IPAC2013 - List of Authors (Hwang, J.G.)

Paper	Title	Page
TUPWO038	Start-to-end Simulations for Heavy-ion Accelerator of RISP	1958
	E.-S. Kim, S.W. Jang KNU, Deagu, Republic of Korea J. Bahng, J.G. Hwang Kyungpook National University, Daegu, Republic of Korea B. Choi, D. Jeon, H.J. Kim, H.J. Kim IBS, Daejeon, Republic of Korea
	RAON has been designed as a facility for rare isotope accelerator at Korea. The aceelerator consists of 28 GHz superconducting ion source, LEBT, RFQ, MEBT, superconducting linac and HEBT. The linac accelerates ion beams to 200 MeV/u with a beam power of 400 kW. Start-to-End simulations are performed from ECR-IS to HEBT and the detailed beam simulation results are presented. The beam dynamics issues are also discussed.

WEPEA032	Estimation and Correction of the Uncontrolled Beam Loss due to the Alignment Error in the Low-energy Linear Accelerator of RAON	2570
	J.G. Hwang, E.-S. Kim Kyungpook National University, Daegu, Republic of Korea D. Jeon, H.J. Kim IBS, Daejeon, Republic of Korea
	RAON(Rare isotope Accelerator Of Newness) mainly consists of the front-end system, ISOL system , re-accelerator for ISOL system, charge stripper section and main linear accelerator(Linac) for ECR ion source. Since the beam energy at the down-stream of the front-end system is low, 0.3~0.5 MeV/u, the trajectories of the beam is very sensitive the alignment error of the magnets and cavities at the entrance of the main Linac. It can be caused the uncontrolled beam loss due to the large amplitude of the trajectory. The effect of the alignment errors of the magnets and cavities is estimated and corrected by using analytical model which is based on analytical model and code TRACK. The calculation result based on the analytical model agrees very well with the simulation by using the TRACK code. Using the analytical model, the position and number of the corrector and Beam Position Monitor(BPM) in low energy Linac was determined to compensate the amplification of the beam trajectory under 400 um. We will present the result of the estimation of the alignment error and the correction using steering magnet with strip-line Beam Position Monitor (BPM) in a low energy section.

WEPEA033	Optimization of Injector System for Early Commissioning Phase of Compact-ERL.	2573
	J.G. Hwang, E.-S. Kim Kyungpook National University, Daegu, Republic of Korea T. Miyajima KEK, Ibaraki, Japan
	Injector system of Compact-Energy Recovery Linear accelerator, which is currently develping in Photon Factory of KEK at Japan, consists of the photo-cathode DC gun, two solenoids, a 1.3 GHz buncher ,three 1.3 GHz 2 cell injector cavities, 5 quadrupole magnet and merger section. Target values of beam produced by the injector system are kinetic energy of 5 MeV, the normalized transverse emittance of under 0.1 mm-mrad and the bunch length of under 3 ps with the 7.7 pC charge per bunch and the repetition rate of 1.3 Ghz. In this low energy region, the effect of the space charge is dominated to cause the emittance growth. The optimization is performed by using MOGA (Multi-Object Genetic Algorithm) with code GPT to consider the effect of space charge under optimization. The code General Particle Tracer (GPT) is a 3D Paricle-In-Cell(PIC) code based on multi-layer object-oriented design. Using this method with code GPT, the target values was achieved at the exit of the merger section such as the normalized emittance of 0.1 mm-mrad with bunch length of 3 ps and kinetic energy of 5 MeV.

WEPEA034	Study on the Beam Dynamics in the RISP Driver Linac	2576
	H.J. Kim, H.J. Jang, D. Jeon IBS, Daejeon, Republic of Korea J.G. Hwang Kyungpook National University, Daegu, Republic of Korea E.-S. Kim KNU, Deagu, Republic of Korea
	Abstract Rare Isotope Science Project (RISP) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. The RISP driver linac which is used to accelerate the beam, for an example, Uranium ions from 0.3 MeV/u to 200 MeV/u consists of superconducting RF cavities and warm quadrupole magnets for focusing heavy ion beams. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the requirements of dynamic errors and correction schemes to minimize the beam centroid oscillation and preserve beam losses under control.

THPWO065	Optics Design and Correction of High Order Aberration of the Charge Stripper Beam Line of RAON	3906
	H.J. Kim, D. Jeon, H.J. Kim IBS, Daejeon, Republic of Korea J.G. Hwang, E.-S. Kim Kyungpook National University, Daegu, Republic of Korea
	RAON (Rare isotope Accelerator Of Newness) in Korea will be providing the 400 kW of 238U⁷⁹⁺ beam with 8 puA and 200 MeV/u. One of the critical components of this project in the SCL is the design of the charge stripper. Between the two segments of the SCL, the charge stripper strips electrons from ion beams to enhance the acceleration efficiency in the following SCL2. For high efficiency of the acceleration and high power in SCL2, the optimum energy of striped ion in solid carbon foil stripper for SCL1 was estimated by using code LISE. The thickness of the solid carbon foil is 300 ug/m2. Based on this study, the charge stripping efficiency of solid carbon stripper is ~80 %. For the charge selection from ions which produced by the solid carbon stripper, the dispersive section is required in down-stream of the foil. The designed optics for dispersive section is based on the mirror-symmetric optics to minimize the effect of high-order aberration. And the high-order aberration in designed optics was investigated and performed the correction of high-order effect using sextupole magnets.

