PHYSICAL PROBLEMS TO BE CLARIFIED WITH THE USE OF RADIOACTIVE ION BEAMS OF THE ACCULINNA-2 SEPARATOR

PHYSICAL PROBLEMS TO BE CLARIFIED WITH THE USE OF RADIOACTIVE ION BEAMS OF THE ACCULINNA-2 SEPARATOR Grzegorz Kamiński for the ACCULINNA group FLNR, JINR, DUBNA International Nuclear Physics Conference (INPC2016) Adelaide Convention Centre, Australia September 11-16, 2016 A.S. Fomichev talk

Short outline Introduction: Light RIB facility at FLNR: ACCULINNA & ACCULINNA-2 Experiments & Physical problems to be clarified 2

Superheavy and superlight research at FLNR, JINR Elements 102-108 synthesized at FLNR Elements: (IUPAC approval) 113 Nihonium (2016) 114 Flerovium (2011) 115 Moscovium (2016) 116 Livermorium (2011) 117 Tennessine (2016) 118 Oganesson (2016) Last two decades: Elements 113-118 synthesized at FLNR Superheavy 3

Superheavy and superlight research at FLNR, JINR Elements 102-108 synthesized at FLNR Elements: (IUPAC approval) 113 Nihonium (2016) 114 Flerovium (2011) 115 Moscovium (2016) 116 Livermorium (2011) 117 Tennessine (2016) 118 Oganesson (2016) Last two decades: Elements 113-118 synthesized at FLNR Superheavy ACCULINNA&ACCULINNA-2 Recent achievements Current developments Future proepscts Light & Superlihght 4

Layout of ACCULINNA-2 More details about ACCULINNA -2 G. Kaminski talk, Friday L3 : 11:40 5

Layout of ACCULINNA-2 6

Energy MeV/nucleon Beams and energies @ ACCULINNA-2 somewhere among other facilities Atomic number 7

RIBs from ACCULINNA-2 Primary beam Radioactive Ion Beam Ion Energy, MeV/u Ion Energy, MeV/u Intensity, s 1 (per 1 pµa) Purity, % 11 B 32 8 He 26 3*10 5 90 15 N 49 11 Li 37 3*10 4 95 11 B 32 10 Be 26 1*10 8 90 15 N 49 12 Be 38.5 2*10 6 70 18 O 48 14 Be 35 2*10 4 50 22 Ne 44 calculations done with LISE++ 17 C 33 3*10 5 40 18 C 35 4*10 4 30 36 S 64 24 O 40 2*10 2 (U400M upgrade) 10 B 39 7 Be 26 8*10 7 20 Ne 53 18 Ne 34 2*10 7 32 S 52 28 Be 31 2*10 4 10 (with RF kicker) 90 40 5 (with RF kicker)

Z Activity of ACCULINNA 27 S ACC 9 He 10 He 4 H 9

Z Scope of activity for ACCULINNA-2 27 S 4 H 9 He 10 He ACC ACC2 - first experiments ACC2 - further studies 10

ACCULINNA-2 - reactions Pole mechanism inherent to the direct reactions 13 B (- 3p) 10 Be 12 Be 14 Be Reactions leading to the formation of heavy helium isotopes 9 Li (- d) 11 Li (- 2p) (- p) (- α) 8 He 10 He 9 He (d,p) (t,p) 11

ACCULINNA-2 - reactions Pole mechanism inherent to the direct reactions 13 B (- 3p) 10 Be 12 Be 14 Be Reactions leading to the formation of heavy helium isotopes 9 Li (t, 3 He) (- d) (d,α) 11 Li 8 He 10 He 9 He (- 2p) (d, 3 He) (- p) (- α) (d, 6 Li) (d,p) (t,p) 12

5 H studied by means of the 3 H(t,p) 5 H reaction Spectrum deuced from the correlation analysis Experimental setup 5 H experimental spectrum Cryogenic tritium target cell A.A. Korsheninnikov, 2001, Discovery of 5 H at FLNR 6 He(p,2p) 5 H M.S. Golovkov, 2004, Pioneering correlation studies A.A. Korsheninnikov et al., PRL 87 (2001) 92501. M.S.Golovkov et al., PLB 566 (2003) 70. M.S.Golovkov et al., PRL 93 (2004) 262501. S.V. Stepantsov et al., NPA 738 (2004) 436. M.S.Golovkov et al., PRC 72 (2005) 064612. Poor population of ground state. However, correlations provide enough selectivity: quantum amplification 5 H ground state position is finally established; the excited state is established as 3/2 + -5/2 + degenerate mixture Spin-parity identification made by the correlation analysis of direct reaction products

