progress on transmutation experiments induced by d2 gas ... · progress on transmutation...

Progress on Transmutation Experiments

induced by D2 gas permeation

T.Itoh1,2, J. Kasagi1, Y.Iwamura1, S.Tsuruga3

1Condensed Matter Nuclear Reaction Division, Research Center for Electron

Photon Science, Tohoku University, Sendai 982-0826, Japan 2CLEAN PLANET Inc., Tokyo 105-0022, Japan 3 Research & Innovation Center, Mitsubishi Heavy Industries, Ltd., Yokohama 236-8515, Japan

12th International Workshop on Anomalies in Hydrogen Loaded Metals

1

Cs → Pr Transmutation MHI Experiments

Pr141

59

133

55Cs

J. J. App. Phys. 41(2002)4642 2

Replicated experiment of Toyota lab

D2 permeation

No

Cs, o

nly

Mu

ltila

ye

r

No

Cs, N

o M

ultila

ye

r

Cs implanted

Multilayer

Hioki et al. JJAP 52 (2013) 107301 3

There is a criticism that the mass of the nucleus was not

identified, since the employed mass spectrometry, such as ICP-

MS, cannot exclude possibilities of chemical compound objects.

Direct assignment of the nucleus (141Pr) by using nuclear

physics approach is highly demanded.

Successive various measurements showed existencs of 141Pr

XPS, ICP-MS, Tof-SIMS, In-situ XRF at SPring8

Object

Therefore, we employed the Rutherford Backscattering

Spectroscopy (RBS) to identify 141Pr for direct nuclear mass

assignment. 4

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

650 850 1050 1250 1450

7007+7008

X

dY ∝ ρTNb(ds/dW)(x) dx

= ρTNb(ds/dW)(E) (dE/dx)-1dE

dY1/dE

dY2/dE

dY1/dY2 ~ (ρ1/ρ2) (Z1/Z2)2

Distributed near surface

Scattered by Nucleus; Mass determined by kinematics

Advantage for large A and Z

Pd density：6.8×1022 atoms/cm3

(ZPｄ/ZW)2 = (46/74)2 = 0.386

W is more sensitive than Pd by 2.6 times

W density：～5.4×1020 atoms/cm3

Example: Compare W on surface / Pd

Rutherford Backward Scattering（RBS）

x

Pd base Surface Elements

40Ar, 128MeV

5

Expected RBS Spectrum by irradiation 128-MeV 40Ar

102

103

104

10

1

105

106

0 10 20 30 40 50 60 Energy (MeV)

Co

un

t [co

un

t/1

00

ke

v]

(1) Pt impurity in thick Pd :100 ppm

(2)133Cs:uniformly distributed in 0 - 20 nm depth; 200ng/cm2

(3)141Pr: uniformly distributed in 0 - 10 nm depth; 60 ng/cm2 30 ng/cm2 15 ng/cm2

60 ng/cm2

30 ng/cm2

15 ng/cm2

6

Cs transmutation sample by D2 gas Permeation

D2

Sample for RBS was provided by MHI

900℃ 10H Annealing

under Vacuum Condition

Washing a Pd Sample

with Acetone

Washing the Sample with

Aqua Regia

Fabrication Pd-CaO

Multilayer using Ion Beam

Spattering

Cs Deposition

D2 Gas permeation

7

ECR ion source + 930 AVF Cyclotron

Large Scattering chamber

Cyclotron Radioisotpe Center, Tohoku University

8

Geometric Arrangement of Beam, Target and detector

40Ar7+ 128MeV

Target

Detector(Si) Beam: 40Ar7+ 128MeV ～ 1 particle nA Si detector: 300 m in thickness 300 mm2x3, 450 mm2x2

= 165° total = 0.083 sr

Several-hour measurement for a sample to identify Pr of 10 ng/cm2

9

Sensitivity of Pr identification

RBS spectrum Pr-implanted Pd/CaO foil

Implanted：23.4 ng/cm2

Measured：18.9±4.8 ng/cm2

Reproduced well !!

Pt BG: ~ 95 ppm of Pd

By measuring several hours,10 ng/cm2-Pr can be detected with

the confidence level of 99% (or statitical significance of 2.6σ).

