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PJ Woods University of Edinburgh

A personal view of the shape of things to come in Explosive Nuclear Astrophysics. PJ Woods University of Edinburgh. Elemental abundances in novae ejecta. 1.35 M Sun ONe nova. J. José, M. Hernanz, C. Iliadis. Nucl Phys A , 777 , (2006), 550-578.

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PJ Woods University of Edinburgh

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  1. A personal view of the shape of things to come in Explosive Nuclear Astrophysics PJ Woods University of Edinburgh

  2. Elemental abundances in novae ejecta 1.35 MSun ONe nova J. José, M. Hernanz, C. Iliadis. Nucl Phys A, 777, (2006), 550-578

  3. Presolar grains • Grains of nova origin are thought to have a large 30Si/28Si ratio. • Abundance of 30Si is determined by the competition between the 30P β+ decay and the 30P(p,γ)31S reaction rate. Andrew M Davis. University of Chicago

  4. Novae Nucleosynthesis 31Cl 32Cl 33Cl 34Cl (p,γ) β+ (γ,p) 30S 31S 32S 33S 28P 27P 29P 31P 30P 2.498m 28Si 29Si 26Si 27Si 30Si

  5. 30P(p,γ)31S reaction rate using new resonance data However, key resonance strengths, ωγ , based on systematic values for proton spectroscopic factors

  6. use transfer reactions to estimate Гp for (p,γ) reactions where resonance has Гp<< Гγ , ωγis proportional toГp. Гp α Pl (barrier penetration factor) X S(spectroscopic factor) σtransfer = σDWBA X S

  7. New technique for (d,n) studies of (p,γ) resonance strengths with GRETINA γ-array and S800 spectrometer PJW, H Schatz et al., NSCL, April 2013 ~106 30P 30 MeV/u ions on CD2 target Measure σ(d,n)INT Гp for strong resonances

  8. 31S gamma spectrum CD2 CH2 5143 keV 6327 keV Analysis - A Kankainen

  9. Astrophysically relevant levels in 31S 6833 T=0.6 GK 6636 6583 6542 T=0.4 GK 6394 6393 6377 5/2+ T=0.2 GK 6357 3/2- 6327 T=0.1 GK 6283 6259 6159 1+ 6138 Sp=6130.9(4) keV 30P + p 31S Reaction calculations of Γp from data being performed by F Nunes

  10. Galactic abundance distribution of the cosmic γ-ray emitter 26Al INTEGRAL satellite telescope - 2.8(8) Msun of 26Al in our galaxy [R. Diehl, Nature 439 45(2006)]

  11. Mg-Al Cycle Hydrogen burning in Mg – Al Cycle 26 27 28 Si Si Si 25 26 27 Al Al Al 6s 1Myr 24 25 26 Mg Mg Mg 1.809 MeV

  12. MD1 ED1 Direct measurement of 26gAl(p,γ)27Si reaction on 188 keV resonance, PRL 96 252501(2006)  lower energy resonances may play dominant role for destruction of 26Al burning in W-R stars?

  13. High resolution d(26gAl,p)27Al study of analog states of 27Si resonances using Edinburgh TUDA Si array @ Triumf proton 150 MeV 26gAl  (CD2)n target Ibeam~ 5*108 pps 0  increasing excitation energy Astrophysically Important Region

  14. Key analog states 8043 9/2− 7175 9/2+ 7292 13/2+ 7997 9/2+ 7948 11/2+ 7806 9/2+ 7402 11/2+ 7444 13/2+ 7664 9/2+ 8097 5/2+ Exotic reaction since Jπ= 5+ for 26gAl!

  15. Future 26mAI(3He,d)27Si study on TSR storage ring@ISOLDE • isomer can be excited in • core collapse supernovae • influences ‘extinct’ 26Al • observed in meteorites as • excess 26Mg In-ring target chamber & heavy-ion recoil detection system in UHV

  16. In-ring DSSD System for ultra-high resolution (d,p), (p,d) and (3He,d) transfer studies of astrophysical resonancesISOL-SRS project For ultra high resolution mode resolution should be entirely limited by transverse beam emittance  resolutions approaching 10 keV FWHM attainableT Davinson

  17. TSR@ISOLDE – Injection of RIBs into ring at MeV/u energies Spokesperson K Blaum (MPIK) entire issue of EPJ 207 1-117 (2012)

  18. ISOLDE site (west) side 23.3m 24.6m 3m Proposed layout to fit the TSR at the west side: - Installation above the CERN infrastructure-tunnel 18

