Transcript Synthesis of the heaviest elements at RIKEN

Synthesis of the heaviest elements at RIKEN
Kosuke Morita
Superheavy Element Laboratory
RIKEN Nishina Center
Dr. Yoshio Nishina with his Cyclotron
2009/1/20
Periodic Table of D.I. Mendeleev.
The new superheavy elements
1
The first attempt to
synthesize an artificial new
element at RIKEN, Japan
238U(n,2n)237U(6.5day
b-)
238U(n,g)239U(23.5m
b-)
b-)
E. McMillan and
P. H. Abelson
Phys. Rev. 57(1940)1185
239Np(2.3day
Y. Nishina, T. Yasaki,
H. Ezoe, K. Kimura,
And M. Ikawa,
Phys. Rev. 57(1940)1182
232Th(n,2n)231Th(25day
b-)
Y. Nishina, T. Yasaki,
H. Ezoe, K. Kimura,
And M. Ikawa,
Nature, 142(1940)874
2009/1/20
Periodic Table of D.I. Mendeleev.
The new superheavy elements
2
RARF: Riken Accelerator Research
Facility est. since 1986
RIKEN GARIS 1987 - 1999
GARIS/IGiSOL
RIPS
2009/1/20
Periodic Table of D.I. Mendeleev.
The new superheavy elements
3
RIKEN GARIS 2001 - 2009
2009/1/20
Periodic Table of D.I. Mendeleev.
The new superheavy elements
4
RILAC Facility
CSM Acc. Tanks
RILAC Acc. Tanks
RFQ-Linac
Beam Energy Monitor
GARIS
2009/1/20
18GHz ECR Ion Source
RIKEN GARIS 2001 - 2009
Periodic Table of D.I. Mendeleev.
The new superheavy elements
5
New Recoil Separator GARIS-II
RIKEN GARIS 2009     67
    58
  12
mrad
msr
GARIS
    55
mrad
    120
mrad
  23
msr
GARIS－II
M
BP
M BP
GARIS-II
mrad
GARIS
2009/1/20
Periodic Table of D.I. Mendeleev.
The new superheavy elements
6
GARIS-II
X [cm]
Y[cm]
20
15
10
5
0
-5
-10
-15
-20 0
ion optics
2
3
4
Z [m]
5
mrad
    120
mrad
  23
msr
6
2008/9/17
87
87
36
30
6
252
172
91
65
44
1
    55
International School of Nuclear
Physics at Erice
7
RIKEN Gas-filled Recoil Separator GARIS
D1
Bending angle
Pole gap
Radius of central ray
Maximum field
Q1, Q2
Pole length
Bore radius
Maximum field gradient
D2
Bending angle
Pole gap
Pole length
Maximum Field
Differential pumping section
Rotating Target
r 150 mm
w 2000 rpm
D1
Q1
Q2
500 mm
150 mm
5.2 T/m
10 degree
160 mm
400 mm
1.04 T
D2
Magnification
Dispersion
Total length
Acceptance
2008/9/17
45 degree
150 mm
1200 mm
1.54 T
International School of Nuclear
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X
Y



-0.76
-1.99
0.97 cm/%
5760 mm
±68 mrad
±57 mrad
12.2 msr
8
Focal Plane Detectors
MCP2
ions
PSD
SSD box
MCP1
2008/9/17
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9
Reactions studied at RIKEN-GARIS
277112
272Rg
278113
14 chains
115
114
271Ds
14 chains
263, 264, 265Hs
2 chains
116
176
113
112
208Pb(58Fe,
111
208Pb(64Ni,
Ds
Mt
170
Hs
209Bi(64Ni,
Sg
209Bi(70Zn,
Db
Rf
Lr
No
Md
Fm
Es
Cf
265Sg
162
152
2008/9/17
n)271Ds
n)272Rg
208Pb(70Zn,
Bh
a 261Rf
SF
b+ or EC
b-
New !
