Decay spectroscopy of neutron-rich isotopes for astrophysics at GSI, IGISOL, TRIUMF, and RIKEN

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1 Canada s national laboratory for particle and nuclear physics Laboratoire national canadien pour la recherche en physique nucléaire et en physique des particules Decay spectroscopy of neutron-rich isotopes for astrophysics at GSI, IGISOL, TRIUMF, and RIKEN Iris Dillmann Associate Scientist, TRIUMF Adjunct Professor, University of Victoria Accelerating Science for Canada Un accélérateur de la démarche scientifique canadienne Owned and operated as a joint venture by a consortium of Canadian universities via a contribution through the National Research Council Canada Propriété d un consortium d universités canadiennes, géré en co-entreprise à partir d une contribution administrée par le Conseil national de recherches Canada

2 Nuclear Physics Input Masses: define reaction path Half-lives: define shape Shell structure far off stabilty: defines position of abundance peaks Neutrons from b-delayed neutron emission or (g,n): smoothing of abundance curve Need experimental information for isotopes between reaction path and stability! June 7th, 2016 Iris Dillmann - JINA r-process workshop 2

3 Go East: Exploring the Terra Incognita bn-emission will become dominant process b-delayed 2-/ 3-neutron emitters June 7th, 2016 Iris Dillmann - JINA r-process workshop 3

4 b-delayed neutron (bn) emission Catch me if you can! S n < Q b Delayed : emission with b-decay half-life of the precursor A Z (t 1/2 = ms...90 s) n branching ratio (P 1n -value) Q b S n June 7th, 2016 Iris Dillmann - JINA r-process workshop 4

5 Canadian evaluation efforts Coordinated Research Project ( ) Evaluation of Z=29-84 underway (publication in 2017) June 7th, 2016 Iris Dillmann - JINA r-process workshop 5

6 BELEN-30 at GSI Darmstadt/ Germany June 7th, 2016 Iris Dillmann - JINA r-process workshop 6

7 BEta delayed Neutron detector (BELEN) Universidad Politecnica de Cataluna, Barcelona IFIC Valencia CIEMAT Madrid GSI Helmholtz Center Darmstadt High-pressure 3 He long counters in polyethylene moderator: 3 He + n 3 H + p kev June 7th, 2016 Iris Dillmann - JINA r-process workshop 7

8 GSI Darmstadt (2011) 70 m 1 GeV/ u 238 U pps Be target Target Fragment Separator 1 m n n S4 focal area Implantation detector SIMBA Neutron-rich 238 U fragments n Shielding (PE + borated rubber) n Neutron detector BELEN-30 (e n 40%) June 7th, 2016 Iris Dillmann - JINA r-process workshop 8

9 GSI Darmstadt (2011) PhD R. Caballero (UPC Barcelona) Au, Hg, Tl, Pb, Bi PhD K.I. Smith (U Notre Dame) Ag Pd June 7th, 2016 Iris Dillmann - JINA r-process workshop 9

10 South/ east of 208 Pb R. Caballero-Folch et al., accepted by PRL (2016) 9 first t 1/2 measurements 8 first P 1n -value measurements Roger Caballero-Folch (UPC Barcelona, now at TRIUMF) June 7th, 2016 Iris Dillmann - JINA r-process workshop 10

11 P 1n results R. Caballero-Folch et al., accepted by Phys. Rev. Lett. (2016) First cases for benchmarking of theoretical models in this mass region New RHB+RQRPA (Marketin et al. 2015) doing better than FRDM+QRPA (Moeller et al. 2003) June 7th, 2016 Iris Dillmann - JINA r-process workshop 11

12 t 1/2 results R. Caballero-Folch et al., accepted by Phys. Rev. Lett. (2016) Different agreement before and behind shell closure: - New RHB+RQRPA (2015) better for N<126 proton-neutron relativistic quasiparticle phase approx. based on the Hartree-Bogoliubov model - FRDM+QRPA (2003) better for N>126 June 7th, 2016 Iris Dillmann - JINA r-process workshop 12

13 t 1/2 results: N<126 (south-west of 208 Pb) FRDM+QRPA: well-known to underpredict N<126 t 1/2 by factor of 20 Reason: increasing contribution of FF transitions towards higher Z-values. Gamow-Teller (GT) transitions get progressively Pauli blocked by the filling of the h11/2 proton orbital, which reduces contributions from allowed nh9/2- ph11/2 transitions RHB-RQRPA better (only factor 3 discrepancy) R. Caballero-Folch et al., accepted by Phys. Rev. Lett. (2016) June 7th, 2016 Iris Dillmann - JINA r-process workshop 13

