Experiments on the Synthesis of Element 113 in the Reaction 209Bi(70Zn, n)278113

Morita Kosuke, Morimoto Kouji, Kaji Daiya*, Yoshida Atsushi,

Suda Toshimi, Yoneda Akira, Haba Hiromitsu*, Ohnishi Tetsuya,

Kanungo Rituparna, Katori Kenji, Akiyama Takahiro, Ideguchi Eiji,

Yamaguchi Takayuki, Goto Sin-ichi*, Kudo Hisaaki*, Ozawa Akira,

Sueki Keisuke*, Koura Hiroyuki**, Zhao YuLiang*, and Xu HuShan

Journal of Physical Society of Japan (JPSJ)Vol. 73, 2593 - 2596

http://www.ipap.jp/jpsj/

208Pb + 58Fe → 265Hs + n208Pb + 64Ni → 271Ds + n209Bi + 64Ni → 272111 + n

208Pb + 70Zn → 277112 + n209Bi + 70Zn →

116

115

114

113

112

111

Ds

Mt

Hs

Bh

Sg

Db

Rf

Lr

No

Md

Es

Cf

Fm

One End of Nuclear Chart

162

152

SF+ or EC

-

170

176

Reaction studied at GARIS

48 Ca ind

uced

reac

tion

116

115

114

113

112

111

Ds

Mt

Hs

Bh

Sg

Db

Rf

Lr

No

Md

Es

Cf

Fm

162

152

SF+ or EC

-

170

176

Reactions studied at GARIS

265Hs 10 chains

277112 2 chains

271Ds 14 chains

272111 14 chains

116

115

114

113

112

111

Ds

Mt

Hs

Bh

Sg

Db

Rf

Lr

No

Md

Es

Cf

Fm

162

152

SF+ or EC

-

170

176

Reactions studied by GARIS

265Hs 10 chains

277112 2 chains

271Ds 14 chains

272111 14 chains

278113

New !

Summary 265Hs 10 chains271110 (Ds) 14 chains 272111 14 chains277112 2 chains

278113 1 chain 　 New!

100 102 104 106 108 110 112 114

Atomic Number

1b

1nb

10nb

100nb

100pb

10pb

1pb

0.1pb

208Pb,209Bi(HI,1n) reaction

RIKEN

Yield – Cross section

Y = ×T × B ×

typical value

Y event rate /s

cross section cm2 10-36 1 p-barn

T target thickness /cm2 1.3×1018 450 g/cm2

B beam intensity /s 3×1012 0.5 particle A

efficiency 0.5

Y= 2×10-6 /s → 1 event/6days

RILAC Facility

18GHz ECR Ion Source

RFQ-Linac

CSM　 Acc. Tanks RILAC Acc. Tanks

GARIS

Beam Energy Monitor

Required feature for a recoil separator for heavy element research

particles should be removed

1. beams of various charge states2. target recoils3. transfer products, fission fragments

come from the target

4. particles created at the position where the beam and/or other particles are stopped

causes of decreasing the efficiency

1. charge state distribution of the ion of our interest2. momentum spread of the ion3. angular spread of the ion

1. by reaction kinematics2. by multiple scattering of ion with target atoms

Principle of Operation for Gas Filled Recoil Separator-I

Magnetic Field

Reaction Products With

v & q

Vacuum

qc -1 q

c qc +1

B = mv/qe

= 0.0227A(v/v0)/q [Tm]

A: mass numberv: velocity of ionv0: Bohr velocity c/137

c

Principle of Operation for Gas Filled Recoil Separator-II

Magnetic Field with

Reaction Products With

v & q

gas

qeq

eq

q c q c

+1 q c+2 q c

+1 q c q c

-1 q c q c

-1 q c q c

+1 q c+2

Principle of Operation for Gas Filled Recoil Separator-III

Magnetic Field with

Reaction Products With

v & q

gas

qeq

eq

B = 0.0227A(v/v0)/q [Tm]

qeq = (v/v0)Z1/3 (Bohr’s theorem)

