j.h. hamilton 1, s. hofmann 2, and y.t. oganessian 3 1 vanderbilt university, 2 gsi 3 joint...
TRANSCRIPT
J.H. Hamilton1, S. Hofmann2,
and Y.T. Oganessian3
1Vanderbilt University,2GSI 3Joint Institute for Nuclear Research
ISCHIA 2014
102
(a) Calculated ground-state shell-correction energy,
(b) partial spontaneous fission (SF), and (c) α-particle half-lives (Smolanczuk, Sobiczewski).
102
184
X117
cold
hot
Ge Detectors
Si Detectors
ToF Detectors
7.5° Magnet
Quadrupoles
Magnets
Beam stop
Electric field
Target wheel
Ion beam
Velocity separator SHIP
SHIP: Separation time: 1 – 2 μs
Transmission: 20 – 50 %
Back ground: 10 – 50 Hz
Energy resolution: 18 – 25 keV
Position resolution 150 μm
Dead time: 3 – 25 μs
The Dubna gas-filled recoil separator DGFRS and detectors are shown.
2094 20
96
92
292116 CN
288114
284Cn
2.75 MeV (escape) 3.3 ms
9.959 MeV 993 ms
172 MeV, uncorrected 50 ms
1
2
sf
02-July-2010, 01:52 h; chain 28.96 MeV, 10.4 mm, strip 4
292116 CN
288114
284Cn
10.624 MeV 76 s
9.895 MeV 1.3 s
197 MeV, uncorrected269 ms
1
2
sf
03-July-2010, 20:01 h; chain 318 MeV, 27.4 mm, strip 2
292116 CN
288114
284Cn
1.4 MeV (escape) 28.8 ms
1.8 MeV (escape) 252 ms
195 MeV, uncorrected121 ms
1
2
sf
07-July-2010, 00:10 h chain 422 MeV, 24 mm, strip 15
292116 CN
288114
284Cn
≈10.6 MeV (stop + box) 11.6 ms
≈10.0 MeV (stop + box) 72 ms
185 MeV, uncorrected 25 ms
1
2
sf
07-July-2010, 09:01 chain 521.0 MeV, 28 mm, strip 12
Experiment SHIP, June 24 – July 26, 2010
48Ca + 248Cm => 292116 + 4n
F 1F 2
2
1
3 1 1 3
B h
2 8 6
2 7 4
2 7 0
6
5M t
2 7 8
R g
2 8 2
4
11 5
11 7
2 90
2 94
D b
1 0 . 2 3 M e V
T K E = 2 1 8 ( 5 ) M e V
11 7
2 97
F 1F 2
2
1
3 1 1 3
2 8 5
R g
2 8 13 8 s
11 5
11 7
2 89
2 93
E = 39 M e V*
5 e v en ts
E = 35 M e V*
1 e v en t
2 4 9 4 8B k + C a
9 .9 5 (4 0 ) M e V
4 5 m s
2 8 . 3 s
1 .3 m in
0 .7 4 s
1 1 .0 s
3 3 . 4 h
7 .4 m in
1 3 s
8 .1 s
1 .0 s
0 .0 2 3 s
1 1 2 m s
9 .6 3 (1 0 ) M e V
9 .5 6 M e V
8 .8 0 (1 0 ) M e V
8 .4 3 M e V
9 .0 0 (1 0 ) M e V
9 .4 3 M e V
9 .5 5 (1 9 ) M e V
9 .1 4 M e V
1 0 . 8 1 (1 0 ) M e V
1 1 .0 0 M e V
T K E = 2 1 9 ( 5 ) M e V
1 0 . 3 1 (9 ) M e V
1 0 . 4 8 M e V
7 .9 s
0 .3 2 s
2 1 m s
1 0 m s
0 .2 2 s
1 .2 s
9 .7 4 (8 ) M e V
9 .4 8 (1 1 ) M e V
1 1 .0 3 (8 ) M e V
1 1 .2 6 M e V
9 .9 6 M e V
11 7
2 97
1 6 sblack - experiment,blue – theory
Note the good agreement of the macroscopic-microscopic calculated alpha energies (blue) and our experimental ones (black).
mm3.03.19
70 days run
Note decay not SF as for 281Rg
Definitive evidence for elements 113, 115
in the reaction 243Am + 48Ca
Two sets of experiments from November 2010 – February 2012.Five different beam energies were used.
