GSI Helmholtzzentrum für Schwerionenforschung GmbH

Chemical Study of Element 113 (Nihonium) at GSI Alexander Yakushev for E113 chemistry collaboration at TASCA

GSI Helmholtzzentrum für Schwerionenforschung GmbH Nihonium – a proposed name for element 113

... For the element with atomic number 113 the discoverers at RIKEN Nishina Center for Accelerator-Based Science (Japan) proposed the name nihonium and the symbol Nh. Nihon is one of the two ways to say “Japan” in Japanese, and literally mean “the Land of Rising Sun”. The name is proposed to make a direct connection to the nation where the element was discovered. ...

GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 2 Nihonium chemistry experiment at GSI

GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 3 Collaboration

Spokesperson: A. Yakushev (SHE Chemistry, GSI) Co-spokesperson R.-D. Herzberg (University of Liverpool (UK), responsible for ENSAR cooperation)

A. Yakushev1,2, Ch. E. Düllmann1,2,3, L. Lens1,3, M. Asai4, M. Block1,2,3, H. Brand1, H. David1, J. Despotopulos5, A. Di Nitto1,3, K. Eberhardt2,3, U. Forsberg6, P. Golubev6, M. Götz1,2, S. Götz1,2, H. Haba7, L. Harkness-Brennan8, R.-D. Herzberg8, F. P. Heßberger1,2, D. Hinde9, J. Hoffmann1, A. Hübner1, E. Jäger1, J. Khuyagbaatar1,2, D. Judson8, B. Kindler1,Y. Komori7, J. Konki10, J. V. Kratz3, J. Krier1, N. Kurz1, M. Laatiaoui2, S. Lahiri11, B. Lommel1, Ch. Lorenz6, M. Maiti12, A. K. Mistry2, Ch. Mokry2,3, Y. Nagame4, J. P. Omtvedt13, P. Papadakis10, V. Pershina1, D. Rudolph6, J. Runke1,3, I. Rusanov1, L. G. Sarmiento6, T. Sato4, P. Scharrer1,2, B. Schausten1, M. Schädel1, J. Steiner1, P. Thörle-Pospiech2,3, N. Trautmann3, K. Tsukada4, J. Uusitalo10, A. Ward8, M. Wegrzecki14, N. Wiehl2,3, E. Willams9, V. Yakusheva1

1GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany 2Helmholtz Institute Mainz, Mainz, Germany 3Johannes Gutenberg University Mainz, Germany 4Japan Atomic Energy Agency, Tokai, Japan 5Lawrence Livermore National Laboratory, Livermore, CA, USA 6Lund University, Sweden 7RIKEN, Japan 8University of Liverpool, UK 9Australian National University, Canberra, Australia 10University of Jyväskylä, Finland 11Saha Institute of Nuclear Physics, Kolkata, India 12Indian Institute of Technology, Roorkee, India 13University of Oslo, Norway 14Institute of Electron Technology, Warsaw, Poland.

GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 4 Relativistic Effects on Valence AOs of SHEs (eV)

10 2 2 1 2 2 ...... 2 6 d2s2 ...... d s s p1/2 s p1/2 s p 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 0 7p3/2

-10 7p

7p1/2 -20 7s , eV

E -30 7s1/2

-40 6d5/2

6d3/2 -50 6d -60

Courtesy V. Pershina

GSI Helmholtzzentrum für Schwerionenforschung GmbH Adsorption of Cn, E113 and Fl on Gold

Courtesy V. Pershina M-Aun binding energies

3 top bridge hollow1 hollow2

2.5

2 Pb

1.5 exp. , eV, E 1 114 M position, n Eb, eV ∆Hads, eV Ref. (exp.) Hg 0.5 112 Hg bridge n=94 0.56 0.92 Eichler

0 +0.4 n=1 n= 38 n=95 n= 38 n=94 n= 35 n=120 n=107 Cn hollow n=107 0.46 0.54 -0.03 Eichler

-0.5 Pb bridge n=94 2.40 2.43 Haennsler +0.5 114 bridge n=94 0.71 0.36 -0.1 Eichler −∆H kJ/mol ≥≥≥ 0.5 Yakushev ads, 159 Tl bridge n=16 2.65 2.48 Serov 113 bridge n=16 1.34 (1.65) - 68 52 like highest occupied AO Z [Pershina, Anton, Jacob, JCP, 2009] 112 113 114 GSI Helmholtzzentrum für Schwerionenforschung GmbH Theoretical predictions for Nh adsorption