  19. The 15O(,)19Ne reaction: the nuclear trigger of X-ray bursts Reaction regulates flow between the hot CNO cycles and rp process  critical for explanation of amplitude and periodicity of bursts

  20. The Hot CNO Cycles Key unknown - α-decay probability from excited state at 4.03 MeV in 19Ne compared to γ-decay, predicted to be ~ 10-4

  21. Study of the p(20Ne,2H)19Ne transfer reaction on the ESR@GSI PJW, Y Litvinov et al. 10820Ne ions @ 50 MeV/u 8 m ESR Electron cooler 1013 H2/cm2 gas target

  22. A few hours of data from test run on ESR DT Doherty, PhD Thesis (2014)

  23. Nucleosynthesis above Fe Se p, νp, rp-process? Ge ~1% Zn Ni r-process Fe tb>tng ~50% s-process: tb<tng ~50%

  24. Puzzle of the origin of heavy ‘p-nuclei’ – abundant proton-rich isotopes eg 92Mo and 96Ru Supernova shock passing through O-Ne layers of progenitor star

  25. Predicted p-process abundances compared to observed abundances Arnould & Goriely Phys. Rep. 384,1 (2003)

  26. Study of 96Ru(p,γ)97Rh reaction with decelerated beamsusing the ESR storage ring at GSI Fully stripped 96Ru44+ ions Gas Stripper ions injected @ 100 MeV/u Reduced to ~10MeV/u Carbon Foil Stripper

  27. Particle detectors Gas jet Pioneering new technique on ESR (Heil, Reifarth) – heavy recoils detected with double-sided silicon strip detector (Edinburgh) Position distribution of recoiling ions measured by DSSD σ(p,γ)= 3.6(5) mb ~10 MeV/u New DSSD system being developed (Edinburgh/GSI/Frankfurt) for use in UHV on ESR to measure p-processcapture reactions in Gamow burning energy region – test run Autumn 2014.

  28. Observations of Elemental Abundances in old metal poor stars:  Evidence for robust r-process mechanisms (C. Sneden, J.J. Cowan, et al.)

  29. However, for elements below Z ~50 eg Yttrium evidence of need for a secondastrophysical mechanism/site

  30. Sites of the r-process r-process related to environments with high-neutron density and high temperature. Type II supernovae prime suspects… Neutron star mergers and accretion disks in g-ray bursts promising alternatives. Not enough is known at present about the physics to create realistic models

  31. First direct evidence for neutron star merger - kilonova Hubble space telescope images of afterglow of a gamma-ray burst, Berger et al. arXiv:1306

  32. Accessing the r-process path @ RIKEN and FAIR b-delayed n-emissionbranchings(final abundances) b-decay half-lives(progenitor abundances, process speed) Masses (Sn)(location of the path)

  33. Advanced Implantation Detector Array (AIDA) will be used for decay studies of r-process nuclei at RIBF and FAIR Compact high density ASIC electronics instrumentation for multi-channel Double-sided Silicon Strip Detectors (DSSD) AIDA Test at RIKEN May 1st for 10 days 238U fission fragments from BIG RIPs @ RIKEN

  34. First full use of AIDA system will be in conjunction with EURICA gamma-ray array on BIG RIPs separator@RIKEN  Accepted proposal, PI Alfredo Estrade to measure simultaneously masses, half-lives and spectroscopy of nuclei in N~56 region of r-process Are nuclear shell effects responsible for anomalous abundances of light r-process elements in metal poor stars? Double shell closure at 90Se56 ?

  35. BRIKEN collaboration formed for proposed campaign ofβ-n measurements on Big RIPS separator@RIKEN Also plans to couple to Total Absorption Spectroscopy system  GT – strength function measurements

  36. Direct and indirect neutron induced reaction studies • Direct studies with small radioactive target samples will benefit from the new EAR-2 n_ToFfacility @ CERN and the high intensity FRANZ facility@Frankfurt • New ideas should be explored for ‘neutron targets’ for RIBs egReifarth/Litvinov storage ring/reactor idea PR ST- accelerators and beams 17, 014701 (2014). • Indirect/surrogate methods egCoulex ( eg R3B@FAIR), transfer reactions (eg TSR@ISOLDE) need to be explored in much greater depth for reproducing (n,γ) reactions with radioactive species.

  37. Summary • variety of techniques and facilities needed to address key reactions and properties of unstable nuclei for explosive nuclear astrophysics • need world class ISOL and fragmentation facilities in Europe to lead this burgeoning area of science

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