beam halo measurements performed with 20 MeV proton beam at the KOMAC facility
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR037
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TUOAB01	Optimization of the Dechirper for Electron Bunches of Arbitrary Longitudinal Shapes	1054
SUPSS049	use link to see paper's listing under its alternate paper code
	J.M. Seok, M. Chung UNIST, Ulsan, Republic of Korea J.H. Han, J.H. Hong, H.-S. Kang PAL, Pohang, Kyungbuk, Republic of Korea
	Dechirper is a passive device composed of a vacuum chamber of two corrugated, metallic plates with an adjustable gap. By introducing a small offset in the dechirper with respect to the reference axis, one might generate transverse wakefields and use the dechirper as a deflector. Understanding the interactions between electron beams of various longitudinal shapes with the wakefields generated by the dechirper is important to assess the feasibility of the dechirper for use as a deflector. Recently, using a set of alpha-BBO crystals, shaping of laser pulses and electron bunches on the order of ps is tested at the Injector Test Facility (ITF) of Pohang Accelerator Laboratory (PAL). Furthermore, we have investigated propagation of electron bunches of arbitrary longitudinal shapes through the dechirper. In the numerical simulations, we observed that the arbitrary electron beams were successful deflected except for lethal beam shape problems. Hence, in this work, we study optimization of the dechirper for electron bunches of arbitrary longitudinal shapes, using analytical theory and numerical simulations with the ASTRA and ELEGANT codes.
	Slides TUOAB01 [1.631 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOAB01
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WEPMY016	Development of RF System for Measuring Plasma Density Modulation of Proton Beam-driven Plasma Wakefield	2582
SUPSS031	use link to see paper's listing under its alternate paper code
	S.Y. Kim, M. Chung UNIST, Ulsan, Republic of Korea
	Proton beam-driven plasma wakefield acceleration technique using the proton beam of Super Proton Syn-chrotron (SPS) at CERN has been actively researched these days. Plasma density modulation due to the proton beam will generate high-gradient's electric field within the modulated plasma. The key role is Self-Modulation Instability (SMI) of the long proton beam. To understand SMI phenomena, we have studied RF system such as heterodyne system for measuring modulated plasma den-sity caused by the SMI. In this work, we design the details of the RF system and optical system of focusing millimetre-sized electromagnetic wave using CODE V and plasma-electromagnetic wave interactions using simulation tools.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY016
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WEPMY017	Numerical Studies of Self Modulation Instability in the Beam-driven Plasma Wakefield Experiments	2585
SUPSS035	use link to see paper's listing under its alternate paper code
	K. Moon, M. Chung UNIST, Ulsan, Republic of Korea
	Proton beam-driven plasma wakefield acceleration was recently proposed as a way to bring electrons to TeV energy range in a single plasma section. When the ultra-relativistic long proton beam propagates into the plasmas, this bunch splits into many small bunches. This phenomenon is known as a Self-Modulation Instability (SMI), and its characteristics depend on the ratio of bunch length and plasma wavelength. In this study, we first introduce a Particle-In-Cell (PIC) code WARP, focusing on the basis of parallel version structure. Through numerical simulations using the WARP, we investigate the characteristics of the SMI and propose possible experimental setup at the Injector Test Facility (ITF) of Pohang Accelerator Laboratory (PAL). Also, we present dependencies of the witness beam quality on both the driver beam and plasma parameters.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY017
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

MOPMR012

Studies of Buffer Gas Cooling of Ion Beams in an RFQ Cooler and Their Transport to the EBIS Charge Breeder

248

SUPSS075

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

K.H. Yoo, M. Chung
UNIST, Ulsan, Republic of Korea
H.J. Son
IBS, Daejeon, Republic of Korea

In rare isotope accelerator facilities, an RFQ cooler is often used to manipulate ions. The RFQ cooler is a de-vice to effectively cool and confine ions in gaseous envi-ronment. The RFQ cooler provides a radial electric force to the beam by applying RF voltages to the quadrupole electrode structures, and axial force by applying different DC voltages to the segmented electrodes. The ions are trapped inside the potential well of the RFQ cooler formed by the DC fields, so that they have more colli-sions with the buffer gas. Several important parameters such as transverse emittance can be improved when ion beams are extracted from the RFQ cooler. In order to design an efficient RFQ cooler, which can properly match the ion beams into the EBIS charge breeder, it is essential to analyze evolutions of the transverse emittance and transmission efficiency through the RFQ cooler. Moreo-ver, to minimize emittance growth and maximize trans-mission efficiency, the beam transport line to the EBIS charge breeder needs to be optimized. In this work, we study the methods to apply the mechanism of buffer gas cooling in RFQ cooler to G4beamline and the beam transport line to EBIS charge breeder to TRACK.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR012