Quartz Gold

2 1 Tl: 6s 6p1/2 2 1 Nh: 7s 7p1/2

Tl: ≡Si(OH)(OTl) −∆Hads = 150.2 kJ/mol Tl: (Au)nTl −∆Hads = 238 kJ/mol [V. Pershina, priv. com. (2016)] [V. Pershina, priv. com. (2016)] exp. [P. Steinegger et al.. −∆Hads = 158 kJ/mol exp. [A .Serov et al. Radiochim. −∆Hads = 279 kJ/mol J. Phys. Chem. C 120 (2016)] Acta 101 (2013)]

Nh: ≡Si(OH)(ONh) −∆Hads = 57.8 kJ/mol Nh: (Au)nNh −∆Hads = 115 kJ/mol [V. Pershina, priv. com. (2016)] [V. Pershina, priv. com. (2016)]

(Au)nNh −∆Hads = 96-116 kJ/mol [A. Rusakov et al. Centr.Eur.J.Phys. 11 (2012)] Members of the group 13 – Tl and Nh – are most reactive between groups 12 to 14 GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 7 Gas chromatography of thallium offline online

COMPACT II (Au) COMPACT I (SiO ) 2

1400 70000 Hg Gold 1200 Tl 60000

1000 50000

40000 800

E v e n ts E v e n ts 30000 600

400 20000

200 10000

0 0 0 10 20 30 0 10 20 30

Detector # Detector # Quartz TlOH Flush out efficiency

Tl Hg <20% ~60%

GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 8 First attempts on Nh chemistry at FLNR

Detection efficiency is ≤ efficiency of COLD No 2- and 3-member decay chains were found

NR for short incomplete chains is too high

GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 9 First attempts on Nh chemistry at FLNR

Detection efficiency is ≤ efficiency of COLD No 2- and 3-member decay chains were found

NR for short incomplete chains is too high

Chain identification is questionable Overall efficiency is unknown However, chemical behavior in detector looks reasonable

GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 10 Chemistry without preseparation

ααα ααα NR( 1- 2) Nα>9.2 MeV ? NSF ? α ααα NR( 1- 2) >> 1 Transport time and α NR( 2-SF) transport yield [R. Eichler et al. Radiochim. Acta 98 (2010)] are not measured Real detection efficiency?

3.8x10E18 8x10E18 detectors 1-27 single detector

V(RC)=21 cm3, + quartz wool plug + 6 m cappilary

[D. Wittwer et al. NIM B 268 (2010)] [S.N. Dmitriev et al. Mendeleev communications 24 (2014)] GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 11 Experimental setup at TASCA

RTC

40 60 1st COMPACT (IC)

2nd COMPACT (TC)

48Ca (5.47 MeV/u) + 243Am (0.8 mg/cm2)

4 events expected in 20 days irradiation if Nh is volatile similar to Cn and Fl GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 12 Experimental conditions

° 48Ca (5.47 MeV/u) + 243Am (0.8 mg/cm2) ° Experiment duration 20 days ° Beam integral 4.4E18 ° RTC covered with Teflon 24 cm3 ° Gas flow (He:Ar=1:1) 2 L/min ° RTC – COMPACT1 cappilary 5 (10) cm long st ° 1 COMPACT – IC at room temperature SiO2 Au

° 2nd COMPACT – TC (-10 °C...... -165 °C) Au

GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 13 Flush out time measurements

150 Time Distribution in COMPACT 1 Hg decay in flight

100 Counts 50 Background from 219Rn decay

0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Time / s

GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 14 Results

° Chemical yield (measured for 182Hg) ~60% (prelim.) ° Flush out time (measured for 182Hg) ~100% within 1 s ° Nh transmission in TASCA with reduced field in Q2 20 to 30%

° 4 (3) events from 288Nh were expected at the overall efficiency from Fl experiment (with reduced field in Q2) ° No α(n) –SF decaychainswereobserved ° Non-observation of Nh in COMPACT points at a stronger reactivity of Nh compared to Fl, as expected

° Two coincident SF events without α precursor ° Most probable origin of SF events is from Cn or Fl →→→ ° This points at a possible EC decay in Nh or Mc (E115)

GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 15 Summary and outlook

° First experiments on Nh chemistry performed at GSI ° Goal: gas chromatography of Nh on quartz and gold ° Despite 3-4 events were expected, no one was observed

Preliminary conclusions: ° Nh is more reactive than Fl ° SF events, probably from Cn/Fl, point at a possible EC branch in Nh/Mc

° For conclusive experiment more beam time is needed – direct measurement of Nh in FPD and in COMPACT

GSI Helmholtzzentrum für Schwerionenforschung GmbH 29.08.2016 16