Aberg, S.

Ackermann, D.

Andersson, L.-L.

Block, M.

Brand, H.

Carlsson, B. G.

Cox, D.

Derkx, X.

Di Nitto, A.

Düllmann, C. E.

Eberhardt, K.

Even, J.

Fahlander, C.

Forsberg, U.

Gates, J. M.

Gerl, J.

Golubev, P.

Gregorich, K. E.

Gross, C. J.

Herzberg, R.-D.

Heßberger, F.

Jäger, E.

Khuyagbaatar, J.

Kindler, B.

Kojouharov, I.

Kratz, J. V.

Krier, J.

Kurz, N.

Lommel, B.

Mistry, A.

Mokry, C.

Nitsche, H.

Omtvedt, J. P.

Papadakis, P.

Ragnarsson, I.

Rudolph, D.

Runke, J.

Rykaczewski, K.

Sarmiento, L. G.

Schaffner, H.

Schausten, B.

Schädel, M.

Thörle-Pospiech, P.

Torres, T.

Traut, T.

Trautmann, N.

Türler, A.

Ward, A.

Ward, D. E.

Wiehl, N.

Yakushev, A.

Rudolph, Dirk

Forsberg, Ulrika

Golubev, Pavel

Sarmiento, Luis

Åberg, Sven

Carlsson, Gillis

Fahlander, Claes

Ragnarsson, Ingemar

Ward, Daniel

Lund University Publications

Element 115 Studied with TASISpec

GSI Repository

Element 115 studied with TASISpecD. Rudolph1, U. Forsberg1, P. Golubev1, L.G. Sarmiento1, A. Yakushev2, L.-L. Andersson3, A. DiNitto4, Ch.E. Du¨llmann2,3,4, J.M. Gates5, K.E. Gregorich5, C.J. Gross6, R.-D. Herzberg7,F.P. Heßberger2,3, J. Khuyagbaatar3, J.V. Kratz4, K. Rykaczewski6, M. Scha¨del2,8, S. ◦Aberg1,D. Ackermann2, M. Block2, H. Brand2, B.G. Carlsson1, D. Cox7, X. Derkx3,4, K. Eberhardt3,4,J. Even3, C. Fahlander1, J. Gerl2, E. Ja¨ger2, B. Kindler2, J. Krier2, I. Kojouharov2, N. Kurz2,B. Lommel2, A. Mistry7, C. Mokry3,4, H. Nitsche5, J.P. Omtvedt9, P. Papadakis7, I. Ragnarsson1,J. Runke2, H. Schaffner2, B. Schausten2, P. Tho¨rle-Pospiech3,4, T. Torres2, T. Traut4, N. Trautmann4,A. Tu¨rler10, A. Ward7, D.E. Ward1, and N. Wiehl3,41Lund University, Lund, Sweden; 2GSI Helmholtzzentrum fu¨r Schwerionenforschung GmbH, Darmstadt, Germany;3Helmholtz Institute Mainz, Mainz, Germany; 4Johannes Gutenberg-Universita¨t Mainz, Mainz, Germany; 5LawrenceBerkeley National Laboratory, Berkeley, USA; 6Oak Ridge National Laboratory, Oak Ridge, USA; 7University ofLiverpool, Liverpool, United Kingdom; 8Advanced Science Research Center, Japan Atomic Energy Agency, Tokai,Japan; 9University of Oslo, Oslo, Norway; 10Paul Scherrer Institute and University of Bern, Villigen, SwitzerlandAn experiment was conducted at GSI to fingerprint theproton number of one or several isotopes along antici-pated decay chains of element 115 by means of high-resolution coincidence spectroscopy of α decays and pho-tons. The fusion-evaporation reaction 48Ca+243Am [1] wasused. The residues were separated from primary beam andbackground by TASCA [2-4] and guided into the TASISpecset-up [cf. Fig. 1(a)] [5, 6].