the pecul i arit ies of the production and decay of superheavy nuclei
DESCRIPTION
99 –th Session of the JINR Scintific Council 19 - 20 January 2006. The pecul i arit ies of the production and decay of superheavy nuclei. M.G.Itkis. Flerov Laboratory of Nuclear Reactions, JINR, Dubna, Russia. The dynamics of the fusion-fission of superheavy nuclei - PowerPoint PPT PresentationTRANSCRIPT
The peculiarities of the production
and decay of superheavy nuclei
M.G.Itkis
Flerov Laboratory of Nuclear Reactions, JINR, Dubna, Russia
The dynamics of the fusion-fission of superheavy nuclei
Experimental results. The peculiarities of the observables, the signatures of the Fusion-Fission/Quasi-Fission processes, multimodal fission phenomena
The recent results on synthesis of superheavy nuclei
The perspectives of the “hot” fusion reaction for the production of superheavy nuclei
Shape evolution in Fusion-Fission reactions
Elastic scattering Coulomb excitation Quasi-elastic scattering Deep-inelastic scattering Incomplete pulse transfer Fast-fission Quasi-fission Fusion → CN → Fission Fusion → CN → de-excitation (n,)→ ER
In dependence on impact parameter and projectile energy :
Kinematics coincidence method. Double arm time-of-flight spectrometer CORSET
Experimental results
The sharp change of the MED triangular shape for the reaction 48Ca+208Pb, where Fusion-Fission process dominates, to the Quasi-Fission shape of MED for the 286112-296116 nuclei.
The wide two-humped mass distribution with high peak of heavy fragment near double magic lead (MH208) for the Quasi-Fission process.
In spite of the dominating role of the Quasi-Fission process for these reactions we assume that in the symmetric region of the fragment masses (A/220) FF process coexists with QF.
The Fusion-Fission mass distribution is asymmetric in shape with mass of the light fragment ML132-134 amu ( see on the framings)
Mass-energy distributions of the fission fragments of 256102- 296116 nuclei produced in “hot” fusion reactions with 48Ca-projectiles
E* 33 MeV
Mass Asymmetry in Low Energy Fission of Superheavy nuclei
E*33-40 MeV
Hot fusion reaction48Ca + 248Cm 296116
Fusion-Fission DynamicsM.G.Itkis, Yu.Ts.Oganessian, V.I.Zagrebaev, Phys.Rev.C65,2002, 044602
To
tal k
ine
tic e
ne
rgy
(Me
V)
Mas
s a
sym
me
try
(A1-A
2)/
(A1+
A2)
Fragment mass number (u)Y
ield
,%
Cold fusion reaction
Neutron and -emission as probe FF/QF
Neutron multi-detectors “DEMON” with trigger of fission fragments “CORSET”
Two-dimensional matrixes TKE-Mass, Mass Yields, neutron multiplicities (pre, post and tot) for the reactions 48Ca+208Pb and 48Ca+238U