International School of Nuclear
Physics at Erice
n)265Hs
n)277112
n)278113
207Pb(58Fe,
n)264Hs
206Pb(58Fe,
n)263Hs
208Pb(56Fe,
n)263Hs
208Pb(58Fe,
2n)264Hs
248Cm(18O,5n)261Rf
248Cm(22Ne,5n)265Sg
10
248Cm(23Na,5n)266Bh
Yield – Cross section (sensitivity)
Y = s×T × B × e
typical value
Y
event rate
/s
s
cross section
cm2
10-36
T
target thickness
/cm2
1.3×1018
B
beam intensity
/s
4×1012
e
efficiency
1 p-barn
450 mg/cm2
0.65 particle mA
0.8
Y= 4×10-6 /s → 1 event/3days
2008/9/17
International School of Nuclear
Physics at Erice
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2008/9/17
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a
Eproj=313MeV
26-Jul-2002
a
a
255No
259Rf
25-Sep-2002
a
18.0 ms
8.71 MeV (PSD+SSD)
a
3.13 s
8.87MeV (PSD)
263Sg
a
394.7 s s
251Fm
Eproj=313MeV
68.0 ms
9.82 MeV (PSD)
263Sg
a
208Pb(64Ni,n)271Ds
CN
2.2 ms
10.73 MeV (PSD)
267Hs
a
271Ds
8.07 MeV (PSD)
a
a
251Fm
255No
259Rf
267Hs
271Ds
CN
239 ms
10.71 MeV (PSD+SSD)
66.0 ms
10.09 MeV (PSD+SSD)
48.0 ms
10.83 MeV (PSD+SSD)
2.71s
10.46 MeV (PSD+SSD)
58.4 s
7.73 MeV (PSD)
251Fm
 255No  259Rf  263Sg  267Hs  271Ds
a5
a4
a3
a2
a1
t=2.9ms
5
t=120ms
a1
a1
0
1ms
0.1s
10s
t=77ms
1000s
a2
8
Counts/100keV
Counts/bin
0
5
5
5
11
9
a2
0
0
5
1ms
0.1s
10s
t=1.0s
0
5
1ms
a4
0.1s
1000s
a3
10s
1000s
8
9
10
5
a3
0
8
9
10
5
t=3.7s
1ms
0.1s
10ms
1ms
1000s
8
9
10
5
t=220s
a5
0
10s
10s
1000s
Tdecay (sec)
11
a5
0
0.1s
11
a4
0
0
5
11
7
8
9
10
Ea (MeV)
11
208Pb
Nuclei
n
271Ds
11
271mDs
267Hs
267mHs
3
12
1
+ 64Ni → 271Ds + n
T1/2
+0.44
-0.29
ms
improved
69
+56
-21
ms
confirmed
52
+13
-8
ms
improved
+3.8
-0.38
s
possible
1.63
0.80
Eopt(lab.) = 314
Eopt(cm) = 240
MeV
MeV
a
Eproj=323
MeV
a
a
4th
a
256Lr
268Mt
260Db
264Bh
272111
CN
26-Feb-2003
1.42 ms
11.25 MeV (PSD)
36.6 ms
10.43 MeV (PSD+SSD)
a
1.87 s
9.66 MeV (PSD+SSD)
a
1.52 s
9.40 MeV (PSD)
260Db
a
264Bh
268Mt
272111
a
a
256Lr
26-Feb-2003
0.715 ms
10.28 MeV (PSD)
S.F.
5th
CN
7.11 ms
10.82 MeV (PSD+SSD)
0.54 s
9.57 MeV (PSD)
1.71 s
231 MeV (PSD+SSD)
209Bi(64Ni,n)272111
260Db
264Bh
a
268Mt
a
272111
CN
2.82 ms
11.31 MeV (LG)
44 ms
10.78 MeV (PSD+SSD)
0.44 s
9.58 MeV (PSD)
48.46 s
8.81 MeV (PSD)
6th
8-Apr-2003
a
Eproj=323MeV
a
a
252Md
256Lr
a
264Bh
a
7th
260Db
268Mt
272111
14-Apr-2003
1.17 ms
10.58 MeV (LG)
38.33 ms
10.35 MeV (PSD)
3.6 ms
9.31 MeV (PSD)
4.87 s
9.01 MeV (PSD)
45.84 s
8.50 MeV (PSD)
CN
a
a
268Mt
209Bi(64Ni,n)272111
272111
CN
8.89 ms
10.96 MeV (PSD+SSD)
26.18 ms
2.76 MeV (PSD)esca
264Bh
S.F.