B = 0.0227A(v/v0)/qeq

B = 0.0227AZ-1/3 [Tm]

Gas-filled Recoil Separator GARIS

detectortarget

B B = m×v/q

|/| = |m/m|+|v/v|+|q/q|

in gas <<

qav: well defined → qav/q << 1

B= m×v/qav

B ： magnetic flux densitym ： mass of ionq ： charge of ionv ： velosity of ion ： radius of the ion trajectory ： mean free path of ionv0: Bhor velosity (c/137)

beam where 1 < v/v0 < Z2/3

qav = (v/v0)×Z1/3 　　 Bhor’s Theorem

B = v0×m/Z1/3

beamDifferential pumping section

D1

Bending angle 45 degreePole gap 150 mm

Radius of central ray 1200 mm

Maximum field 1.54 T

Q1, Q2

Pole length 500 mm

Bore radius 150 mm

Maximum field gradient 5.2 T/m

D2

Bending angle 10 degree

Pole gap 160 mm

Pole length 400 mm

Maximum Field 1.04 T

Magnification X -0.76Y -1.99

Dispersion 0.97 cm/%Total length 5760 mmAcceptance ±68 mrad

±57 mrad 12.2 msr

Rotating Targetr 150 mm 2000 rpm

RIKEN Gas-filled Recoil Separator GARIS

D1 Q1 Q2 D2

x y l

x -0.76 0.0 0.0 0.0 0.0 0.97

-0.48 -1.32 0.0 0.0 0.0 -6.54

y 0.0 0.0 -1.99 0.0 0.0 0.0

0.0 0.0 -6.96 -0.50 0.0 0.0

l -0.97 -0.13 0.0 0.0 1.0 -4.27

0.0 0.0 0.0 0.0 0.0 1.0

(x/x) magnification (x)

(y/y) magnification (y)

(x/) = 0

x focus

(y/) = 0

y focus

(x/) dispersion

x, y and l: [cm] and : [rad.]: [cm/%]

1st order Transfer Matrix of GARIS from Target to Focus

MCP1MCP2

SSD box

PSD

ions

Focal Plane Detectors

New Rotating Target = 300 mm, = 2000 rpmcf. old one = 125 mm, = 1000 rpm

Tested with 1pA 86Kr beam

Measurement of qeq in a helium gas0 degree target recoils

Target T [ g/cm2] Projectile Ep [MeV] ER [MeV] v/v0 Pressure [Pa]169Tm 60 40Ar 191 116±0.5 5.25±0.01 73208Pb 140 40Ar 114 56±2.3 3.29±0.07 76208Pb 120 48Ca 191 100±1.2 4.40±0.03 73208Pb 250 58Fe 282 186±2.5 6.00±0.04 76208Pb 270 64Ni 313 217±2.6 6.48±0.04 76209Bi 300 40Ar 114 22±2.3 2.06±0.11 76209Bi 130 48Ca 191 100±0.7 4.39±0.01 76209Bi 240 58Fe 282 184±2.7 5.59±0.04 76209Bi 240 64Ni 313 217±2.3 6.46±0.03 76

Recoil atoms produced by nuclear reactions

Reaction [ barn] T [ g/cm2] Ep [MeV] ER [MeV] v/v0 Pressure [Pa]Nat.Ce(58Fe, xn)193Bi 30 310 79±0.3 4.06±0.01 76Nat.Ce(64Ni, xn)196Po 30 310 91±0.3 4.33±0.01 76Nat.Ce(58Fe, pxn)200At 30 310 93±0.3 4.33±0.01 76169Tm(40Ar, 5n)204Fr 210 191 34±0.6 2.59±0.02 76169Tm(40Ar, 6n)203Fr 210 197 35±0.6 2.63±0.02 76

