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Accelerator-based epithermal neutron source for BNCT using thin-layer solid-Lithium target
Cancer Intelligence Care Systems, Inc, 2014 1
a†Cancer Intelligence Care Systems, Inc., Ariake 3-5-7, Koutou-ku, Tokyo,135-0063 Japan
b National Cancer Center, Tsukiji 5-1-1, Chuo-ku, Tokyo,104-0045 Japan
Yoshio Imahori a, Ryo Fujii a, Masaru Nakamura a, and Jun Itami b
2 Cancer Intelligence Care Systems, Inc., 2014
National Cancer Center Japan
CICS, Inc. AccSys Technology
NCC – CICS"Establishment of the standard of boron neutron capture therapy (BNCT) using an accelerator" in Dec 2010
CICS-AccSys“Towards utilization of hospital based-type BNCT" in Sep 2012
NCC- CICS - AccSys "Optimization of matching in the major components of the accelerator neutron source for BNCT“ in Dec-2012
1 Moriya Cutlery Laboratory, Ltd.2 Shimane Institute for Industrial Technology,
3 Tanaka Kikinzoku Kogyo K.K.4 Nippon light Metal Co., Ltd.5 Fujidenolo Co. Ltd.6 AdIn Research,Inc.7 Showa Shinku Co., Ltd.
8 TOYAMA, Inc.
Medical-engineering collaboration research in many fields
HITACHI
Cancer Intelligence Care Systems, Inc., 2014 3
Location of National Cancer Center in Tokyo
National Cancer Center JapanNational Cancer Center Japan
NCC: New Facility for Accelerator based BNCT
Cancer Intelligence Care Systems, Inc, 2014 4
Radiation shield in BNCT roomRadiation shield in BNCT room
New building for BNCTNew building for BNCT
B-1B-1
Cancer Intelligence Care Systems, Inc, 2014
5
22.5 m
6.5 m6.0 m
8.8 m
1000kg(RFQ Linac)
10t (Radiation Shield)
10t (Radiation Shield)
1.7m1.7m
5t (Beam Shaping Assembly)
High Current Proton RFQ Linac
Cancer Intelligence Care Systems, Inc, 2014 6
RFQ LinacInjector
Q-Mag. Bending Mag.
Steering Mag.
BPM
Specification
・ Particle
・ Beam Energy
・ Beam Current
・ Ion Source
・ LEBT
・ Accelerator
・ RF
Proton
2.5 MeV
20 mA (CW)
Microwave Ion Source
Solenoid
RFQ
Klystron (330kW CW, 400MHz)
Whole picture of high current Linac for BNCT Whole picture of high current Linac for BNCT
Proton accelerator with RFQ typeProton accelerator with RFQ type
The record of 2.46MeV and 10mA is attained.
Cancer Intelligence Care Systems, Inc., 2014 9
Cancer Intelligence Care Systems, Inc., 2014 10
A design and the strategy for the solid A design and the strategy for the solid 77Li-Li-target device target device
1.1. Metal Metal lithiumlithium is is suitable for for 77Li(p,n)Li(p,n) 7 7Be reaction Be reaction in low Epin low Ep..2.2. Ep=2.5MeV makes it possible Ep=2.5MeV makes it possible 77Li thin-layer within 100μm in a Li thin-layer within 100μm in a
case of vertical bombardment.case of vertical bombardment.3.3. The thin-layer permits high heat conduction. The thin-layer permits high heat conduction. Heat conductivity Heat conductivity
is inverse proportion to the distanceis inverse proportion to the distance of heat movement. Thus of heat movement. Thus 50μm thickness of Li becomes 40 times more heat conductive 50μm thickness of Li becomes 40 times more heat conductive than that of 5 mm of Be. than that of 5 mm of Be.
4.4. 77Li contaminated with Li contaminated with 77Be can be easily removed by chemical Be can be easily removed by chemical reactionreaction and can be transported to a distant area from patient and can be transported to a distant area from patient and medical staff.and medical staff.
5.5. Low energy neutrons max En=0.6MeV can be obtained by Low energy neutrons max En=0.6MeV can be obtained by 2.5MeV Ep and Li-target, resulting that slowdown of 1 to 60th 2.5MeV Ep and Li-target, resulting that slowdown of 1 to 60th permits to reduce neutron energy to <10keV. permits to reduce neutron energy to <10keV.
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- Radioactivity with side nuclear reactions -
7Be contamination and Li-target cleansing
Be-7 Saturation Yield 16.49 TBq RadioActivity per Month 1.22 TBq Dose Ratio(1.22TBq) 2.05 mSv/h
Cu-64 Saturation Yield 305.60 MBq RadioActivity 147.90 MBq Maximum radioactivity in case of full time operation.