Export •

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

MOPOR037

Beam Halo Measurements using Vibrating Wire at the KOMAC

680

SUPSS057

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

D. Choe, M. Chung, S.Y. Kim
UNIST, Ulsan, Republic of Korea
S.G. Arutunian, A.V. Margaryan
ANSL, Yerevan, Armenia
E.G. Lazareva
YSU, Yerevan, Armenia

In high-intensity particle accelerators, due to the fact that preventing beam loss plays a crucial role in con-ducting any experiments, it is important to measure and control the beam halo. Fortunately, it is feasible nowadays to measure the beam halo region thanks to the development of several sensitive beam scanning methods, including the vibrating wire technique. Since the vibrating wire is exceptionally sensitive to the heat deposition by the beam particles, it can be used to scanning the beam profile. This study will be concentrated on the precise beam profile measurement using the vibrating wire at the Korea Multi-Purpose Accelerator Complex (KOMAC) facility. First, we describe the best condition to construct beam profile measurement experiment. Finally, we present the results of the beam halo measurements performed with 20 MeV proton beam at the KOMAC facility

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR037

Export •

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

TUOAB01

Optimization of the Dechirper for Electron Bunches of Arbitrary Longitudinal Shapes

1054

SUPSS049

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

J.M. Seok, M. Chung
UNIST, Ulsan, Republic of Korea
J.H. Han, J.H. Hong, H.-S. Kang
PAL, Pohang, Kyungbuk, Republic of Korea

Dechirper is a passive device composed of a vacuum chamber of two corrugated, metallic plates with an adjustable gap. By introducing a small offset in the dechirper with respect to the reference axis, one might generate transverse wakefields and use the dechirper as a deflector. Understanding the interactions between electron beams of various longitudinal shapes with the wakefields generated by the dechirper is important to assess the feasibility of the dechirper for use as a deflector. Recently, using a set of alpha-BBO crystals, shaping of laser pulses and electron bunches on the order of ps is tested at the Injector Test Facility (ITF) of Pohang Accelerator Laboratory (PAL). Furthermore, we have investigated propagation of electron bunches of arbitrary longitudinal shapes through the dechirper. In the numerical simulations, we observed that the arbitrary electron beams were successful deflected except for lethal beam shape problems. Hence, in this work, we study optimization of the dechirper for electron bunches of arbitrary longitudinal shapes, using analytical theory and numerical simulations with the ASTRA and ELEGANT codes.

Slides TUOAB01 [1.631 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOAB01

Export •

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

WEPMY016

Development of RF System for Measuring Plasma Density Modulation of Proton Beam-driven Plasma Wakefield

2582

SUPSS031

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

S.Y. Kim, M. Chung
UNIST, Ulsan, Republic of Korea

Proton beam-driven plasma wakefield acceleration technique using the proton beam of Super Proton Syn-chrotron (SPS) at CERN has been actively researched these days. Plasma density modulation due to the proton beam will generate high-gradient's electric field within the modulated plasma. The key role is Self-Modulation Instability (SMI) of the long proton beam. To understand SMI phenomena, we have studied RF system such as heterodyne system for measuring modulated plasma den-sity caused by the SMI. In this work, we design the details of the RF system and optical system of focusing millimetre-sized electromagnetic wave using CODE V and plasma-electromagnetic wave interactions using simulation tools.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY016

Export •

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

WEPMY017

Numerical Studies of Self Modulation Instability in the Beam-driven Plasma Wakefield Experiments

2585

SUPSS035

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

K. Moon, M. Chung
UNIST, Ulsan, Republic of Korea

Proton beam-driven plasma wakefield acceleration was recently proposed as a way to bring electrons to TeV energy range in a single plasma section. When the ultra-relativistic long proton beam propagates into the plasmas, this bunch splits into many small bunches. This phenomenon is known as a Self-Modulation Instability (SMI), and its characteristics depend on the ratio of bunch length and plasma wavelength. In this study, we first introduce a Particle-In-Cell (PIC) code WARP, focusing on the basis of parallel version structure. Through numerical simulations using the WARP, we investigate the characteristics of the SMI and propose possible experimental setup at the Injector Test Facility (ITF) of Pohang Accelerator Laboratory (PAL). Also, we present dependencies of the witness beam quality on both the driver beam and plasma parameters.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY017

Export •

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