(b)ClusterClover6 cm(a)4.8(   ) s 8 6α 9.77Rg 280γ 194,23713 9α 9.53,9.60γ 362,434,...Mt 2760.70(    ) s115−288α0.16(  ) s2310.3−10.6113−284α12160.92(    ) s9.9−10.225(   ) h43Db 268sf1.4(    ) h18 5α 9.28(6)43 7α 9.07,8.93199 3482(      ) ms223 3851 chainsα115−28742(    ) ms5715sfDb 2671.8(    ) sBh 271γ   (~140)Bh 2721510.9(    ) s21α10.61(4)10.23(1)113−283Rg 27993(      ) msα 10.38(11)3 chainsMt 2752821(    ) ms 8α 10.33(1)Figure 1: (a) Photograph of the TASISpec α-photon coinci-dence set-up [5] in the focal plane of the TASCA gas-filledseparator at GSI [2]. See text for details. (b) Proposed de-cay chains of 287,288115 based on the combined data andassignments of Refs. [7-9].22 and 1 correlated decay chains were found to be con-sistent with 31 and 2 previously reported chains associatedwith 288115 and 287115, respectively [cf. Fig. 1(b)] [7, 8].16 prompt α-photon coincidences were recorded along the288115 chain [9-11]. Seven short chains of types recoil-α-(α)-fission deserve specific attention [12].The conclusion of Ref. [9] notes that “thirty corre-lated α-decay chains were observed following the reac-tion 48Ca+243Am. Decay schemes arising from high-resolution spectroscopic coincidence data, in conjunctionwith comprehensive Monte-Carlo simulations, open thedoor for direct nuclear structure insights of these heavi-est man-made atomic nuclei. Previous assignments linkingthe majority of the decay chains to the decay of 287,288115[7, 8] are confirmed. This includes first candidates for Z-fingerprinting the decay of Mt by means of characteristicK-X ray detection. There is clearly potential for directdetermination of the atomic number of the descendants ofsuperheavy elements.”Following press releases the topic received significantmedia attention [13], not least due to precisely element 115starring in various computer games – and Area 51 [14].The authors thank the ion-source and accelerator staff atGSI. This work is supported by the European CommunityFP7 – Capacities ENSAR No. 262010, the Royal Physio-graphic Society in Lund, the Euroball Owners Committee,the Swedish Research Council, the German BMBF, the Of-fice of Nuclear Physics, U.S. Department of Energy, andthe UK Science and Technology Facilities Council.References[1] 243Am material provided by ORNL and targets made at JGU.[2] M. Scha¨del, Eur. Phys. J. D 45, 67 (2007).[3] J.M. Gates et al., Phys. Rev. C 83, 054618 (2011).[4] U. Forsberg et al., Acta Phys. Pol. B43, 305 (2012).[5] L.-L. Andersson et al., Nucl. Instr. Meth. A622, 164 (2010).[6] L.G. Sarmiento et al., Nucl. Instr. Meth. A667, 26 (2012).[7] Yu. Ts. Oganessian et al., Phys. Rev. C 69, 021601(R) (2004).[8] Yu. Ts. Oganessian et al., Phys. Rev. C 87, 014302 (2013).[9] D. Rudolph et al., Phys. Rev. Lett. 111, 112502 (2013).[10] U. Forsberg et al., Proceedings INPC 2013, Florence, Italy,EPJ Web of Conferences, in press.[11] D. Rudolph et al., Acta Phys. Pol. B, in press.[12] U. Forsberg et al., to be published.[13] http://www.fysik.lu.se/om institutionen/nyheter/nyheter 2013/element-115-news-feed/ (selection of news articles).[14] http://www.youtube.com/watch?v=mpmAXO2-gSohttp://www.youtube.com/watch?v=BJYDrugEtxYhttp://www.youtube.com/watch?v=q0lSL1yD5qQhttp://www.youtube.com/watch?v=YW4zzo3F2acNUSTAR-SHE-02 GSI SCIENTIFIC REPORT 2013126 doi:10.15120/GR-2014-1-NUSTAR-SHE-02

Element 115 studied with TASISpec

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Element 115 studied with TASISpec

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