Total neutron multiplicities as function of atomic number of compound nuclei produced in the reaction with 26Mg, 48Ca and 58Fe-projectiles
Two-dimensional matrixes TKE-Mass, Mass Yields, neutron and -multiplicities for the reaction with 48Ca-projectiles on the targets 208Pb,238U, 244Pu,248Cm
Capture and Fusion-Fission Cross Sections
The perspectives of the “hot” fusion reaction for the production of superheavy nuclei
Shell effects manifestation
QF/
cap (
%)
Natural occurrence of Ca isotopes (in %):
40Ca – 96.9442Ca – 0.64743Ca – 0.13544Ca – 2.08646Ca – 0.004
48Ca – 0.187 beam tim e - 4000 h/y
beam intensity - 4 - 8 .10 /s
12
C onsum ption of m g/h 48 С а (68% ) - 0.5
Isotopes:
+U , P u , A m , C m[233 , 238 ] [242, 244] [245, 247], [249][243 ] C f Z = 112 - 118 48 C a
x 400
→ Ca5+
isotope productionhigh flux reactors
(Oak Ridge, Dimitrovgrad)
isotope enrichment 98-99%S-2 separator
(Sarov)
technology of the target preparation – 0.3 mg/cm2
Separation of super heavy nuclei and detection of their radioactive decays
now: DGFRS
D u bn a G as F illed R ec o il S e p a ra to r
v (A=48) = 0.11 cq = 16.5+
v (A=288) = 0.017 cq = 6.2+
- -SF
0 .1
104n
A = 2 8 8
5n[2 8 7 ]
3n[2 8 9 ]
5
0 .5
B C
Cro
ss s
ectio
ns (
pb)
1
P u -ta rg et 2 4 4
30E xcita tion energ y (M eV )4035
35
45 50 55
P u -ta rg et 2 4 2
B C
4n[2 8 6 ]
3n[2 8 7 ]
10
5
0 .5
0 .130
E xcita tion energ y (M eV )
Cro
ss s
ectio
ns (
pb)
4 0 45 50 55
1
U -ta rge t 2 3 8
B C
4n[2 8 2 ]
3n[2 8 3 ]
- -SF-S F -SFand SF
- -SF
-SFand SFSF
Isotope charge (Z) and mass (A) identificationsobtained by the measurements of neutron evaporation cross sections vs. excitation
energy of compound nucleus
2n[288]
-SF
Decay Chains Observed in 243Am + 48Ca Reaction
10.51 MeV
10.4 MeV
E = 248 MeV L
a) b)
E = 253 MeV L
11.0 MeV 9.1 MeV
9.72 MeV
9.65 MeV
80.3 ms
0.376 s
3.146 s
24.103 s
1.055 s
1 8 . 6 m m
1 8 . 5 m m 2 3 . 3 m m 1 8 . 8 m m
2 1 . 3 m m
1 8 . 4 m m
1 8 . 8 m m
1 8 . 5 m m
115
R R R
113
111
Mt
Bh
288
284
280
276
272
9. MeV 02. s2 964. m m 2 3 6
9.7 MeV 6. s10 599. m m 2 3 7
10.38 MeV 18. ms6
. s1 196
. s0 249
. m m 2 3 7
115
113
111
Mt
Bh
288
284
280
276
272
. s15 388. m m 1 8 1
9.7 MeV 6
9.7 MeV 4
. s1 723
. s1 834
. m m 1 8 1
. m m 1 9 2
10 00 . MeV
10. MeV 50 ms280
. s0 517
. m m 1 8 5
. m m 1 8 7
115
113
111
Mt
Bh
288
284
280
276
272
SF140 MeV 16 98. h1 7 8. m m
Db268
5
4
3
2
1
5
4
3
2
1
5
4
3
2
1
T h e b e a m w a s s w i t c h e d o f f
9.23+_0.61 MeV
0.376 s
28.70 h 1 8 . 2 m m
SF
Db268
