Design of a symmetry in-flight separator optics for medium

heavy-ion beamsHwang Ji-Gwang, Noh Seon-Yeong, Kim Eun-San

Accelerator Physics Laboratory, Kyungpook National University

Hatanaka Kichiji

Research Center for Nuclear Physics, Osaka University

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Contents

• Introduction to accelerator laboratory in KNU

• Layout & feature of in-flight separator

• Degrader optimization in LISE++

• RI beam separation simulation in LISE++

• Beam profile after separation

• 2nd order effect in beam separator

• 3rd order effect in beam separator

• High order effect correction by sextupole

• Summary

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경북대 가속기 물리 연구실(~15 명: 대학원생, 박사연구원, 연구교수)

4세대 방사광 가속기 공동연구 (미국 LBNL)- 초젂도 선형가속기 빔 물리연구- HHG-Seeded X-ray FEL 설계연구

빔 진단 장치 개발 공동연구 (일본 KEK) –FEL 및 ILC 용- Cavity-type BPM 개발 (C-band / L-Band / S-band BPM): 설계 / 제작 / 빔 테스트 / 빔 궤도 최적화 연구

중입자 가속기 공동연구 ( 부산 기장 )- In-flight 빔 라인설계 (2차 희귀 동위원소 분리기)

Past-R&D (국내 가속기)- 10 GeV FEL 설계 참여 (포항가속기)- 3 GeV 저장링 설계 참여(포항가속기)- 등등

Layout & feature of in-flight separator

Maximum rigidity: 9 Tm

Energy acceptance: ±4%

Angular acceptance : θ= ± 20 mrad

Φ= ± 35 mrad

Energy degrader : Uniform thickness

Energy dispersion: 1.5448 m

Mass dispersion: -0.90818 m

E/ΔE (x0=2.36 mm): 180

(d/R=0.5; without energy straggling)

A/ΔA (x0=2.36 mm): 128

(d/R=0.5; without energy straggling)

Path length : 24.183m

Beryllium Target

TripletAluminum Degrader

Focal point-1

Sector

Primary beam( 12C6+, 430MeV)

9Li3+

200MeV/u

Degrader optimization in LISE++

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IPPIr WIPWPWICombined PIIP )(10log10

Slit

Slit

Beam separation using by LISE++

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Beam separation at the F1

Beam separation at the F2

Yield of the 9Li at the F2 has 400 times larger than yield of 8Li.

Yield of 9Li: 4.58 X 106 pps (=0.732 ppA)(when the primary beam 12C has 50 pnA)

Transmission rate : 7.32%

Beam profile at the exit of separator

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9Li 8Li8He

The high order effect by magnets

• The transfer matrix of degrader, bending magnet and quadrupole has higher order terms.

where Rij,Tijk , Uijkl is the first, second, third order transfer matrix of each element, respectively.

• The 2nd and 3rd order effect could be corrected by sextupole and octupole, respectively.

j jk jkl

lkjijklkjijkjiji XXXUXXTXRX 0000001

Up to 2nd order effect in beam separator

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The effect of the 2nd order aberration could be compensate by slit at the F1.

The 2nd order effect of magnets and degrader cause the beam size growth at the F2.

Sllit

Up to 3rd order effect in beam separator

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Focusing problem(→Large beam size)

Sllit

s [mm]

Correction of the high order effect

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Beryllium Target

Triplet

Aluminum DegraderFocal point-1

Sector

Primary beam( 12C6+, 430MeV)

Focusing was improved

Feature of designed beam line

Beryllium Target (9.9cm)

12C6+ (430MeV/u)

9Li3+, 200MeV/u

Primary beam: 12C6+ (430MeV/u)Secondary beam: 9Li3+ (200MeV/u)Energy acceptance: ±4%Angular acceptance : ± 20 mrad, ± 35 mradEnergy degrader : Uniform thickness (d/R=0.53)Energy dispersion: 1.5448 m Mass dispersion: -0.90818 mE/ΔE (x0=2.36mm): 180(d/R=0.5; without energy straggling)A/ΔA (x0=2.36mm): 128(d/R=0.5; without energy straggling)Path length : 24.183m

Summary

• We perform the beam separation simulation on the in-flight separator for Gi-Jang Heavy-ion accelerator.

• The optimum wedge thickness was selected.

• In-flight separator has 40mrad of horizontal angular acceptance, 70mrad of vertical angular acceptance, 8% of energy acceptance with d/R=0.53 aluminum homogeneous degrader.

• The high order effect in the in-flight separator was investigated and corrected by three sextupole.(The focusing at the F2 was improved)

• Effect of the up to 7 high order will be study.

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