14 t 1/2 results: N>126 (south-east of 208 Pb) FRDM+QRPA: good agreement with experiments Reason: indication of the predominance of allowed ni11/2 pi13/2 GT-transitions south-east" of 208 Pb. RHB+RQRPA worse: factor 60 lower Reason: This feature may be ascribed to a specific neutronexcess dependent ansatz for the strength of the T=0 protonneutron (dynamic) pairing assumed. This free parameter has a strong in influence on the beta-decay strength function This parameter was fitted to the available decay rates, which did not include the isotopes with very high (N-Z) values studied in the present work. R. Caballero-Folch et al., accepted by Phys. Rev. Lett. (2016) June 7th, 2016 Iris Dillmann - JINA r-process workshop 14

15 BELEN is a beamigrant BELEN-48 at IGISOL/Finland (2014) UPC Barcelona: R. Caballero-Folch, F. Calvino, G. Cortès, A. Riego, P. Salvador-Castiñeira IFIC Valencia: J. Agramunt, J.L. Tain, A. Algora, V. Guadilla, A. Montaner-Pizá, S. Orrigo, B. Rubio TRIUMF Vancouver: I. Dillmann GSI Darmstadt: M. Marta CIEMAT Madrid: E. Mendoza U of Surrey: B. Gelletly U of Brighton: Ch. Nobs U of Istanbul: E. Ganioglu U of Helsinki: J. Äysto U of Jyvaskyla: L. Canete, T. Eronen, D. Gorelov, J.Hakala, A. Jokinen, A. Kankainen, V. Kolhinen, J. Koponen, I. Moore, H. Penttilä, I. Pohjalainen, J. Reinikainen, S. Rinta-Antila, V. Simutkin, A. Voss June 7th, 2016 Iris Dillmann - JINA r-process workshop 15

16 BELEN-48 GSI experiments: e 1n (BELEN-30)= 40% IGISOL experiments: Matrix 1: e 1n (BELEN-48)= 40% Matrix 2: e 1n (BELEN-48)= 60% e 2n (BELEN-48)= 36% June 7th, 2016 Iris Dillmann - JINA r-process workshop 16

17 Experimental program IAEA top priority list for remeasurement of P 1n values for reactor physics: I. Dillmann et al., IAEA(NDS)-0643 (2014) 2 weeks beamtime: measured 12 isotopes with high accuracy: 1 week: 95 Rb, 98,98m Y, 99 Y 136,138 Te, 135,137 Sb, 137,138,139,140 I 1 week 136 Sb I have measured 136 Sb, the heaviest b2n emitter so far! June 7th, 2016 Iris Dillmann - JINA r-process workshop 17

18 Multiple-neutron emitter beyond N= Sb: P 1n = 16.3 (32)% P 2n (pred)= 6.2% June 7th, 2016 Iris Dillmann - JINA r-process workshop 18

19 Heaviest b2n-emitter identified! Heaviest b2n-emitter so far: 98,100 Rb 136 Sb: ALTO meas. not conclusive (isobaric cont.): P 2n 1.4% IGISOL: purification in JYFLTRAP, no isobars 128h beamtime, ca bnn-events expected Preliminary result: 27 events P 2n ~0.2% June 7th, 2016 Iris Dillmann - JINA r-process workshop 19

20 The future of bn-measurements The BRIKEN project (2016/17) Beta-delayed neutron measurements at RIKEN for nuclear structure, astrophysics, and applications June 7th, 2016 Iris Dillmann - JINA r-process workshop 20

21 New BRIKEN Hybrid detector Clover Imp Clover He counters from Germany, Japan, Russia, Spain, USA 2 clovers (USA) Implantation detector AIDA (UK) Setup: July 2016 Commissioning: Sept Beamtime: >Nov e(1n)= 69% e(2n) 50% June 7th, 2016 Iris Dillmann - JINA r-process workshop 21

22 BRIKEN: Proposed program 3 Proposals accepted: 76 Co- 92 Se (ca. 30 isotopes) 121 Rh- 152 Ba (ca. 33 isotopes) 93 Se- 121 Tc: 90 new P 1n 20 new P 2n 23 new half-lives June 7th, 2016 Iris Dillmann - JINA r-process workshop 22

23 Half-life measurements of neutron-rich Cd isotopes June 7th, 2016 Iris Dillmann - JINA r-process workshop 23

24 Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei GRIFFIN High efficiency g-ray spectrometer (replaced 8p spectrometer) 16 HPGe Clovers (e= 17% at 1 MeV) Coupled with ancillary detectors: plastic scintillators, conversion electron spectrometer, LaBr 3 fast timing array, neutron detectors,... Lowest beam yield ever measured at TRIUMF: 0.15 pps for 132 Cd Commissioning in September 2014 First physics experiments 2014: 115g,m Ag; 32 Na; 46 K, 47 K Physics experiments 2015: 32 Na; Mg; Cd; 62 Ga; 26 Na... June 7th, 2016 Iris Dillmann - JINA r-process workshop 24