169Tm(48Ca, 5n)212Ac 210 218 45±0.9 2.92±0.03 76197Au(40Ar, 3n)234Bk 260 197 31±0.9 2.31±0.03 76208Pb(40Ar, 3n)245Fm 18 n 210 197 30±0.7 2.22±0.03 76208Pb(48Ca, 2n)254No 3 250 218 39±1.0 2.47±0.03 76209Bi(48Ca, 2n)255Lr 0.4 250 218 38±0.8 2.46±0.02 76

PbBi

PoAtRn

FrRa

AcTh

PaU

NpPu

AmCm

Bk

CfEs

Fm

MdNo

LrRfDb

SgBh

HsMt

110111

112

113

0

10

20

30

40

50

60

12.5 13.0 13.5 14.0 14.5 15.0 15.5

B (kGauss)

Tra

nsm

issi

on (

%)

FWHM = 5.3% 245Fm

detector size

20

18

16

14

12

10

8

6

4

5 10 15 20 25 30

(v/v0)Z1/3

qeq

Boh

r’s th

eore

m

208Pb

209Bi

169Tm

208Pb

209Bi

198At

192Bi

265Hs

209Bi

208Pb

212Ac

234Bk

245Fm

255Lr254No

204Fr

203Fr

271110272111

v0: Bohr velocity

0.0

0.2

0.4

0.6

0.8

1.0

1.5 2.0 2.5 3.0 3.5v/v0

Tra

nsm

issi

on

Positional Distribution at Focal Plane

0

100

200

300

400

500

600

700

-100 -50 0 50 100

Position (mm)

Bi(.0.11AMeV)Pb(0.26AMeV)simulationsimulation

P(He) = 67 Pa (0.5Torr)L = 500 cm

0 20 40 60 80 1000

10

20

30

40

50

Performance of detection system

Energy / MeV

Co

un

ts p

er 1

0 k

eV

TOF / ns

En

erg

y /

MeV

209209Bi+Bi+6464Ni reaction (Main.033, strip 13)Ni reaction (Main.033, strip 13)

272272111111

0 5 10 15 20 251

10

100

0

5

0

5

8 9 10 11 12

8 9 10 11 12

TotalTotal

Total [ ROI = 8 - 12MeV ]Total [ ROI = 8 - 12MeV ]

Anti-coincidence with TOF detectorsAnti-coincidence with TOF detectors

ER-ER- correlation ( correlation (PP=+/-1 mm, =+/-1 mm, =30 s)=30 s)

272272111111268268MtMt264264BhBh260260DbDb256256LrLr

TOF-energy spectrumTOF-energy spectrum ER-ER- correlation analysis correlation analysis

Beam-like particles

Target-like particles

Light charged particles

8 9 10 11 120

5

0.5 cps0.5 cps

2.4x102.4x10-2-2 cps cps

1.8x101.8x10-3-3 cps cps

Beam 64Ni 0.4 ～ 1 pA

310 MeV 1.0 x 1018 14 days 1 event 313 MeV 1.0 x 1018 12 days 4 event 316 MeV 1.1 x 1018 7 days 9 event 320 MeV 1.0 x 1018 7 days 0 event Total 4.1 x 1018 40 days 14 event

Target 208Pb 190 ～ 250 g/cm2 (98% enriched) evaporated on 30 g/cm2 Ccovered by 10 g/cm2 C

B (GARIS) 2.05 TmP (GARIS) 75 Paε(GARIS) 　　 0.8Total Counting rate 10 ～ 20 cps

208Pb(64Ni, n)271Ds 　 Experimental condition

E(lab.)MeV ion dose day events

310 1.0 x 1018 14 1

313 1.0 x 1018 12 4

316 1.1 x 1018 7 9

320 1.0 x 1018 7 0

total 4.1 x 1018 40 14

CN271Ds

267Hs

255No

259Rf

263Sg

251Fm

25-Sep-2002

239 ms10.71 MeV (PSD+SSD)

