1. Accelerator-based epithermal neutron source for BNCT using thin-layer solid-Lithium target
Yoshio Imahori a*, Ryo Fujii a, Masaru Nakamura a, and Jun Itami b
a†Cancer Intelligence Care Systems, Inc., Ariake 3-5-7, Koutou-ku, Tokyo,
Japan
b National Cancer Center, Tsukiji 5-1-1, Chuo-ku, Tokyo,
Japan
Cancer Intelligence Care Systems, Inc, 2014

2. Cancer Intelligence Care Systems, Inc., 2014
NCC- CICS - AccSys
"Optimization of matching in the major components
of the accelerator neutron source for BNCT“ in Dec-2012
National Cancer Center Japan
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
CICS, Inc.
AccSys Technology
HITACHI
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
Cancer Intelligence Care Systems, Inc., 2014

3. Location of National Cancer Center in Tokyo
National Cancer Center Japan
Cancer Intelligence Care Systems, Inc., 2014

4. NCC: New Facility for Accelerator based BNCT
New building for BNCT
Radiation shield in BNCT room
B-1
Cancer Intelligence Care Systems, Inc, 2014

5. Cancer Intelligence Care Systems, Inc, 2014
(Radiation Shield)
6.5 m
1000kg
(RFQ Linac)
1.7m
6.0 m
10t
(Radiation Shield)
5t (Beam Shaping Assembly)
8.8 m
Cancer Intelligence Care Systems, Inc, 2014

6. High Current Proton RFQ Linac
Injector
RFQ Linac
Q-Mag.
Bending Mag.
Specification
・Particle
Proton
Steering Mag.
・Beam Energy
2.5 MeV
・Beam Current
20 mA (CW)
・Ion Source
Microwave Ion Source
・LEBT
Solenoid
・Accelerator
RFQ
BPM
・RF
Klystron (330kW CW, 400MHz)
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7. Whole picture of high current Linac for BNCT

8. Proton accelerator with RFQ type

9. The record of 2.46MeV and 10mA is attained.
Cancer Intelligence Care Systems, Inc., 2014

10. Cancer Intelligence Care Systems, Inc., 2014
A design and the strategy for the solid 7Li-target device
Metal lithium is suitable for 7Li(p,n) 7Be reaction in low Ep.
Ep=2.5MeV makes it possible 7Li thin-layer within 100μm in a case of vertical bombardment.
The thin-layer permits high heat conduction. Heat conductivity is inverse proportion to the distance of heat movement. Thus 50μm thickness of Li becomes 40 times more heat conductive than that of 5 mm of Be.
7Li contaminated with 7Be can be easily removed by chemical reaction and can be transported to a distant area from patient and medical staff.
Low energy neutrons max En=0.6MeV can be obtained by 2.5MeV Ep and Li-target, resulting that slowdown of 1 to 60th permits to reduce neutron energy to <10keV.
Cancer Intelligence Care Systems, Inc., 2014

11. Cancer Intelligence Care Systems, Inc, 2014
7Be contamination and Li-target cleansing
- Radioactivity with side nuclear reactions -
Cancer Intelligence Care Systems, Inc, 2014

12. Handling of 7Be in compliance with the regulations
7Li(p,n)7Be
Proton Beam
半減期：53.29day
T1/2
Accumulation
Drainage
Processing 洗浄
Wash out
貯留槽へ移送
Transfer to
reservoir tank
貯留槽
（21ヶ月間貯留）
Accumulation
for 24 month
減衰保管
（21ヶ月間）
Storage for decay
for 24 month
Transfer to main tank
Drainage after dilution
Cancer Intelligence Care Systems, Inc, 2014

13. Cancer Intelligence Care Systems, Inc, 2014
In situ neclear reaction in Li-6 metal (7.5%)
Production of 3H
Neutron Energy
Cross Section
Thermal flux
Saturation Yield
(eV)
(cm2) （
n/cm2/s ）
3H (n/s = Bq)
940
1.555E+09
4.085E+07
1480
2.900E+08
1.200E+07
2122
9.217E+07
5.466E+06
4740
2.813E+06
3.726E+05
6700
7.149E+05
1.339E+05
Total 3H
1.941E+09
5.882E+07
3H half life
hour
Accumulation per 1 hr
3.774E+02 Bq
per 8 hr
1.875E+03
7.547E+03
（8hr×25days）
1.614E+07
3.096E+07
2.940E+07
1.59 mCi
per 25 day
per 1 year
Per 2year
Continuous for 12.3yeras
Using 99.99% of Li-7 metal makes 3-order down.
< 1.6μCi
Cancer Intelligence Care Systems, Inc, 2014

14. Equipments for Li-deposit test
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15. Lithium deposit test on the sham glass target
Correlation of Li deposit profile between estimation and measurement
Estimation
Measurement
Time-dependent and formula-dependent deposit of thin-layer Li ⇒　 possible to make the surface flat
Cancer Intelligence Care Systems, Inc, 2014

16. Does lithium-target explode sure enough? No worries !!!
Thin-layer solid Li-target
Total amount of Lithium <0.5g
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Cancer Intelligence Care Systems, Inc, 2014 16

17. Cancer Intelligence Care Systems, Inc, 2014
Fourier's Law and boiling curves
q = α⊿T
Log q
CHF point　⇒
The domain where nucleate boiling is dominant
Uncontrollable by the flow velocity ⇒
The forced convection is dominant　⇒
(1) Flow velocity ⇒ up
(2) Heat flux ⇒ down
Flow velocity
Log⊿T
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18. Cancer Intelligence Care Systems, Inc., 2014
Flow velocity ⇒ up
Required cooling-water conditions
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19. Cancer Intelligence Care Systems, Inc, 2014
Heat flux ⇒ down
Optimization of target-base and its design
Form change + beam irradiation conditions
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 15
Heat transfer suface(%)
100
117
134
185
213
265
238
144
192
129
115
166
193
162
178
Flow verocity (%) 98
102
111 67
143 95
116
107
max Temparture (℃)
153
135
128
123
120
119
142
141
122
138
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
trench width
trench depth
number of trench
spiral pitch length
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20. Target Cooling System: 8-inlet manifolds
Flow rate(L/min)
Pressure (MPa)
Measu.
Measu.
Total
Average
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21. Cancer Intelligence Care Systems, Inc., 2014
Evaluation of Lithium Target System　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　
calculated by PHITS 2.16
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22. Lithium Recovery System
Moderator
Reflector
VTSM
Gate Valve
Beam Tube
Target

23. Cancer Intelligence Care Systems, Inc, 2014
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 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. Cancer Intelligence Care Systems, Inc, 2014
On behalf of many collaborators. Thank you very much for your attention!
Cancer Intelligence Care Systems, Inc, 2014