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.