66.0 ms10.09 MeV (PSD+SSD)

48.0 ms10.83 MeV (PSD+SSD)

2.71s10.46 MeV (PSD+SSD)

58.4 s7.73 MeV (PSD)

Eproj=313MeV

26-Jul-2002

CN271Ds

267Hs

255No

259Rf

263Sg

2.2 ms10.73 MeV (PSD)

68.0 ms9.82 MeV (PSD)

18.0 ms8.71 MeV (PSD+SSD)

3.13 s8.87MeV (PSD)

208Pb(64Ni,n)271Ds

251Fm

394.7 s s

8.07 MeV (PSD)

Eproj=313MeV

11

1110

10

10

9

9

9

9

98

8

8

7

1

2

3

4

5

11

11

1110

8

8

E (MeV)

5

0

5

0

5

0

5

0

5

0

Cou

nts/

100k

eV

1

2

3

4

5

Tdecay (sec)

Cou

nts/

bin 0

1000s10s0.1s1ms

5

05 1000s10s0.1s1ms

1000s10s0.1s1ms

1000s10s0.1s1ms

1000s10s0.1s1ms

5

0

5

0

5

0

10s

=2.9ms =120ms

=77ms

=1.0s

=3.7s

=220s

251Fm 255No 259Rf 263Sg 267Hs 271Ds12345

0

5

10

15

20

25

30

35

40

300 305 310 315 320 325

(pb)

E(64Ni) /MeV (lab.)

RIKEN

GSI

208Pb + 64Ni → 271Ds + n

statistical (1)

errors

energy loss in the target

Excitation function of 208Pb(64Ni,n)271Ds

Nuclei n T1/2

271Ds 11 1.63+0.44

-0.29ms improved

271mDs 3 69+56

-21ms confirmed

267Hs 12 52+13

- 8ms improved

267mHs 1 0.80+3.8

-0.38s possible

Eopt(lab.) = 314 MeV

Eopt(cm) = 240 MeV

208Pb + 64Ni → 271Ds + n 　

Beam 64Ni 0.7 ～ 1.8 pA

320 MeV 2.0 x 1018 8 days

323 MeV 8.2 x 1018 34 days 326 MeV 2.5 x 1018 8 days

Total 1.27 x 1019 ions 50 days

Target 209Bi 210 ～ 310 g/cm2 evaporated on 30 g/cm2 Ccovered by 10 g/cm2 C

B (GARIS) 2.05 Tm

P (GARIS) 75 Paε(GARIS) 0.8Total Counting rate 2 ～ 10 cps

Experimental condition 209Bi(64Ni,n)272111

E(lab.)MeV ion dose day events

320 2.0 x 1018 8 3

323 8.2 x 1018 34 11

326 2.5 x 1018 8 0

total 1.27 x 1019 50 14

CN272111

268Mt

260Db

264Bh

26-Feb-2003

7.11 ms10.82 MeV (PSD+SSD)

0.715 ms10.28 MeV (PSD)

0.54 s9.57 MeV (PSD)

1.71 s231 MeV (PSD+SSD)

Eproj=323MeV

CN272111

268Mt

256Lr

260Db

264Bh

26-Feb-2003

1.42 ms11.25 MeV (PSD)

36.6 ms10.43 MeV (PSD+SSD)

1.87 s9.66 MeV (PSD+SSD)

1.52 s9.40 MeV (PSD)

2.82 ms11.31 MeV (LG)

CN272111

268Mt

256Lr

260Db

264Bh

8-Apr-2003

44 ms10.78 MeV (PSD+SSD)

0.44 s9.58 MeV (PSD)

48.46 s8.81 MeV (PSD)

209Bi(64Ni,n)272111

S.F.