Pr

＊test peace was provided by Toyota Central Research and Development Laboratories 10

Sample Target

Am

ZnSe

Au

Au(10nm)/Si

Au

Pt

Pd

test peace

Pr Implantation 1014

Pr:23.4ng/cm２

Ref Sample

(Only Multilayer)

test peace

Cs Implantation

FG sample（SK137）


Ref Sample

(Cs Dope,

No D2 Permeation)


Cs:134ng/cm２

Pr:74ng/cm２

Cs: 94.6 ng/cm2

Pr: 51 ng/cm2

Cs: 57.7 ng/cm2

Pr: 50.8 ng/cm2

11

RBS spectrum：with D2 gas permeation Summed spectrum of foreground samples

0 10 20 30 40 50 60 Energy (MeV)

102

103

104

10

1

105

106

Co

un

t [co

un

t/1

00

ke

v]

Thick Pd

141Pr natW

A=192

W→Pt ??

~1/5000

100 ppm Pt

133Cs

BG: mainly Pt impurity in thick Pd ～100 ppm→BG determine a detection limit. 133Cs：distributed 0 - 80 nm in depth natW: distributed 0 - 80 nm in depth contamination of W（182,183,184,186) of multilayer

(1) A tiny peak at A=141 (141Pr)

141Pr exists on the surface. not observed for without D2 consistent with MHI

report

(2) Pt region: peak structure Pt impurity in Pd in surface layer? W → Pt ? 12


0 10 20 30 40 50 60 Energy (MeV)

102

103

104

10

1

105

106

Co

un

t [co

un

t/1

00

ke

v]

Thick Pd

141Pr natW

A=192

W→Pt ??

~1/5000

100 ppm Pt

133Cs




report

(2) Pt region: peak structure Pt impurity in Pd in surface layer? W → Pt ?

(1)

13

RBS spectrum with D2 gas permeation: Cs, Pr

detection

10-1

102

103

104

10

1

0 10 20 30 40 50 60

Energy (MeV)

Pd

Cs

Pr

Pt

Sample name：SK132

Co

un

t [

co

un

t/2

00ke

v]

0

10

20

30

40

30 32 34 36 38 40 42 44 46 48 50

Energy [MeV]

Pt(BG)

Sample Name:SK130

Exp.

Pt (BG)

fit

30 32 34 36 38 40 42 44 46 48 50

Cou

nt [

co

un

t/2

00ke

v]

Energy [MeV]

0

10

20

30

40

Sample Name:SK132 Exp.

Pt (BG)

fit

Count

[count/100kev]

14

Pr amount comparison of ICP-MS and RBS

Sample Name Analytical method Cs(ng/cm2) Pr(ng/cm2)

SK130 ICP-MS 57.7 50.8

RBS 94.1±10.9 < 6

SK132 ICP-MS 94.6 51

RBS 37.8±5.9 < 5.1±2.6

SK137 ICP-MS 134 74

RBS 19.7±7.8 < 11

Pr test Sample Pr Implanted 23.4

RBS 19±5

Comparing between the results of ICP-Ms and RBS,

quantitative agreement is not good.

Y(RBS)/Y(ICP) = 0.15 ~ 1.63 for 133Cs

< 0.15 for 141Pr

→ Measurement points of ICP-MS and RBS are different？

→ may be due to the local distribution of 141Pr

15

Non-uniform distribution of Pr (XRF @ SPring-

8)

0

200

400

600

800

1000

1200

3.5 4 4.5 5 5.5

Energy(keV)

Counts

Point 4-4 (Much Pr detection)

Point 3-4(Pr detection)

Point 6-4(No Pr)

Cs

Pr4X1014/cm2

1X1014/cm2

0

200

400

600

800

1000

1200

3.5 4 4.5 5 5.5

Energy(keV)

Counts



Point 6-4(No Pr)



Point 6-4(No Pr)

Cs

Pr4X1014/cm2

1X1014/cm2

100 micron beam;SP-24, 13-4

6

5

4

3

2

1

654321

6

5

4

3

2

1

654321X

Y

100μ m

100μ m

Much Pr detection

Pr detection

No Pr

13-4

XRF study shows: Existing probability of Pr strongly depends on location

Average value of Pr in 13-4 4.4×1013 atoms/cm2

Y. Iwamura et al., Condensed Matter Nuclear Science, World Scientific, New Jersey, p.178, 2006. 16


0 10 20 30 40 50 60 Energy (MeV)

102

103

104

10

1

105

106

Co

un

t [co

un

t/1

00

ke

v]

Thick Pd

141Pr natW

A=192

W→Pt ??

~1/5000

100 ppm Pt

133Cs




report

(2) Pt region: peak structure Pt impurity in Pd in surface layer? W → Pt ?