Challenge issued by the 9 He 10 He couple 9 He, 10 He - published papers: 9 He 10 He K. K. Seth et al., Phys. Rev. Lett. 58, 1930 (1987). H. G. Bohlen et al., Z. Phys. A 330, 227 (1988). W. von Oertzen, Nucl. Phys. A 588, c129 (1995). L. Chen et al., Phys. Lett. B 505 (2001) 21 26 M. S. Golovkov et al., Phys. Rev. C 76, 021605(R) (2007). S. Fortier et al., AIP Conf. Proc. 912, 3 (2007). H.T. Johansson et al., Nucl. Phys. A 842, 15 (2010). H Al Falou et al., J. Phys. Conf. Se. 312, 092012 (2011). T. Al Kalanee et al., Phys. Rev. C 88, 034301 (2013). E.Uberseder et al., Phys. Lett. B 754, 323 (2016). S. I. Sidorchuk et al., Phys. Rev. Lett. 108, 202502 (2012). Z. Kohley et al., Phys. Rev. Lett. 109, 232501 (2012). H.T. Johansson et al., Nucl. Phys. A 842, 15 (2010). M. D. Jones, et al., Phys. Rev. C 91, 044312 (2015). A. Matta et al., Phys. Rev. C 92, 041302(R) (2015). 14

9 He P. G. Sharov, I. A. Egorova, and L. V. Grigorenko, C90, 024610 (2014). Limits on the s-wave 1/2 + and p-wave 1/2 interactions in 9 He ( 8 He + n channel). We can see that practically none of the available experimental data are consistent with these constrains. Its evident that full conclusive experimental studies of 9 He with convincing statistics, sufficient energy resolution, and clear spin parity identification of the states are required 15

ACCULINNA-2: 9 He 9 He: the problem of unambiguous spectrum identification 80 M. S. Golovkov, et al., Phys. Rev. C 76 021605 (2007) 60 Complete kinematic data and correlation analysis. Counts / 333 kev 40 20 0 1/2 5/2 1/2 + 0 2 4 6 E 9He, MeV 8 Counts/(12 o ) 6 4 2 0

ACCULINNA-2 9 He from the 8 He( 2 H,p) 9 He reaction ACCULINNA ACCULINNA-2 Missing mass Counts 900 10 5 Resolution 800 kev 300 kev θ 8He 12 o 0.3 o Combined mass Counts 3 x 10 4 Resolution - 100 kev A setup for the 9 He and 10 He study at ACCULINNA-2 Zero degree spectrometer

Structure of 10 He Low-Lying States S. I. Sidorchuk et al., Phys. Rev. Lett. 108, 201502 (2012) 18

Structure of 10 He Low-Lying States 0 + 1 2 + states not included in analysis L.V. Grigorenko and M.V. Zhukov, Phys. Rev. C 77, 034611 (2008). 19

10 He: prospects assumed for ACCULINNA-2 10 He from 8 He( 3 H,p) 10 He Other reactions ACCULINNA ACCULINNA-2 Missing mass spectrum Count number in 0 + state ~120 2 x 10 4 Resolution 500 kev 200 kev Resolution in θ 8He 12 o 0.3 o Correlation analysis for the tripple (p- 8 He-n) events Counts (E T = 0 10 MeV) 3 x 10 5 11 Li( 2 H, 3 He) 10 He 14 Be( 2 H, 6 Li) 10 He Missing mass spectrum Counts in 0 + state 2 x 10 3 3 x 10 3 Resolution 400 kev 200 kev 20

7 H M.S. Golovkov et al., Phys. Lett. B 588, 163 (2004) Limit T 1/2 < 1 ns was set for the 7 H lifetime, which allowed the authors to estimate a lower limit of 50 100 kev for the 7 H energy above the 3 H + 4n breakup threshold. L. V. Grigorenko et al., Phys. Rev. C 84, 021303(R) (2011). T 1/2, s Г, MeV E T, MeV 21