6th

5th

4th

CN272111

268Mt

264Bh

15-Apr-2003

8.89 ms10.96 MeV (PSD+SSD)

26.18 ms2.76 MeV (PSD)esc

0.97 s208 MeV (PSD)

Eproj=323MeV

CN272111

268Mt

256Lr

260Db

264Bh

252Md

14-Apr-2003

1.17 ms10.58 MeV (LG)

38.33 ms10.35 MeV (PSD)

3.6 ms9.31 MeV (PSD)

4.87 s9.01 MeV (PSD)

45.84 s8.50 MeV (PSD)

5.11 ms11.06 MeV (PSD)

CN272111

268Mt

256Lr

260Db

264Bh

252Md

16-Apr-2003

19.1 ms10.43 MeV (PSD)

1.34 s9.50 MeV (PSD)

3.69 s9.10 MeV (PSD)

7.87 s8.41 MeV (PSD)

209Bi(64Ni,n)272111

S.F.

9th

8th

7th

0

5

0

5

0

5

0

5

0

5

Cou

nts

/ bi

n 0

5

0

5

0

5

Cou

nts

/ 10

0 ke

V

E α / MeV

0

5

8 9 10 11 120

5

1

2

3

4

5

1

2

3

4

5

10000s100s1s10ms100s

Tdecay

252Md ← 256Lr ← 260Db ← 264Bh ← 268Mt ← 272111

=5.5ms

=30ms

=1.3s

=2.2s

=27s

　 α ３α ５ 　 α ４ 　 α ２ α １

(sec)

α １ α １

α ２ α ２

α ３ α ３

α ４ α ４

α ５α ５

=27s

272111 excitation fnction

- 1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

305.0 310.0 315.0 320.0 325.0 330.0Elab (MeV)

(pb)

GSIRIKEN

Excitation function of 209Bi(64Ni,n)272111

Nuclei n T1/2

E Efiss.

MeV

272111 14 3.8+1.4

- 0.8ms 10.2~11.56

268Mt 14 21+8

- 5ms 9.4~10.77

264Bh 14 0.89+0.31

- 0.19s 8.86~9.83

208

206

260Db 12 5.7+2.3

- 1.3s 8.35~9.4 231

256Lr 8 18+10

- 5s 8.35~8.65

Eopt(lab.) = 319 MeV

Eopt(cm) = 244 MeV

Summary of 209Bi + 64Ni → 272111 + n

period 9/5/2003 ～ 12/29/2003Beam Energy 5.03 AMeV

348 MeV at target half depth

Total Dose 1.21x1019

Target Thickness 1.37x1018 /cm2 (0.48 mg/cm2)_GARIS 0.8 (assumption)(1-ev.) 7.5x10-38 cm2

upper limit (1) 1.38x10-37 cm2

Irradiation time 1390 Hours (58 Days / 74 Days)Beam Intensity 2.42x1012 /s (0.4 p-A)

Summary of 209Bi + 70Zn experiment

100 102 104 106 108 110 112 114

Atomic Number

1b

1nb

10nb

100nb

100pb

10pb

1pb

0.1pb

208Pb,209Bi(HI,1n) reaction

present work

period 2004/4/2 ～ 2004/5/24Beam Energy 346 MeV at target half depth

Total Dose 4.4x1018

Target Thickness 450 μg/cm2

number of events 2 0.44+0.59

-0.29 pb

Irradiation time 693 Hours (28.9 Days)Beam Intensity 1.76x1012 /s (0.3 p-A)Total counting rate ～ 1 cps