25 First GRIFFIN physics paper published! Measurements done in August 2015 Data analyzed by PhD student Ryan Dunlop (Guelph) accepted by PRC Rapid Comm. June 7th, 2016 Iris Dillmann - JINA r-process workshop 25

26 Results: 128,129 Cd Previous measurements 128 Cd: 280(40) ms 129 Cd (3/2 + ): 242(8) ms 129 Cd(11/2 - ): 104(6) ms B. Fogelberg et al., Proc. Int. Conf. Nucl. Data for Sci. and Techn., p. 837 (1988). O. Arndt et al., Acta Phys. Pol.B 40, 437 (2009). EURICA (2015) 245(5) ms 146(8) ms 155(3) ms G. Lorusso et al., PRL 114, (2015). GRIFFIN 246.2(21) ms 157(8) ms 147(3) ms June 7th, 2016 Iris Dillmann - JINA r-process workshop 26 R. Dunlop et al., accepted by Phys. Rev. C. Rapid Comm. (2016)

27 130 Cd controversy (N=82) 130 Cd half-life: ISOLDE (1986): ISOLDE (2001): EURICA (2015): GRIFFIN (2016): t 1/2 = 195(35) ms t 1/2 = 162(7) ms t 1/2 = 127(2) ms t 1/2 = 126(4) ms R. Dunlop et al., accepted by Phys. Rev. C. Rapid Comm. (2016) K.-L. Kratz, et al., Z. Phys. A 325, 489 (1986). M. Hannawald et al., NP A688, 578 (2001). G. Lorusso et al., PRL 114, (2015). Previous 130 Cd half-life was used to adjust Gamow-Teller quenching factor for lighter N=82 isotopes New predictions will yield shorter half-lives for 128 Pd, 127 Rh, 126 Ru when adjusted to new quenching factor June 7th, 2016 Iris Dillmann - JINA r-process workshop 27

28 Next step: GRIFFIN + DESCANT DESCANT DEuterated SCintillator Array for Neutron Tagging Commissioned in 2013 with TIGRESS, in 2016 with GRIFFIN 70 deuterated scintillators Measurement of bn-emitters for nuclear structure and astrophysics studies 2 accepted proposals, more to follow after commissioning in summer June 7th, 2016 Iris Dillmann - JINA r-process workshop 28

29 Outlook Recent revival (boost) of bn-program - Present focus on isotopes around N= Access to N=126: up to now only at GSI (-> FAIR, FRIB) Huge program for measurements of neutron-rich key-isotopes planned in next few years (half-lives, b-delayed neutron emission probabilities, nuclear structure) Extrapolation to r-process regions require reliable theoretical models June 7th, 2016 Iris Dillmann - JINA r-process workshop 29

30 The new ARIEL facility New proton spallation beamline on UC x r-process region Photo-fission on UC x target r-process region March 29th, 2016 Iris Dillmann JINA-CEE meeting 30

31 Photofission: Calculated in-target yields Courtesy of A. Gottberg (TRIUMF) June 7th, 2016 Iris Dillmann - JINA r-process workshop 31

32 Some elements cannot be extracted planning/yield/beam June 7th, 2016 Iris Dillmann - JINA r-process workshop 32

33 Don t forget: We are an ISOL facility! Extraction yields depend on chemistry! p spallation Courtesy of A. Gottberg and P. Kunz (TRIUMF) June 7th, 2016 Iris Dillmann - JINA r-process workshop 33

34 a) Cleaner beams, more neutron rich (CANREB + photofission) b) New beamline (BL4N) will allow parallel operation How do we profit from ARIEL? c) e-linac can run when cyclotron is shut-down d) Enhanced beam development opportunities on both beamlines March 29th, 2016 Iris Dillmann JINA-CEE meeting 34

35 Canada s national laboratory for particle and nuclear physics Laboratoire national canadien pour la recherche en physique nucléaire et en physique des particules Thank you! TRIUMF: Alberta British Columbia Calgary Carleton Guelph Manitoba McGill McMaster Montréal Northern British Columbia Queen s Regina Saint Mary s Simon Fraser Toronto Victoria Western Winnipeg York Merci! Questions? Owned and operated as a joint venture by a consortium of Canadian universities via a contribution through the National Research Council Canada Propriété d un consortium d universités canadiennes, géré en co-entreprise à partir d une contribution administrée par le Conseil national de recherches Canada