(2)

17

W & Pt in Pd-CaO Multilayer

Pd Substrate

Target (Pd,CaO)

Ar Ion (1kV15〜20mA)

W Filament ●Pd（multilayer＆Substrate)

contain Pt about 100ppm ●Pd-CaO multiLayer contain

W from ion source

CaO(２nm)

CaO(2nm)

CaO(２nm)

CaO(２nm)

CaO(２nm)

Pd(40nm)

Pd(20nm)

Pd(20nm)

Pd(20nm)

Pd(20nm)

Pd

100μm

Ion beam Sputtering Apparatus

18


0 10 20 30 40 50 60 Energy (MeV)

102

103

104

10

1

105

106

Co

un

t [co

un

t/1

00

ke

v]

Thick Pd

141Pr natW

A=192

W→Pt ??

~1/5000

100 ppm Pt

133Cs




report

(2) Pt region: peak structure Pt impurity in Pd in surface layer? W → Pt ? 19

RBS spectrum Pd multi-Layer without Cs dope & D2 permeation

Samle name: M115

0

200

400

600

Co

un

t [co

un

t/1

00

ke

v]

46 48 50 52 54 56 58 60

Energy [MeV]

Pd-CaOMultilayer

contamination from filament of ion source

20

0

20

40

60

Co

un

t [co

un

t/1

00

ke

v]

46 48 50 52 54 56 58 60

Energy [MeV]

Samle name: S55B

RBS spectrum Cs Doped multilayer without D2 permeation

Pd-CaO Multilayer Cs

Pt(impurity of Pd)

W

21

40

60

80

Co

un

t [co

un

t/1

00

ke

v]

46 48 50 52 54 56 58 60

Energy [MeV]

0

20

Pd-CaO Multilayer Cs

D2 Permeation

RBS spectrum

Cs Doped multilayer after D2 permeation

Samle name: SK130

Mass 〜192

W

Pt

22

200

300

400

Co

un

t [co

un

t/1

00

ke

v]

46 48 50 52 54 56 58 60

Energy [MeV]

0

100

Pd-CaOMultilayer Cs

D2 Permeation

RBS spectrum

Cs Doped multilayer after D2 permeation

Samle name: SK132

Mass 〜192

W

23

What is a peak A=192 Os? Ir?, Pt?

Samle name: SK130

40

Co

un

t [

co

unt/

100ke

v]

46 48 50 52 54 56 58 60 Energy [MeV]

0

20 ?

W

50 51 52 53 54 55 56 57 58 59

40

0

20

10

30

Co

un

t [

co

unt/1

00

ke

v]

Pt (Natural)

Ir(Natural)

Os(Natural)

20

0

10

50 52 54 56 58

Ir(Natural)

W(Natural)+4d:Transmutation

Count [

count/

100kev]

Energy [MeV] Energy [MeV]

Sample W（ng/cm2) A~192 (ng/cm2)

SK130 346±14 91.7±7.4

Sk132 697±13 90.8±5.0

Sk137 911±20 104±7

Ir natural :191Ir (37%) 193Ir(63%) 24

Conclusion

1.We performed Rutherford Backscattering Spectroscopy

(RBS) to identify 141Pr for direct nuclear mass assignment.

2. For FG samples, we could identify the 141Pr events as well

as 133Cs, although the statistics is not enough. A comparison of

the results between ICP-Ms and RBS shows that a quantitative

agreement is not good.

Y(RBS)/Y(ICP) = 0.15 ~ 1.63 for 133Cs

< 0.15 for 141Pr

→ Measurement points of ICP-MS and RBS are

different？

→ may be due to the local distribution of 141Pr

3. A broad peak indicating the existence of a nuclide with mass

number around 192 was observed. There is a possibility that

the impurity W in Pd/CaO multi-layer complex was transmuted

into the elements of mass around 192. 25

Acknowledge

RBS measurement was partially supported by IMPACT

Program of Council for Science, Technology and Innovation in

2015. Program name is “Reduction and Resource Recycle of

High Level Radioactive Wastes with Nuclear Transmutation”.

The authors would like to thank

Mr. Ryo Tajima, Dr.Yuki Honda, and Prof. Hidetoshi Kikunaga

for their corporations on RBS analysis, Research Center for

Electron Photon Science, Tohoku University and

Mr. Hideki Yoshino and Mr. Masanao Hattori for their supports.

26

W+4d 183W(19%) + 4d → 191Pt (τ1/2 = 2.8 d)

28

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