Accelerator-based epithermal neutron source for BNCT using thin-layer solid-Lithium target Cancer Intelligence Care Systems, Inc, 2014 1 a† Cancer Intelligence

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


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


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.



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.


- 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


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


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



-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


Does lithium-target explode sure enough?

No worries !!!


Thin-layer solid Li-target

Total amount of Lithium <0.5g


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


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


　 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


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


Evaluation of Lithium Target System 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 calculated by PHITS 2.16

ModeratorModerator

ReflectorReflector

VTSMVTSM

Gate ValveGate Valve

Beam TubeBeam Tube

TargetTarget

Lithium Recovery System


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.


On behalf of many collaborators.Thank you very much for your attention!

Documents

Accelerator-based epithermal neutron source for BNCT using thin-layer solid-Lithium target Cancer Intelligence Care Systems, Inc, 2014 1 a† Cancer Intelligence