Experimental condition 208Pb(70Zn, n)277112

277112

273Ds

269Hs

265Sg

261Rf

CN

11.09 ± 0.07 MeV1.10 ms23.57 mm

11.14 ± 0.04 MeV0.52 ms23.45 mm

9.17 ± 0.04 MeV14.19 s23.34 mm

8.71 ± 0.04 MeV23.02 s23.45 mm

197.3 MeV2.97 s23.41 mm

34.42 MeV23.33 mm

16-April-2004E (70Zn) = 349.5 MeV

Observed events at RIKENin 208Pb + 70Zn reaction

277112

273Ds

269Hs

265Sg

261Rf

CN

11.32 ± 0.04 MeV1.22 ms18.31 mm

11.15±0.07MeV (2nd trig. PSD+SSD)39.9 s20.18 mm

9.25 ± 0.07 MeV(PSD+SSD)0.270 s19.03 mm

8.70 ± 0.04 MeV79.9 s18.05 mm

156.3 MeV8.3 s18.50 mm

35.13 MeV18.45 mm

22-May-2004E (70Zn) = 349.5 MeV

Strip #8 Strip #11

277112

273Ds

269Hs

265Sg

261Rf

257No

253Fm

CN

11.45 MeV280 s17.85 mm

11.08 MeV110 s17.77 mm

9.23 MeV19.7 s17.81 mm

4.60 MeV7.4 s17.57 mm

8.52 MeV4.7 s17.96 mm

8.34 MeV15.0 s17.91 mm

32.04 MeV18.06 mm

277112

273Ds

269Hs

265Sg

261Rf

CN

11.17 MeV1406 s26.03 mm

11.20 MeV310 s26.01 mm

9.18 MeV22.0 s26.16 mm

0.2 MeV18.8 s27.33 mm

153 MeV14.5 s26.70 mm

24.09 MeV26.06 mm

09-Feb-1996E(70Zn) = 343.8 MeV

05-May-2000E (70Zn) = 346.1 MeV

Observed events at GSIin 208Pb + 70Zn reaction

ref.1 Hofmann S. et al., Z. Phys. A354, 229 (1996) 208Pb + 70Zn → 277112 + n2 Hofmann S. and Münzenberg G., Rev. Mod. Phys. 72, 733

(2000)

208Pb + 70Zn → 277112 + n

3 present 208Pb + 70Zn → 277112 + n4 present 208Pb + 70Zn → 277112 + n5 Lazarev Yu. A. et al., Phys. Rev. C54, 620 (1996) 244Pu + 34S → 273Ds + 5n6 Lazarev Yu. A. et al., Phys. Rev. C62, 064307(2000) 244Pu + 22Ne → 261Rf + 5n

GSI RIKEN FLNRref. 1 2 3 4 5 6

277112 11.45 11.17 11.09±.07 11.32±.040.28 ms 1.41 ms 1.10 ms 1.22 ms

273Ds 11.08 11.20 11.14±.04 11.15±.07 11.350.11 ms 0.31 ms 0.52 ms 0.04 ms 0.39 ms

269Hs 9.23 9.18 9.17±.04 9.25±.0719.7 s 22.0 s 14.2 s 0.27 s

265Sg 4.60 0.20 8.71±.04 8.70±.04 8.6374.0 s 18.8 s 23.0 s 79.9 s 158 s

261Rf 8.52 153 197 156 8.30±0.064.70 s 14.5 s 2.97 s 8.30 s 54+8

-4 s257No 8.34 8.22 8.24, 8.34

15.0 s 384 s 17 s

10s 1ms 0.1s 10s 1000s

277112 = 1.0 ms

273Ds = 0.24 ms

269Hs = 14 s

265Sg = 32 s

261Rf = 7.6 s

T_decay/s

RIKEN

GSI

154 156 158 160 162 164 166

RIKENGSISUM

Neutron Number

10-3

10-4

103

102

101

100

10-1

10-2

T_d

ecay

(s) 257No 261Rf 265Sg 269Hs

273Ds

277112

0.25

14

1.0

32

7.6

277112273Ds269Hs265Sg261Rf

ms+0.25-0.08

s+14-5

ms+1.0-0.3

s+32-11

s+7.6-2.5

0.69 ms+0.69-0.23

9.7 s+9.7-3.2

0.17 ms+0.17-0.06

22 s+22-8

5.3 s+5.3-1.8

T1/2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

330 335 340 345 350

Elab (MeV)