27 28
2 3 4
Since PRL 2012
Cross bombardment check
New 249Bk target for Dubna and GSI 2012, 2013
Dubna
48Ca + 249Bk
11 new events of 293117 and 3 new events of 294117.Totals 16 events of 293117 and 4 of 294117.
One new 48Ca + 249Cf 294118 + 3n
GSI
48Ca + 249Bk
Confirmed 294117.
50Ti + 249Bk 296119 + 3n
No events seen; s less than 70 femtob after 6 months.
D. Rudolph, Lund University APSORC 13, Kanazawa, Japan, September 2013
Alpha-Gamma Spectroscopy on 288115
22 chains (out of 30) of ours are compatible with the
31 chains (out of 37) associated with the 3n channel 288115 by Oganessian et al.
8.73-9.1512.0( )
288115
284113
280Rg
276Mt
272Bh
268Db
9.17-9.95 0.54( )/6( )
9.09-9.873.6( )
9.97(5),9.81(7)0.97( )
10.33-10.580.171( )
27( ) h
DGFRS
4228
2517
96
82
149
3121
54
8.55-9.099.2( )
288115
284113
280Rg
276Mt
272Bh
268Db
9.43-9.89 0.75( )
9.25-9.926.4( )
9.10-10.110.81( )
10.29-10.560.150( )
26( ) h (and γ rays!)
TASCA
4328
2315
2113
2515
3118
75
D. Rudolph et al., PRL 111 (2013) 112502
s
s
s
s
s
Partial half-lives for SF vs. N. solid symbols and crosses denote even-even, open symbols – even-odd nuclei. Solid lines are drawn through the experimental points of even-even nuclei. The dashed lines are calculated TSF(th) .
Radioactive properties:(a) a-particle energies Q a for odd-Z nuclei agree with the systematics and have intermediate values between neighboring even-Z nuclei.(b) a-particle energies of the Z=107 and Z=109 isotopes as well as their behavior vs neutron number are in agreement with what is observed for the neighboring lighter previously known nuclei.(c) Decrease of Qa values with approaching N=184 magic number -- increase of stability.
Radioactive properties:increase of stability with approaching N=184 magic number
Rg112113
114
117
115
118
116
160 162 164 166 168 170 172 174 176 178 180 182 184152 158156154
BhHs
MtDs
NoMdFmEsCf150
NoMdFmEsCf
Sg
Z = 114
aaa
a
112/2859.1529 s
A/Z
T1/2
E (MeV)
EC
-
SF
aa10.02 9.94
10.84 10.74
9.54
9.30
10.00
10.4610.59
10.12
9.75
9.71
9.02
10.37
10.33
7.1 ms
32 ms 87 ms
18 ms
0.10 s
0.19 s
0.17 s
0.72 s
9.8 s
29 h
9.7 ms
0.48 s
97 ms0.82 ms
3.6 s
0.20 s
1.9 m
0.48 s 0.80 s0.13 s10.19
3.8 s
48 238 249Ca + U... Cf
8.54
9.70
18 s10.66
0.89 ms11.65
10.5461 ms
Db
LrRf
-7
-6
-5
-4
Esh=-3
10.630.07 s
10.694 ms
10.0.4 s
8.931 m
20 m 1.2 h
9.822.6 s
9.1529 s
11 s
1.3 h
Neutron number
Chart of nuclidesPr
oton
num
ber
14 ms11.03 10.8180 ms
10.31 9.95220 ms 16 ms
9.745.5 s 9.6320 s
26 s 9.000.5 s
9.558 s
8.8050 s
23 h
281111(N=170) lies in the “critical” region between the stabilizing effect of the N=162 and 184 neutron shells.
The high hindrance caused by the odd proton does not save 281111(N=170) from SF because of the weakening of the above neutron shells.
282111(N=171) has an extra unpaired neutron that further hinders SF relative to alpha decay. Thus this nucleus undergoes alpha decay.
s less than 70 femtob after 6 months at TASCA.
Warmest best wishes for health and long life to Prof. Aldo Covello
Thank you.