264Bh
a
a
a
252Md
256Lr
268Mt
a
0.97 s
208 MeV (PSD)
8th
15-Apr-2003
260Db
272111
CN
5.11 ms
11.06 MeV (PSD)
19.1 ms
10.43 MeV (PSD)
1.34 s
9.50 MeV (PSD)
3.69 s
9.10 MeV (PSD)
7.87 s
8.41 MeV (PSD)
9th
16-Apr-2003
← 256Lr ← 260Db ← 264Bh ← 268Mt ← 272111
α３
α４
α２
α１
α５
5
a1
5
t=5.5ms
α１
0
Counts / bin
5
a2
t=30ms
α２
0
5
a3 α３
t=1.3s
0
5
Counts / 100 keV
252Md
α１ a1
0
5
0
5
t=27s
a4
α４
0
0
5
5
a5
α５
t=27s
0
0
100ms
10ms
1s
100s
Tdecay (sec)
10000s
α３a3
0
5
t=2.2s
α２ a2
α４a4
a5
α５
8
9
10
11
Eα / MeV
12
Summary of
Nuclei
n
209Bi
+ 64Ni → 272111 + n
Ea
T1/2
272111
14
3.8
268Mt
14
21
264Bh
14
0.89
260Db
12
5.7
256Lr
8
18
+1.4
- 0.8
+8
-5
+0.31
- 0.19
+2.3
- 1.3
+10
-5
Eopt(lab.)
= 319
MeV
Eopt(cm)
= 244
MeV
Efiss.
MeV
ms
10.2~11.56
ms
9.4~10.77
s
8.86~9.83
208
206
s
8.35~9.4
231
s
8.35~8.65
Experimental condition 208Pb(70Zn, n)277112
period
Beam Energy
2004/4/2 ～ 2004/5/24
346 MeV at target half depth
Total Dose
4.4x1018
Target Thickness 450 μg/cm2
number of events 2
s
0.44+0.59-0.29 pb
Irradiation time
Beam Intensity
Counting rate
693 Hours (28.9 Days)
1.76x1012 /s (0.3 p-mA)
～1 cps
J. Phys. Soc. Jpn., Vol. 76, No. 4, p.043201(2007)
2008/9/17
International School of Nuclear
Physics at Erice
20
Observed events at RIKEN
in 208Pb + 70Zn reaction
16-April-2004
E (70Zn) = 349.5 MeV
265Sg
261Rf
8.71 ± 0.04 MeV
23.02 s
23.45 mm
197.3 MeV
2.97 s 2008/9/17
23.41 mm
261Rf
265Sg
35.13 MeV
18.45 mm
CN
11.09 ± 0.07 MeV
1.10 ms
23.57 mm
11.14 ± 0.04 MeV
0.52 ms
23.45 mm
9.17 ± 0.04 MeV
14.19 s
23.34 mm
Strip #11
34.42 MeV
23.33 mm
277112
273Ds
269Hs
Strip #8
269Hs
277112
273Ds
CN
11.32 ± 0.04 MeV
1.22 ms
18.31 mm
11.15±0.07MeV (2nd trig. PSD+SSD)
39.9 ms
20.18 mm
9.25 ± 0.07 MeV(PSD+SSD)
0.270 s
19.03 mm
8.70 ± 0.04 MeV
79.9 s
18.05 mm
156.3 MeV
8.3 s International School of Nuclear
Physics at Erice
18.50 mm
22-May-2004
E (70Zn) = 349.5 MeV
21
277112
Observed events at GSI
in 208Pb + 70Zn reaction
CN
32.04 MeV
18.06 mm
11.45 MeV
280 ms
17.85 mm
273Ds
277112
09-Feb-1996
E(70Zn) = 343.8 MeV
11.08 MeV
110 ms
17.77 mm
269Hs
273Ds
9.23 MeV
19.7 s
17.81 mm
265Sg
4.60 MeV
7.4 s
17.57 mm
265Sg
257No
8.52 MeV
4.7 s
17.96 mm
261Rf
8.34 MeV
15.0 s
253Fm 2008/9/17
17.91 mm
153 MeV
11.17 MeV
1406 ms
26.03 mm
9.18 MeV
22.0 s
26.16 mm
0.2 MeV
18.8 s
27.33 mm
International
School of Nuclear
14.5 s
Physics at Erice
26.70 mm
CN
11.20 MeV
310 ms
26.01 mm
269Hs
261Rf
24.09 MeV
26.06 mm
05-May-2000
E (70Zn) = 346.1 MeV
22
GSI
ref.
