the superheavy element programme at tasca @ gsi/fair · chemistry a. yakushev et al., inorg. chem,...

The Superheavy Element Programme at TASCA @ GSI/FAIR

Ulrika Forsberg on behalf of the TASCA collaboration

September 29, 2016NUSTAR Week, York

Superheavy elements

new sub-collaboration in

NUSTAR@FAIR

Outline

• Superheavy elements (SHE)

• The TASCA separator

• Experiments and main results

• Plans for the future

Periodic table

104Rf

105Db

106Sg

107Bh

108Hs

109Mt

110Ds

111Rg

112Cp

113Uut

114Fl

115Uup

116Lv

117Uus

118Uuo

Superheavy elements: Z ≥ 104

100

120

114

162

184

108

152

Cn

N

Z

DsMt

HsBh

a

b +

EC

SF

b-

Rg

172 Mic-Mac (A. Sobiczewski)

RMF (Zhang)

113

117118

Lv115

Fl

Courtesy of Ch.E. Düllmann 5

Superheavy Elements: Z ≥ 104

S.G. Nilsson

et al.(1969)

100

120

114

162

184

108

152

Cn

N

Z

DsMt

HsBh

a

b +

EC

SF

b-

Rg


RMF (Zhang)

113

117118

Lv115

Fl

6

Superheavy Elements

Courtesy of Ch.E. Düllmann

1 atom s-1

1 atom d-1

100

120

114

162

184

108

152

Cn

N

Z

DsMt

HsBh

a

b +

EC

SF

b-

Rg


RMF (Zhang)

113

117118

Lv115

Fl

7

Mass measurements M. Block et al., Nature 463 (2010) 785

E. Minaya Ramirez et al., Science 337 (2012) 1207

ChemistryA. Yakushev et al., Inorg. Chem,

Nuclear structure and X-raysD. Rudolph et al., PRL 111 (2013) 112502

Laser spectroscopyM. Laatiaoui et al., to be published

Superheavy Elements – Highlights from the past years


Elements confirmedJ. Khuyagbaatar et al., PRL 112 (2014) 172501

S. Hofmann et al., EPJA 48 (2012) 62

New element searchesCh. E. Düllmann et al., in preparation

100

120

114

162

184

108

152

Cn

N

Z

DsMt

HsBh

a

b +

EC

SF

b-

Rg


RMF (Zhang)

113

117118

Lv115

Fl

8

Superheavy Elements


The TASCA Collaboration

10Courtesy of Ch.E. Düllmann

LBNL/UCB Berkeley (USA) U Jyväskylä (Finland)

LLNL Livermore (USA) U Oslo (Norway)

Vanderbilt U (USA) Chalmers U Gothenburg (Sweden)

ORNL Oak Ridge (USA) PSI Villigen/U Berne (Switzerland)

U Liverpool (UK) ITE Warschau (Poland)

U Surrey (UK) U Lund (Sweden)

SINP Kolkata (India) IIT Roorkee (India)

IMP Lanzhou (China) ANU Canberra (Australia)

RIKEN Wako (Japan) JAEA Tokai (Japan)

TASCA

Beam

TargetDipole

Q1Q2

Search for element 120

Fl

113

117

118

Lv

115

119

120

102 104 106 108 110 112 114 116 118 120

1E-15

1E-14

1E-13

1E-12

1E-11

1E-10

1E-9

1E-8

1E-7

1E-6 Projectile Target48

Ca,...,70

Zn + 208

Pb/209

Bi13

C,...,26

Mg + 238

U...249

Bk48

Ca + 238

U,...,249

Cf

cro

ss

sec

tio

n /

ba

rn

atomic number Z

Synthesis of superheavy elements

Warm fusion

(48Ca + actinides)


249Cf: heaviest

target 48Ca-era ends 20

98

How to synthesize element 120?

14

249Cf + 50Ti 299120



Target Chamber

side view

DSSSD State-of-the-Art Stop Detector Array

48 mm

144 mm

6900 pixels

Electronics

Analogue electronics + digital electronicsFEBEX

Developed at GSI-EE

60 MHz dead-time free ADC sampling

www.gsi.de

Electronics

Analogue electronics + digital electronicsFEBEX

time (16.7ns/channel)

Sig

nal he

ight (a

rb. units)

α1

α2 FEBEX:

Can resolve events

separated by ~100 ns.

Fast decays from E120 can be measured

Two fast α decays of ~5 MeV cannot be confused with one α decay of ~10 MeV.

102 104 106 108 110 112 114 116 118 120

1E-15

1E-14

1E-13

1E-12

1E-11

1E-10

1E-9

1E-8

1E-7


Ca,...,70

Zn + 208

Pb/209

Bi13

C,...,26

Mg + 238

U...249

Bk48

Ca + 238

U,...,249

Cf

cro

ss

sec

tio

n /

ba

rn

atomic number Z

TASCA Search for element 120 in 50Ti + 249Cf reaction

2011:

Z=12050Ti + 249Cf

39 d200 fb


Search for E119

Reaction: 50Ti + 249Bk → 299-x119 + xn22 97

Fl

113

117

118

Lv

115

120

119

249Cf 98

Production and separation: Target production:

102 104 106 108 110 112 114 116 118 120

1E-15

1E-14

1E-13

1E-12

1E-11

1E-10

1E-9

1E-8

1E-7


Ca,...,70

Zn + 208

Pb/209

Bi13

C,...,26

Mg + 238

U...249

Bk48

Ca + 238

U,...,249

Cf

cro

ss

sec

tio

n /

ba

rn

atomic number Z

Cross Sections in Hot / Cold / 48Ca Induced Fusion Reactions

Z=11950Ti + 249Bk

70 fb


E117 confirmation

Reaction: 48Ca + 249Bk → 297-x117 + xn20 97

Fl

113

117

118

Lv

115

120

119

Element 117 among Top Ten Physics News Stories in 2014

Every year, APS selects Top Ten PhysicsNews Stories, which received largestpublic attention. The 2014 list includeshighlights like

•intergalactic neutrinos from IceCube,

•Rosetta/Philae comet mission

•blue LEDs (physics nobel prize 2014)

•our Element 117

•...