205 MeV
9. +_0.61 MeV 48
9. +_0.61 MeV 80
SF
2 . h3 54 2 3 . 2 m m
Db268
20 MeV0
10. MeV04
8.97 MeV
1 7 . 9 m m
105.96 min
1
12.2 MeV 1 8 . 0 m m
R
10.33 MeV 14.0 ms
7 . 7 m m 1
10.59 MeV
10. MeV 12
46. ms6
0.147 s
. 6 m m 1 7
. 7 m m 1 7
115
113
111
Mt
287
279
275
10.37 MeV . s0 245
SF
Db267
206 MeV
Bh271
283
1 0 4
11 0
11 4
1 2 0 -d e c a y
N e u tro n n u m b e r
prot
on n
umbe
r
1 s
1 m s
1 s
o d d -o d d
1 5 0 1 7 0 1 8 0 1 9 0
1 0 s9
1 0 s3
1 0 s6
_
-d e c a y
T =1.5 s1/2
Bh
Mt
111
Db
209 64Bi+ Ni
115
243 48Am+ Ca
113
111
Mt
Bh
Rf
T 1 d1/2
Db
odd-odd
1 1 4
2 8 6
1 1 6
2 9 0 1 1 . 8 0 +_ 0 . 5 3 M e V
0 . 8 5 m s 1 3 . 6 6 M e V
1 7 .5 m m
1 1 81 1 8
2 9 4 2 9 7
M a r c h 1 9 , 2 0 0 5
0 7 : 4 3
S F
1 1 2
2 8 2 1 0 . 1 6 M e V
0 . 1 5 s
1 6 . 8 m m
2 0 2 ( 1 5 1 + 5 1 ) M e V
2 . 7 m s
1 6 . 9 m m
1 0 . 8 0 M e V
0 . 1 m s
1 7 . 0 m m
1
2
3
Synthesis of Element 118 in 249Cf + 48Ca Reaction
S F
M arch 19 , 2002 05:28
11 .6 5 M e V 2 .5 5 m s 9 .0 m m
1 3 .2 2 M e V 8 .9 m m
2 0 7 (1 8 8 + 1 9 ) M e V5 1 6 .6 m s9 .4 m m
1 0 .7 1 +- 0 .1 8 M e V4 2 m s1 5 .1+_ 7 .3 m m
11 82 9 7
11 82 9 4
11 62 9 0
11 42 8 6
1
2
2002
20052002 - 2004
3 n2 n
118294
118295
245Cm+48Ca
242Pu+48Ca
238U+48Ca 10.02 MeV
26.3 ms
0.68 s
116
114
112
291
287
283
1
2
SF(~90%)
SF(~30%)
10.74 MeV
970. MeV
7.87 s
0.28 s
110
108
279
275
3
49.5 MeV
8.53 MeV
0.3 s
2.80 min104267
5
6 9.30 MeV
1.84 h
SF
10.16 MeV
6.23 ms
0.55 s
116
112
290
282
1
2
1.0 ms
SF
SF(~60%)
10.5 MeV8114
286
106271
neutron number
111112113
114
117
115
118
116
160 162
164 166 168 170 172 174
176 178 180 182 184
152 158156154
Mt 266
Db 262 Db 263
Sg 266
Db 258Db 256 Db 260Db 257
Rf 260 Rf 261 Rf 262 Rf 263Rf 259Rf 256Rf 255 Rf 258
Bh 261 Bh 262
Rf 257
Db 261
Sg 260 Sg 261 Sg 263Sg 259
Bh 264BhHs
Ds
Sg 258
Lr 259
No 258
Lr 260
No 259
Lr 261 Lr 262
No 262No 260
Lr 258
No 257
Lr 255
No 254
Lr 254
No 253
Lr 257
No 256
Lr 256
No 255
Md 257
Fm 256
Md 258
Fm 257
Md 259 Md 260
Fm 258 Fm 259
Md 256
Fm 255
Md 253
Fm 252
Md 252
Fm 251
Md 255
Fm 254
Md 254
Fm 253
Es 255 Es 256Es 254Es 251Es 250 Es 253Es 252
Cf 255 Cf 256Cf 253Cf 250Cf 249 Cf 251 Cf 252 Cf 254
110/273110/271
111/272
CHART OF THE NUCLIDES
NoMdFmEsCf
pro
ton
n
um
ber
150
DbRfLrNoMdFmEsCf
Z = 114
108Hs 267Hs 265Hs 264
a
aa
aa
a
110/270
Hs 266
Sg 262
112/2859.1539 s
Z/A
T1/2
E (MeV)
110/269
Mt 268
EC
-
SF
112/277
110/267
MtHs 269 Hs 270
Sg 265Sg
aaa
aa
aa
aa
aa
a
aa
a aa
aaaa
108/275
110/279
106/271
112/284112/282
114/286114/28710.01
114/2889.95
116/290
115/288115/287
113/284113/283
111/280
109/276
107/272