277112
273Ds
269Hs
265Sg
261Rf
257No
1
11.45
0.28 ms
11.08
0.11 ms
9.23
19.7 s
4.60
74.0 s
8.52
4.70 s
8.34
15.0 s
2
11.17
1.41 ms
11.20
0.31 ms
9.18
22.0 s
0.20
18.8 s
153
14.5 s
RIKEN
3
11.09±.07
1.10 ms
11.14±.04
0.52 ms
9.17±.04
14.2 s
8.71±.04
23.0 s
197
2.97 s
4
5
11.32±.04
1.22 ms
11.15±.07 11.35
0.04 ms
0.39 ms
9.25±.07
0.27 s
8.63
8.70±.04
79.9 s
158 s
156
8.30 s
8.22
384 s
ref.
1
Hofmann S. et al., Z. Phys. A354, 229 (1996)
2
Hofmann S. and Münzenberg G., Rev. Mod. Phys. 72, 733
(2000)
3
present
4
present
5
Lazarev Yu. A. et al., Phys. Rev. C54, 620 (1996)
6
Lazarev Yu. A. et al., Phys. Rev. C62, 064307(2000)
2008/9/17
FLNR
International School of Nuclear
Physics at Erice
6
8.30±0.06
54+8-4 s
8.24, 8.34
17 s
+ 70Zn → 277112 + n
208Pb + 70Zn → 277112 + n
208Pb
+ 70Zn → 277112 + n
208Pb + 70Zn → 277112 + n
244Pu + 34S → 273Ds + 5n
244Pu + 22Ne → 261Rf + 5n
208Pb
23
N=165
277112
t = 1.0 ms
N=163
273Ds
t = 0.24 ms
RIKEN
N=161
269Hs
N=159
265Sg
GSI
t = 14 s
t = 32 s
N=157
261Rf
10ms
2008/9/17
t = 7.6 s
1ms
0.1s
10s
International School of Nuclear
T_decay/s
Physics at Erice
1000s
24
t
277112
1.0 +1.0
-0.3 ms
273Ds
0.25 +0.25
-0.08 ms
269Hs
14 +14
-5 s
265Sg
32 +32
-11 s
261Rf
7.6 +7.6
-2.5 s
2008/9/17
T1/2
0.69+0.69
-0.23 ms
0.17+0.17
-0.06 ms
9.7 +9.7
-3.2 s
22 +22
-8 s
5.3 +5.3
-1.8 s
International School of Nuclear
Physics at Erice
25
Summary of 209Bi + 70Zn experiment
period
Beam Energy
2003/9/5 ～ 2008/3/31
5.03 AMeV
348 MeV at target half depth
Total Dose
Target Thickness
e_GARIS
s(2-ev.)
8.5x1019
1.3x1018 /cm2
0.8
2.3x10-38 cm2
23 +30-15 fb
Irradiation time
Beam Intensity
7477 Hours (312 Days)
3.0x1012 /s (0.5 p-mA)
(0.45 mg/cm2)
J. Phys. Soc. Jpn., Vol. 73, No. 10, p.2593(2004)
2008/9/17
International School of Nuclear
Physics at Erice
26
20
272Ds
10
s (pb)
4
2
1
0.5
0.3
0.2
0.1
2008/9/17
273111
278112
279113
Calculated threshold of fission
after 1n emission
Masses of Beams & Targets
Audi & Wapstra, Nucl. Phys A565, 1 (1993)
Masses of Compound Nuclei
Myers & Swiatecki, Nucl. Phys. A601, 141 (1996)
5 10 International
15 20 School of Nuclear
Ex of C.N. (MeV)
Physics at Erice
27
2009/1/20
Periodic Table of D.I. Mendeleev.