J. Khuyagbaatar et al., Phys. Rev. Lett. 112 (2014) 172501


E114 & E113 Chemistry

Fl

113

117

118

Lv

115

120

119


Ge cluster

E115 trajectory

243Am target


COMPACT

A. Yakushev


A. Yakushev et al., Inorg. Chem. 53, 1624 (2014)

Results from first E114 exp: … and subsequent exp:

Stay tuned!

E115 Fingerprinting 48Ca-induced reactions give chains that

end by spontaneous fission

Courtesy of Ch. E. Düllmann

Superheavy elements, Z ≥ 104

Need direct measurement of atomic numbers!

Yu.Ts.Oganessian, J. Phys.G34, R165 (2007) etc.

Fl

113

117

118

Lv

115

120

119

→ X-rays

α

γ-rays orinternal conversions

100-500keV

Look for characteristic X-rays emitted in coincidence with α decays!

E115 Fingerprinting

Energy depends on proton number!

TASCA

CLUSTER

CLOVER

CLOVER

CLOVER

CLOVER

L.-L. Andersson et al., NIM A622, 164 (2010)

10.42(1) MeV0.437 s

268Db

272Bh

276Mt

280Rg

284113

288115

9.96(1) MeV0.965 s

9.75(1) MeV11.4 s

9.87(1) MeV 1.69 s

9.07(1) MeV4.05 s

161 MeV134.4 h

10.34(1) MeV1.46 s

281Rg

285113

289115

9.89(1) MeV0.0262 s

220 MeV0.432 s

10.64(5) MeV 0.0676 s

267Db

271Bh

275Mt

279Rg

283113

287115

10.23(1) MeV0.0684 s

1.33(1) MeV0.0161 s

10.33(1) MeV 0.0513 s

8.76(5) MeV 2.60 s

191 MeV30.6 min

4n

2n

3n

1 22 7 short

= detected in beam off period

?

Experiment30 chains detected in 18 days

3n ?

288115α1

284113

280Rg

α2

276Mt109

272Bh107

111

268Db105

α3

α4

α5

10.29(1) MeV 0.366 s

9.24(1) MeV 0.935 s

9.77(1) MeV11.1 s

0.825(3) MeV (escape) 0.515 s

9.06(1) MeV 15.3 s

FISSION, 197 MeV, 17.4 hours, 4 γ

Photons: 136(1), 167(1) keV

ExperimentPotential X-rays

Kα2 Kβ Bh (Z=107)

Difference between neighbouring Z: 3-4 keV

Accurate to 0.5%T.A. Carlson et al., Nucl. Phys. A 135, 57 (1969)

Experiment

Special thanks to …

111, 112502 (2013)

ENSARUNILAC

… among the Top Ten APS Physics Newsmakers of 2013!

E115 is everywhere…

10.42(1) MeV0.437 s

268Db

272Bh

276Mt

280Rg

284113

288115

9.96(1) MeV0.965 s

9.75(1) MeV11.4 s

9.87(1) MeV 1.69 s

9.07(1) MeV4.05 s

161 MeV134.4 h

10.34(1) MeV1.46 s

281Rg

285113

289115

9.89(1) MeV0.0262 s

220 MeV0.432 s

10.64(5) MeV 0.0676 s

267Db

271Bh

275Mt

279Rg

283113

287115

10.23(1) MeV0.0684 s

1.33(1) MeV0.0161 s

10.33(1) MeV 0.0513 s

8.76(5) MeV 2.60 s

191 MeV30.6 min

4n

2n

3n

1 22 7 short

= detected in beam off period

?

Experiment30 chains detected in 18 days

3n ?

TASC

AB

GS

Du

bn

a10

4

115

113

Rg

115

113

E3,t3

E2,t2

E1,t1

E1,t1

E2,t2

U. Forsberg et al., NPA (2016)

TASC

AB

GS

Du

bn

a10

4

115

113

Rg

115

113

E3,t3

E2,t2

E1,t1

E1,t1

E2,t2

NOT a set of chains following the same decay path! (<1% error risk)

E115-E117

289115

285113

281Rg

293117

289115

281Rg

285113

0.32( ) s

1.7( ) s

7( ) s

0.25( ) s

2.7( ) s

18( ) s

127

64

3

11

2

6

47

612

16

14

”Cross bombardment”:same isotope seen in different reactions

NOT a set of chains following the same decay path! (<<1% error risk)

Open for public review until November 8 2016

ExperimentFuture

Since UNILAC is not suited for simultaneousacceleration of beams for SIS100 and SHE research…

ExperimentFuture

New dedicated sc cw LINAC is planned!

Energy: 3.5-7.5 MeV/u

Uncertainty: <3 keV/u

Duty cycle: 100%

Length: 13.5 m

ExperimentFuture

W. Barth et al. Proc. IPAC 2013

Step 1: Build demonstrator unit

ExperimentFuture

Nov. 19, 2015: Delivery of cryostat to GSI

ExperimentFuture

ExperimentFuture

Superheavy element research:• new elements• nuclear spectroscopy• laser spectroscopy• X-ray fingerprinting• chemistry• mass measurements• …

the superheavy element programme at tasca @ gsi/fair · chemistry a. yakushev et al., inorg. chem,...

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