Dose Ratio(147.9MBq) 0.77 mSv/h
H-3 Saturation Yield 58.82 MBq RadioActivity per Month 0.015 MBq Dose Ratio - mSv/h
Ar-41 Concentration of Argon in air 9.60E-03 Bq/cm3
Maximum permissible concentration in air 1.00E-01 Bq/cm3
Ratio 0.096 ( < 1 )
[ 7Li (p , n) 7Be ]
[ 63Cu (n , γ) 64Cu ]
[ 40Ar (n , γ) 41Ar ]
[ 6Li (p , t) 4He ]
T(1/2) = 53.29 d
T(1/2) = 12.7 h
T(1/2) = 12.33 y
T(1/2) = 1.822 h
Handling of 7Be in compliance with the regulations
Cancer Intelligence Care Systems, Inc, 2014 12
7Li(p,n)7BeProton BeamProton Beam
洗浄
貯留槽へ移送
貯留槽( 21 ヶ月間貯留)
減衰保管( 21 ヶ月間)
Transfer to main tank
Drainage after dilution
Accumulation
半 減 期 :53.29day
Drainage
Processing
T1/2
Wash out
Transfer to reservoir tank
Accumulationfor 24 month
Storage for decayfor 24 month
Cancer Intelligence Care Systems, Inc, 2014 13
1.59 mCi1.59 mCi
Production of 3H
Neutron Energy Cross Section Thermal flux Saturation Yield
(eV) (cm2) (n/cm2/s) 3H (n/s = Bq)
0.025-0.01 940 1.555E+09 4.085E+07
0.01-0.005 1480 2.900E+08 1.200E+07
0.005-0.001 2122 9.217E+07 5.466E+06
0.001-0.0005 4740 2.813E+06 3.726E+05
0.0005- 6700 7.149E+05 1.339E+05
Total 3H 1.941E+09 5.882E+07
3H half life 108010.8 hour Accumulation per 1 hr 3.774E+02 Bq
per 8 hr 1.875E+03 Bq
7.547E+03 Bq ( 8hr×25days )1.614E+07 Bq
3.096E+07 Bq
2.940E+07 Bq
In situ In situ neclear reaction in Li-6 metal (7.5%) neclear reaction in Li-6 metal (7.5%)
per 25 dayper 1 year
Per 2year
Continuous for 12.3yeras
< 1.6μCiUsing 99.99% of Li-7 metal makes 3-order down.
Equipments for Li-deposit test
Cancer Intelligence Care Systems, Inc, 2014 14
Cancer Intelligence Care Systems, Inc, 2014 15
-20
-10
0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60 70 80
20min
計算値
-20
-10
0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60 70 80
15min
計算値
-20
-10
0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60 70 80
10min
計算値
EstimationMeasurement
Correlation of Li deposit profile between estimation and measurement
Time-dependent and formula-dependent deposit of thin-layer Li ⇒ possible to make the surface flat
Lithium deposit test on the sham glass target
Cancer Intelligence Care Systems, Inc, 2014 16
Does lithium-target explode sure enough?
No worries !!!
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Thin-layer solid Li-target
Total amount of Lithium <0.5g
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Flow velocity
Log⊿T
CHF point ⇒
Log q
The forced convection is dominant ⇒
The domain where nucleate boiling is dominant
Uncontrollable by the flow velocity ⇒
Fourier's Law and boiling curves
(2) Heat flux ⇒ down
(1) Flow velocity ⇒ up
q = α⊿T
Flow velocity ⇒ up
Cancer Intelligence Care Systems, Inc., 2014 18
35000
45000
55000
65000
75000
85000
0 50 100 150 200 250 300
Rem
oved Heat P
ower (W
)
Cooling Water (L/min)
Lithium Target Heat Removal Analysis
160(L/min)
0
0.5
1
1.5
2
2.5
0 50 100 150 200 250 300 350P
ress
ure
(Mpa
)
Flow rate (L/min)
Flow-Pressure Curve
Required cooling-water conditions
Cancer Intelligence Care Systems, Inc, 2014 19
original case 1 case 2 case 3 case 4 case 5 case 6 case 7 case 8 case 9 case 10 case 11 case 12 case 13 case 14 case 15Heat transfer suface(%)
100 117 134 185 213 265 238 144 192 129 115 166 193 162 185 178
Flow verocity (%) 100 98 102 100 100 100 111 100 67 143 111 111 95 116 102 107max Temparture (℃)
153 135 128 123 120 119 117 142 141 122 138 129 131 128 131 130
Pressure drop (MPs)
0.89 2.05 1.54 10.9 1.18 1.44 1.69 1.2 0.91 1.67 1.1 1.55 1.39 1.68 1.7 1.76
Optimization of target-base and its design
Form change + beam irradiation conditions
trench widthtrench widthtrench depthtrench depthnumber of trenchnumber of trench
spiral pitch lengthspiral pitch length
Heat flux ⇒ down
Target Cooling System: 8-inlet manifolds
Cancer Intelligence Care Systems, Inc., 2014 20
No. 表示値 No. 表示値
FL1 35.4 PS1 1.33
FL2 34.5 PS2 1.3
FL3 36.2 PS3 1.3
FL4 36.2 PS4 1.29
FL5 34.7 PS5 1.36
FL6 34.3 PS6 1.36
FL7 35.9 PS7 1.38
FL8 35.2 PS8 1.35
合計 282.4 平均 1.33
(L/min)流量計 (MPa)圧力計Flow rate(L/min) Pressure (MPa)
Measu.Measu.
Total Average
Cancer Intelligence Care Systems, Inc., 2014 21
Evaluation of Lithium Target System calculated by PHITS 2.16
ModeratorModerator
ReflectorReflector
VTSMVTSM
Gate ValveGate Valve
Beam TubeBeam Tube
TargetTarget
Lithium Recovery System
Cancer Intelligence Care Systems, Inc, 2014 23
Conclusion
• Combination of low-energy proton beam 2.5MeV and Li-target is feasible, and each elements are going toward safety-alliance based on a basic design for the solid 7Li-target device.
• We should follow IAEA-TECDOC-1223 (May 2001) “Current Status of neutron capture therapy”, in which the definition of epi-thermal neutron < 10KeV can be accomplished by using the 2.5MeV of low-energy proton beam with 20mA.
• 7Be (half life 53.12 days) produced in the Li target should be disposed protectively, thus we can perform ABENS-BNCT safely.
• This new machine and building are completed to Summer 2014 in NCC in Tokyo.
Cancer Intelligence Care Systems, Inc, 2014 24
On behalf of many collaborators.Thank you very much for your attention!
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