The new superheavy elements
28
209Bi
+
70Zn
→
278113
+ n
278113
23-July-2004 18:55 (JST)
a
1st chain
1st chain
a
a
270Mt
36.75 MeV
TOF 44.61 ns
30.33 mm
274111
36.47 MeV
TOF 45.69 ns
30.08 mm
CN
278113
a
11.68 MeV (PSD)
344 μs
30.49 mm
11.15 MeV
6.149+5.003 (PSD+SSD)
270Mt
9.260 ms
30.40 mm
a
a
274111
CN
11.52 MeV (PSD)
4.93 ms
30.16 mm
0.88+10.43=11.31 MeV
(PSD+SSD)
34.3 ms
29.61 mm
10.03 MeV
2.32 MeV (escape)
1.136+8.894(PSD+SSD)
1.63 s
266Bh
266Bh
7.163 ms
29.45 mm
s = 23 fb
29.79 mm
a
a
2nd chain
9.08 MeV (PSD)
9.77 MeV (PSD)
2.469 s
1.31 s
2-April-2005 2:18 (JST)
262Db
262Db
30.91 mm
29.65 mm
204.05 MeV(PSD)
40.9 s
s.f.2008/9/17
30.25 mm
192.32 MeV(PSD)
International
of Nuclear
0.787School
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s.f. Physics
at Erice
30.47 mm
29
N=165
278113
N=163
t = 2.6 ms
274Rg
t = 21.8 ms
RIKEN
N=161
270Mt t = 0.82 s
N=159
266Bh
t = 1.89 s
N=157
262Db
10ms
2008/9/17
t = 20.8 s
1ms
0.1s
10s
International School of Nuclear
T_decay/s
Physics at Erice
1000s
30
Hindrance Factor (Texp/Tcalc)
1.E+03
1000
112
113
113-2
Bh
1.E+02
100
Mt
Rg
113
1.E+01
10
Hs
1.E+00
1
1.E-01
0.1
Rf
Ds
112
Sg
158
160
162
164
156 158
162
164
160
neutron number
156
166
166
Systematics by Viola & Seaborg
log 10 Tcalc   aZ  b 
2008/9/17
Qa  cZ  d 
a=1.81040, b=-21.7199, c=-0.26488, d=-28.1319
International
Nuclear
by Smolanczuk,
Phys.School
Rev. ofC56(1997)812
Physics at Erice
31
248Cm(18O,5n)261Rf
α spectrum of MANON
30
2 14
20
T ra n sp o rt e fficie n cy / %
Rn)
P o (B .G .:
2 22
40
7 .6 8 7
C o u n ts / 4 0 ke V
50
10
0
6
7
8
9
10
11
a -p a rticle e n e rg y / M e V
GARIS efficiency
12
Dose: 6.3×1017
Chamber: 49 kPa
He: 2 L/min
KCl: 620 oC
Coll. step: 30 s
7 up detectors
8 .2 8 0 2 6 1 R f
8 .2 2 , 8 .3 2 2 5 7 N o
60
12
10
8
6
4
2
0
1 .2
1 .4
1 .6
1 .8
2 .0
2 .2
M a g n e tic rig id ity, B  / T m
No background peaks at > 8 MeV
161 α (58 α-α) / 8.2-h meas.
Bρ = 1.75±0.02 Tm, ΔBρ/Bρ = 12.7±1.9%
GARIS eff.: 7.8±1.7% for Φ100 mm (σ = 13 nb)
2009/1/20
Periodic Table of D.I. Mendeleev.
Gas-jet eff.: 52±12%
The new superheavy elements
261Rfa
8.28 MeV
257No
8.22, 8.32 MeV
25 s
32
68 s
248Cm(22Ne,5n)265Sg
8 chains
4 chains
265Sga
265Sgb
3.2 s
24 s
8.85
8.66
261Rfb
48 s
1.5 s
265Sgb
265Sgb
18.3 s
8.38
17.2 s
8.29
9 s 16 s
8.85
8.69
261Rf
261Rfb
68 s 3 s
15.9 s
8.57
257No
14 s
265Sg
56.2 s
8.80
261Rfa
257No
8.27
1 chain
33.5 s
8.69
261Rfa
8.31
1 chain
257No
32.2 s
8.18
8.28
8.51, SF
257No
25 s
8.22, 8.32
Düllmann and Tüler:
PRC 77, 064320 (2008).
14 correlations (35 α/fission events) on 265Sg, 261Rf, and 257No
Bρ = 2.07±0.01 Tm, ΔBρ/Bρ = 8.4±1.1%
2009/1/20
Periodic Table of D.I. Mendeleev.
The new superheavy elements
33
Summary I
•
208Pb(58Fe,n)265Hs, 208Pb(64Ni,n)271Ds,209BiPb(64Ni,n)272Rg,
208Pb(70Zn,n)277112,
and 209Bi(70Zn,n)278113 reactions
have been studied.
• Independent confirmations of synthesis of elements 108,
110, 111, and 112
• Optimum reaction energies for (HI,n) reactions were
studied
• New synthesis of an isotope of 113th element
2008/9/17
International School of Nuclear
Physics at Erice
34
Summary II
•
278113
•
278113(a)→274Rg(a)→270Mt(a)→266Bh(a)→262Db(SF)
was produced by 209Bi(70Zn,n) reaction.