(pb

)GSIRIKEN

Masses of Beams & TargetsAudi & Wapstra, Nucl. Phys A565, 1 (1993)

Masses of Compound NucleiMyers & Swiatecki, Nucl. Phys. A601, 141 (1996)

5 10 15 20Ex of C.N. (MeV)

20

10

4

2

1

0.5

0.3

0.20.1

(p

b)272Ds

273111

278112

279113

Calculated threshold of fission after 1n emission

Sn

(A – n) + n

A

B + T

B + T + EcmSn

saddle point

DeformationBf

Second chance fissionsreshold

saddle point

Deformation

Energy diagram of 1n emission

Ecm

Ex(

CN

)

period 2003/9/5 ～ 2004/8/1Beam Energy 5.03 AMeV

348 MeV at target half depth

Total Dose 1.7x1019

Target Thickness 1.37x1018 /cm2 (0.48 mg/cm2)_GARIS 0.8 (assumption)(1-ev.) 5.5x10-38 cm2

55 +154-47 fb

Irradiation time 1920 Hours (80 Days / 97 Days)Beam Intensity 2.42x1012 /s (0.4 p-A)

Summary of 209Bi + 70Zn experiment

278113

274111

270Mt

266Bh

CN11.68 MeV (PSD)344 　 μs30.49 mm

11.15 MeV6.15+5.00 (PSD+SSD)9.26 ms30.40 mm

10.03 MeV 1.14+8.89(PSD+SSD)7.16 ms29.79 mm

9.08 MeV (PSD)2.47 s30.91 mm

36.75 MeVTOF 44.61 ns30.33 mm

23-July-2004 18:55 (JST)E (70Zn) = 349.0 MeV

209Bi + 70Zn → 278113 + n

Strip #12

262Db

204.1 MeV(PSD)40.9 s30.25 mm

= 55 fb +154-47

100 102 104 106 108 110 112 114

Atomic Number

1b

1nb

10nb

100nb

100pb

10pb

1pb

0.1pb

208Pb,209Bi(HI,1n) reaction

RIKEN

8.00

8.50

9.00

9.50

10.00

10.50

11.00

11.50

12.00

12.50

156 158 160 162 164 166

113112

N

Q

/ MeV

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

156 158 160 162 164 166

ExpTheo

3系列4系列

T1/

2113

112calc

calc

N

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

156 158 160 162 164 166

112113

Hin

dran

ce F

acto

r (T

exp/

Tca

lc)

dcZQbaZTcalc 10log

Viola & Seaborg の現象論

a=1.81040, b=-21.7199, c=-0.26488, d=-28.1319by Smolanczuk, Phys. Rev. C56(1997)812

N

1.E- 04

1.E- 03

1.E- 02

1.E- 01

1.E+00

1.E+01

1.E+02

1.E+03

152 154 156 158 160 162 164 166

1系列2系列

110108106

104

111

Summary• 278113 was produced by 209Bi(70Zn,n) reaction.

• 278113()→274Rg()→270Mt()→266Bh()→262Db(SF)

• Identification was based on– connected to the known decays 266Bh()→262Db(SF)– reaction energy systematics– cross section systematics

• Z & A of 278113 are largest ones among the isotopes whose Z & A were determined experimentally.

• N=162 shell effect– second example that -decay chain cross the N=162 (cf. 277112).

278

294

116 289 290 292

115 287 288

114 287 288 289

113 283 284

112 277 283 284 285

272 279 280

269 270 271 273 280 281

268 275 276

267 277

266 267 271 272

265 266

267 268

170

176

111

Ds

Mt

Hs

Bh

Sg

Db

117

118

269

283 286

238U + 40Ar

232Th + 40Ar

Cold Fusion Reaction

70Zn64Ni

68Zn

76Ge

82Se86Kr

N=162

Future plan

238U + 58Fe