Improvement of beam current in KIRAMS-13 using upgrade of ion source system Hong Jin Lee, W.K Lee, J.H Park, B.C Lee, I.W Lee Cyclotron center Department of Nuclear Medicine Seoul National University Bundang Hospital

CONTENTS CYCLOTRON SNUBH KIRAMS -13 SNUBH KIRAMS -13 OF UPGRADE RESULTS & CONCLUSION

Ⅰ. CYCLOTRON Particle accelerator for nuclear reaction First developed by Lawrence, USA, 1932 Produce positron emission radio isotopes (11C, 13N , 15 O,18 F) KIRAMS-13 (Accelerate Hydrogen Ion (H-) up to 13 MeV)

Profile of Cyclotron working H+ H- Carbon (stripper) foils 2e- Extraction System 18F- Ion Source H-

Cyclotron Main Structure and Function - Ion Source : Generate hydrogen Ion (H- ) - Magnet : Make hydrogen ion bend - RF System : Accelerate charged particle (A/C. sign wave 77.3MHz) in electro-field Beam Extraction : Extract protons by carbon foil Target : Bombardment (protons collide target material) Others Cooling System Vacuum System

Ion source system Hydrogen ion (H-) Injection of hydrogen gas into Ion plasma column Generating hydrogen ion (plasma) under high Arc Exhausting H- ion only through anode slit Chimney H2 gas

II. KIRAMS -13 Capacity Model KIRAMS-13 GE PETtrace IBA 18/9 Cyclotron SIMENCE Eclipse HP Energy [Mev] 12.5 16.5 18 11 18F- [mCi/Hr] 900~1,000 5,000 8,000 2,500 Average Beam Current Proton: 30uA Proton: 80uA Deutron: 60uA Proton: >100uA Deutron: 35uA Proton: 60uA Target F-18 C-11 F-18, C-11 N-13, O-15

ⅡI. SNUBH KIRAMS -13 UPGRADE Upgrade of Ion Source Factors Chimney Internal Diameter Chimney Slit Length Change of Hydrogen Gas Inlet Position Chimney H2 gas

1. Chimney internal diameter Condition RF = 60% , Gas = 5 sccm , ARC = 1.2 A Chimney (Internal diameter) 6.3 6.5 6.8 7.0 7.5 8.0 9.0 Beam Current (uA) 38 40 42 45 50 49  The best internal diameter in chimney was 8.0

2. Chimney slit length 기존 0.6 x 4mm Condition RF = 60% , Gas = 5 sccm , ARC = 1.2 A Chimney (Slit Length) 4 5 3 Beam Current (uA) 40 35 These results were demonstrated under chimney internal diameter 6.8 The slit length was not dependent on increasing beam current

3. Change of hydrogen gas injection position H2 gas H2 gas Chimney

Lower Both Upper Condition RF = 80% , Gas = 6 sccm , ARC = 2.2 A Hydrogen Gas Inlet Position Condition RF = 80% , Gas = 6 sccm , ARC = 2.2 A Gas Inlet Lower Upper Both Beam Current Max. (uA) 88 91 90  Beam current was dependent on gas inlet position (Upper > Both > Lower)

Life cycle of cathode Lower Both Upper Condition Hydrogen Gas Inlet Position Condition RF = 70% , Gas = 4 sccm , ARC = 1.8 A Gas Inlet Lower Upper Both Cathode Life Cycle (# of irradiation) 50 ± 6 In testing 90 ± 5

III. Upgrade of KIRAMS -13 Model KIRAMS-13 After upgrade GE PETtrace IBA 18/9 Cyclotron SIMENCE Eclipse HP Energy [Mev] 12.5 16.5 18 11 18F- [mCi/Hr] 900~1,000 2,300~2,500 5,000 8,000 2,500 Average Beam Current Proton: 30uA Proton: 70uA Proton: 80uA Deutron: 60uA Proton: >100uA Deutron: 35uA Proton: 60uA Target F-18 C-11 F-18, C-11 N-13, O-15

Ⅳ .RESULTS Irradiation for 90 min Before upgrade After upgrade Cyclotron operating condition: Duty = 80%, Gas = 5 sccm, ARC = 2.0 A Irradiation for 90 min Before upgrade After upgrade Beam Current 50 uA 70 uA F-18 Production 2,000~2,300 mCi 3,400~3,800 mCi

 June/2008 ~ Feb/2009: Overall 96% The Monthly Rate of KIRAMS operation in SNUBH Month % 2008 2009 Mon Real Total % 6 38 39 97 1 35 92 7 40 46 87 2 42 100 8 9 10 41 98 11 12 44 95 6 7 8 9 10 11 12 1 2 The monthly rate of KIRAMS-13 operation = (the number of real operating / the number of total operation) *100  June/2008 ~ Feb/2009: Overall 96%

CONCLUSION Upgrade of F-18 target : 3,500~4,000 mCi/h After upgrade of ion source parts in KIRAMS-13, the beam current and F-18 production was increase and stable F-18 Production / Hr (mCi/hr) ; Before: 900~1,000 mCi/hr After upgrade: 2,300~2,500 mCi/hr Upgrade of F-18 target : 3,500~4,000 mCi/h

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