• Identification was based on
– connected to the known decays 266Bh(a)→262Db(SF)
– reaction energy systematics
– cross section systematics
• Z & A of 278113 are largest ones among the isotopes
produced by cold fusion reaction.
2008/9/17
International School of Nuclear
Physics at Erice
35
Summary III (preliminary)
•
264Hs(108)
was produced by 207Pb(58Fe,n) and
208Pb(58Fe,2n) reaction.
– confirmation, spectroscopic information of even-even nucleus.
•
263Hs(108)
was produced and identified by 206Pb(58Fe,n),
and reaction208Pb(56Fe,n).
– new isotope
• Off line experiment for the chemistry of superheavy
element coupled to a Recoil Separator using hot fusion
reactions started.
2008/9/17
International School of Nuclear
Physics at Erice
36
2008/9/17
International School of Nuclear
Physics at Erice
37
Future Plan Facility & Device
After the installation of the New Injector for SRC,
existing Linac will be used mostly for the Superheavy research.
We will have two recoil ion separators for the Superheavy research.
Beam time for Superheavy research will increase much.
We should try to utilize fully this situation as efficient as possible.
We will consider to open our RILAC + GARIS facility to users
worldwide both Chemists and Physicists near in future.
We could show the intensities of certain isotopes of heavy elements
to users within a few years.
2009/1/20
Periodic Table of D.I. Mendeleev.
The new superheavy elements
38
Thank you for your attention.
2008/9/17
International School of Nuclear
Physics at Erice
39
2009/1/20
Periodic Table of D.I. Mendeleev.
The new superheavy elements
40
248Cm
2008/9/17
Target 50,000,000 JPY
International School of Nuclear
Physics at Erice
41
・Research in future ーScience of heavy elementsー
1)Searching for new elements
2)Spectroscopic study of heaviest elements
3)Chemistry of heaviest elements
4)Development of the new detectors for SHE study
2008/9/17
International School of Nuclear
Physics at Erice
42
Z=113
year
start
stop
hours
/days
dose/sum
[x 1019]
2003
9/5
12/29
1389/57.9
1.24/1.24
2004
7/8
8/2
526/21.9
0.51/1.75
55
130
45
2005
1/20
1/23
72/3.0
0.07/1.82
52
120
43
3/23
4/22
650/27.1
0.71/2.53
75
100
49
5/19
5/21
48/2.0
0.05/2.58
74
98
48
8/7
8/25
386/16.1
0.45/3.03
63
83
40
9/7
10/20
937/39.0
1.17/4.20
45
59
29
11/25
12/15
469/19.5
0.63/4.83
39
51
25
2006
3/14
5/15
1300/54.2
1.37/6.20
31
40
20
2008
1/9
3/31
1701/70.9
2.28/8.48
23
30
15
590
43
290
Total
s
[fb]
error+
error-
75.3(upper limit)
7477/312
2 events
International School of Nuclear
694/28.9
0.44
Physics at Erice
440
Z=112
2008/9/17
2004
4/2
5/24
Excitation function of
40
208Pb
208Pb(64Ni,n)271Ds
+ 64Ni → 271Ds + n
RIKEN
GSI
35
30
errors
statistical (1s)
s
(pb)
25
20
15
energy loss
in the target
10
5
0
300
305
310
315
320
E(64Ni) /MeV (lab.)
325
← 256Lr ← 260Db ← 264Bh ← 268Mt ← 272111
α３
α５
α４
α２
α１
5
a1
5
t=5.5ms
α１
0
Counts / bin
5
a2
t=30ms
α２
0
5
a3 α３
t=1.3s
0
5
Counts / 100 keV
252Md
α１
0
5
α２
0
5
α３
0
5
t=27s
a4
α４
t=2.2s
0
0
5
5
a5
α５
t=27s
0
0
100ms
2008/9/17
10ms
1s
100s
10000s
α４a4
a5
α５
8
(sec)
Tdecay
International School of Nuclear
9
10
11
Eα / MeV
12
45
Erice
Journal of Physical Society of Physics
Japanat(JPSJ)
Vol. 73, (2004) 1738 - 1744
Excitation function of
209Bi(64Ni,n)272111