111/279
109/257
116/29110.85 10.74
112/285
110/281
114/2899.82
9.169.54
9.30
8.53
10.00
10.4610.59
10.12
9.75
9.71
9.02
10.37
10.33
105/268
15 ms
32 ms 87 m s
6.3 m s
0.1 s
0.15 s
0.17 s
0.72 s
9.8 s
16 h
9.7 m s
0.48 s
0.1 s0.5 m s
3.6 s
0.18 s
2.4 m in
9.6 s
34 s
0.56 s 0.63 s 2.7 s0.16 s10.20
112/2834.0 s
a116/29210.6616 ms
107/217
116/29353 ms
1.8 ms118/29411.65
105/2671.2 h
10.53
9.70
104/268104/2672.3 h
48 238 249Ca + U.... Cf
208 50 70Pb + Ti.... ZnNumber of
observed decays
Z = 118 3 116 23
114 45 112 52
The formation of 294116 in the reactions with 48Ca and 50Ti-ions
Mass-energy distributions of the fission fragments
Capture cross sections for the reactions 50Ti+244Pu and 48Ca+246Cm
N=174 N=182 N=184 N=184
Reactions of the production of 116-122 elements with 58Fe and 64Ni-projectiles
1 50 1 60 1 70 1 80 1 901 40
1 5
2 0
1 0
-5
-1 0
11 6
11 6
11 8
11 2
11 2
11 4
11 4
11 0
11 0
1 0 8
1 0 8
- d ecay
fa s t ch em istry ava ilab le
D efo rm edS he ll
S ph erica lS he ll
A ge o f the E arth
s ta b len u c le i
1 50 1 60 1 70 1 80 1 901 40
1 5
2 0
1 0
5
0
-5
-1 0
11 6
11 6
11 8
11 2
11 2
11 4
11 4
11 0
11 0
1 0 8
1 0 8
N eu tro n n u m b er
- d ecay
fa s t ch em istry ava ilab le
D efo rm edS he ll
S ph erica lS he ll
Log
T (
seco
nds)
A ge o f the E arthT h e o ry a n d E x p e r im e n t
s ta b len u c le i
th e e x p e r im e n ta ll im it o f th e se a rc h fo r S H E in N a tu re
108 y
105 y
1 y
1 d
the search for SHE in Cosmic rays
H
1
Li
3
Be
4
Na
11
M g
12
K
19
Ca
20
Sc
21
104
Ti
22
V
23
Cr
24
M n
25
Fe
26
Co
27
Ni
28
Cu
29
Zn
30
1
2
3 4 5 6 7 8 9 10 11 12
13 14 15 16 17
18
1
2
3
4
5
6
He
B
Al Si P S
ONC F
Cl Ar
Ne
7105 106 107
72 73 74 75 76 77 78 79 80 81 82 83 84 85 8655 56
87 88
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
31 32 33 34 35 36
Rf Db Sg Bh
Rb Sr Y Zr Nb M o Tc Ru Rh Pd Ag Cd In Sn Sb Tc I Xe
Cs Ba Hf Ta W Re O s Ir Pt Au Hg Ti Pb Bi Po At Rn
Fr Ra
G a G e As Se Br Kr
108 109 110 111 112 113 115114 116 117 118
Hs M t
Dar
ms-
tad
tiu
m
Ds Rg
117
Periodic Table of the Elem ents
Search in NatureSearch in Nature
Chemical properties (relativistic effect)Chemical properties (relativistic effect)
Astrophysics (search for SHE in cosmic rays)Astrophysics (search for SHE in cosmic rays)
Nucleosynthesis (test of the r-s process) Nucleosynthesis (test of the r-s process)
Atomic physics (structure of SH-atoms)Atomic physics (structure of SH-atoms)
Elements with Z ≥ 120
Flerov Laboratory of Nuclear Reactions of JINR
…in February
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