Paper

Title

Page

Start-to-end Simulations for Heavy-ion Accelerator of RISP

1958

E.-S. Kim, S.W. Jang
KNU, Deagu, Republic of Korea
J. Bahng, J.G. Hwang
Kyungpook National University, Daegu, Republic of Korea
B. Choi, D. Jeon, H.J. Kim, H.J. Kim
IBS, Daejeon, Republic of Korea

RAON has been designed as a facility for rare isotope accelerator at Korea. The aceelerator consists of 28 GHz superconducting ion source, LEBT, RFQ, MEBT, superconducting linac and HEBT. The linac accelerates ion beams to 200 MeV/u with a beam power of 400 kW. Start-to-End simulations are performed from ECR-IS to HEBT and the detailed beam simulation results are presented. The beam dynamics issues are also discussed.

WEPEA032

Estimation and Correction of the Uncontrolled Beam Loss due to the Alignment Error in the Low-energy Linear Accelerator of RAON

2570

J.G. Hwang, E.-S. Kim
Kyungpook National University, Daegu, Republic of Korea
D. Jeon, H.J. Kim
IBS, Daejeon, Republic of Korea

RAON(Rare isotope Accelerator Of Newness) mainly consists of the front-end system, ISOL system , re-accelerator for ISOL system, charge stripper section and main linear accelerator(Linac) for ECR ion source. Since the beam energy at the down-stream of the front-end system is low, 0.3~0.5 MeV/u, the trajectories of the beam is very sensitive the alignment error of the magnets and cavities at the entrance of the main Linac. It can be caused the uncontrolled beam loss due to the large amplitude of the trajectory. The effect of the alignment errors of the magnets and cavities is estimated and corrected by using analytical model which is based on analytical model and code TRACK. The calculation result based on the analytical model agrees very well with the simulation by using the TRACK code. Using the analytical model, the position and number of the corrector and Beam Position Monitor(BPM) in low energy Linac was determined to compensate the amplification of the beam trajectory under 400 um. We will present the result of the estimation of the alignment error and the correction using steering magnet with strip-line Beam Position Monitor (BPM) in a low energy section.

WEPEA033

Optimization of Injector System for Early Commissioning Phase of Compact-ERL.

2573

J.G. Hwang, E.-S. Kim
Kyungpook National University, Daegu, Republic of Korea
T. Miyajima
KEK, Ibaraki, Japan

Injector system of Compact-Energy Recovery Linear accelerator, which is currently develping in Photon Factory of KEK at Japan, consists of the photo-cathode DC gun, two solenoids, a 1.3 GHz buncher ,three 1.3 GHz 2 cell injector cavities, 5 quadrupole magnet and merger section. Target values of beam produced by the injector system are kinetic energy of 5 MeV, the normalized transverse emittance of under 0.1 mm-mrad and the bunch length of under 3 ps with the 7.7 pC charge per bunch and the repetition rate of 1.3 Ghz. In this low energy region, the effect of the space charge is dominated to cause the emittance growth. The optimization is performed by using MOGA (Multi-Object Genetic Algorithm) with code GPT to consider the effect of space charge under optimization. The code General Particle Tracer (GPT) is a 3D Paricle-In-Cell(PIC) code based on multi-layer object-oriented design. Using this method with code GPT, the target values was achieved at the exit of the merger section such as the normalized emittance of 0.1 mm-mrad with bunch length of 3 ps and kinetic energy of 5 MeV.

WEPEA034

Study on the Beam Dynamics in the RISP Driver Linac

2576

H.J. Kim, H.J. Jang, D. Jeon
IBS, Daejeon, Republic of Korea
J.G. Hwang
Kyungpook National University, Daegu, Republic of Korea
E.-S. Kim
KNU, Deagu, Republic of Korea

Abstract Rare Isotope Science Project (RISP) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. The RISP driver linac which is used to accelerate the beam, for an example, Uranium ions from 0.3 MeV/u to 200 MeV/u consists of superconducting RF cavities and warm quadrupole magnets for focusing heavy ion beams. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the requirements of dynamic errors and correction schemes to minimize the beam centroid oscillation and preserve beam losses under control.

THPWO065

Optics Design and Correction of High Order Aberration of the Charge Stripper Beam Line of RAON

3906

H.J. Kim, D. Jeon, H.J. Kim
IBS, Daejeon, Republic of Korea
J.G. Hwang, E.-S. Kim
Kyungpook National University, Daegu, Republic of Korea

RAON (Rare isotope Accelerator Of Newness) in Korea will be providing the 400 kW of 238U⁷⁹⁺ beam with 8 puA and 200 MeV/u. One of the critical components of this project in the SCL is the design of the charge stripper. Between the two segments of the SCL, the charge stripper strips electrons from ion beams to enhance the acceleration efficiency in the following SCL2. For high efficiency of the acceleration and high power in SCL2, the optimum energy of striped ion in solid carbon foil stripper for SCL1 was estimated by using code LISE. The thickness of the solid carbon foil is 300 ug/m2. Based on this study, the charge stripping efficiency of solid carbon stripper is ~80 %. For the charge selection from ions which produced by the solid carbon stripper, the dispersive section is required in down-stream of the foil. The designed optics for dispersive section is based on the mirror-symmetric optics to minimize the effect of high-order aberration. And the high-order aberration in designed optics was investigated and performed the correction of high-order effect using sextupole magnets.