7 H M. Caamaño, et al., Phys. Rev. C 78, 044001 (2008) 7 H resonance was observed 0.57 ± 0.42/0.21 MeV above the 3 H + 4n threshold with a width of 0.09 ± 0.94/0.06 MeV. 8 He @ 15.4 AMeV + 12 C target E t+4n, MeV counts A.A. Korsheninnikov et al., Phys. Rev. Lett. 90 082501 (2003); 8 He( 1 H,2p) 7 H E.Yu Nikolskii et al., Phys. Rev. C 81, 064606 (2010). 2 H( 8 He, 3 He) 7 H 22

7 H: prospects assumed for ACCULINNA-2 7 H: experiments to be done at ACCULINNA-2 8 He( 2 H, 3 He) 7 H 11 Li( 2 H, 6 Li) 7 H Missing mass spectrum Counts in 0 + state 2 x 10 2 dσ/dω 10 µb/sr 3 x 10 3 dσ/dω 10 µb/sr Resolution 400 kev 200 kev Exciting option is to try the 8 He + 3 H reaction. The 4n transfer can be searched for down to a limit of dσ/dω 10 nb/sr. The 2n transfer and triton transfer channels, as well as elastic scattering, will be accessible for study. 23

17 Ne Nuclear structure Nuclear astrophysics 17 Ne is 2p-halo candidate 17 Ne is only one known nuclear system, which excited state can decay through direct 2p emission. 2p radiative capture is a possible by-pass of the 15 O waiting point in the astrophysical rp-process The two-proton decay energy of the 17 Ne 3/2 state (E*=1288keV) makes 344 kev and the one-proton decay is energetically prohibited for this state. Hence, this is a candidate for a true two-proton emitter, and the 2p decay branch can compete with the γ decay to the 17 Ne ground state. The 2p-decay width of the 17 Ne 3/2 state is of interest for the theory analyzing the dynamics of the true 2p decay. The daughter 15 O nucleus is a waiting point in the CNO cycle of nucleosynthesis in a hot and dense stellar substance. The reaction 15 O(2p,g) 17 Ne could be a bypass [Goerres J, Wiescher M, Thielemann F-K Phys. Rev. C 51 392 (1995)]. Theory estimate makes necessary the search for the partial width going down to Γ 2p ~ (5-8)*10 15 MeV, i.e. to a branching ratio Γ 2p / Γ γ ~ (2-3) 10-6,L. V. Grigorenko and M. V. Zhukov, Phys. Rev. C 76, 014008 (2007) 24

Combined mass approach: 18 Ne(p,d) 17 Ne Combined mass approach to the study of decay modes of exotic nuclei. The emission angle of the recoil deuteron is defined with error making ±1. In that case the emission angle and energy of 17 Ne become ascertained with accuracy: Δθlab» 0.1 ΔE/Elab» 0.0025. Using rather thick targets one can rely on a ~200-keV resolution obtained for the measured decay energy of the nucleus being under study ( 17 Ne). 25

17 Ne: 18 Ne(p,d) 17 Ne Combined mass spectrum of 17 Ne measured by the Acculinna provided a limit Γ 2p / Γ γ < 8 * 10 5 [ P. Sharov et al., talk given at EXON2016 ]. Our task is to come to a level of Γ 2p / Γ γ ~ (2-3) * 10 6 in a priority experiment which will be carried out at ACCULINNA-2. Beam 18 Ne Target liquid hydrogen aluminum shield proton telescope The VIII International Symposium on EXOtic Nuclei (EXON-2016), 4-10 September 2016, Kazan, Russia 26

β - delayed particle emission from 27 S β - delayed particle emission from 27 S New decay channels possible Already known decay branches G. Canchel et al., Eur. Phys. J. A 12, 377 (2001). 27

β - delayed particle emission from 27 S β - delayed particle emission from 27 S New decay channels possible Specific equipment development: Warsaw Optical Time Projection Chamber (OTPC) Already known decay branches G. Canchel et al., Eur. Phys. J. A 12, 377 (2001). K. Miernik et al., NIM A581 (2007) 194 Example studies with OTPC 28

β - delayed particle emission from 27 S Analysis in progress p p 27 27 S S 27 S p p p 27 S L. Janiak, UW, Warsaw In 2017 a new measurment of β - delayed particle emission from 27 S @ ACCULINNA-2 is planned buch better statistic two orders of magnitude 29

THANK YOU FOR ATTENTION! 30