Open questions and issues in nuclear astrophysics
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Open questions and issues in nuclear astrophysics. Kerstin Sonnabend Darmstadt, Germany Presented by: Michael Hass, Weizmann, Israel. And the role of EURISOL…. CARINA C hallenges and A dvanced R esearch I n N uclear A strophysics. Carmen Angulo. Kerstin Sonnabend

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Open questions and issues in nuclear astrophysics

Kerstin Sonnabend

Darmstadt, Germany

Presented by:

Michael Hass, Weizmann, Israel

And the role of EURISOL….


CARINAChallenges and Advanced Research In Nuclear Astrophysics

Carmen Angulo

Kerstin Sonnabend

Institut für Kernphysik, TU Darmstadt, Germany


CARINA activities

  • Two CARINA workshops organized:

    • First workshop: „Perspectives in European Nuclear Astrophysics“, Parador d‘Aiguablava, Girona, Spain, June 8th - 10th, 2005

      • 39 participants from ten countries

      • five review talks on astrophysical models (explosive burning and AGB/quiescent burning), nuclear models for astrophysics, experiments with RIB at LSF, and experiments at small facilities

      • short talks and discussions in working group sessions (plenary)

      • summary of the conclusions:

        • large variety of problems needs large variety of methods

        • specific tools needed for different nucleosynthesis scenarios

        • small-scale facilities as ‚feeders‘ to large-scale facilities

        • establish a ‚flagship‘ ISOL-type facility for nuclear astrophysics with gas targets, recoil separator, spectrometer, solid-state detectors, and g-ray detection systems available

        • find tentative lists of astrophysical sites and nuclear models for nuclear astrophysics


CARINA activities

  • Second workshop: „Frontier Research in European Nuclear Astrophysics“, Spaulomont, Spa, Belgium, April 25th - 28th, 2007

    • 37 participants from 13 countries

    • 21 talks and five discussions (plenary)

    • workshop explored opportunities for new European facilities

      • agreement that additional facilities, specifically for nuclear astrophysics, are warranted and needed

      • lively discussion over strategy: should it be a dedicated nuclear astrophysics proposal, or complementary to a general nuclear physics proposal?

      • possibilities include: nuclear astrophysics labs network, an underground accelerator, a dedicated nuclear astrophysics separator for capture reactions, reclamation of radioisotopes, ...


Continuation of the CARINA network within FP7

  • JRA-9 (P.J. Woods & M. Hass)

  • NA-15 (S. Marrone & F. Käppeler)

  • NA-16 (K. Sonnabend & C. Angulo)

  • and tasks of N-NA07 (Theory) related to Nuclear Astrophysics


N-NA06:Nuclear Astrophysics

Coordinator: K. Sonnabend, Darmstadt, Germany

Task 1 – Explosive Nucleo-Synthesis

P.J. Woods, Edinburgh, UK, M. Hass, Weizmann, Israel

Task 2 - Reactions at Low Temperatures

K. Sonnabend, Darmstadt, Germany

Task 3 - Nucleo-Synthesis in neutron capture processes

S. Marrone, INFN Bari, Italy

Task 4 – Nuclear astrophysics annual meeting

ENSAR meeting,

Frankfurt, December 12th, 2007


Novelty & Innovation

  • Concentrate on special issues of interdisciplinary field of research

  • Provide individual solutions for problems of special issues

  • Use already available infrastructures

  • Find and enhance synergetic effects

  • Integrate it all in annual meetings


Task 2 - Reactions at Low Temperatures

K. Sonnabend, Darmstadt, Germany

  • e.g. - Solar reactions

  • Not necessarily RIB

  • Smaller laboratories (local)

  • Underground possibilities (“a la LUNA”)


The SNO (Sudbury Neutrino Observatory) Experiment

A D2O Detector

Elastic

Mostly ne

nx +e-nx+e-

ne + d p + p + e-

charge current

Only ne

nx + d p + n + nx

neutral current

All flavors

YES!!

PRL87, 071301 (2001)

PRL 89, 011301 (2002)

PRL 92, 181301 (2004)

“SMOKING GUN”!!


Current status of S17 - direct capture - determinations

Recognized need for a new WI measurement at low energy…

In progress… 7Be(p,g)8B “saga” not over yet…..


Summary of Coulomb Dissociation S17Results

F. Schümann et al. Phys. Rev. C 73, 015806 (2006)

By Courtesy of T. Motobayashi


·  (7Be,8B) proton transfer at 12 MeV/u

two targets:

10B: S17(0) = 18.4  2.5 eVb (PRL ’99)

14N: S17(0) = 18.0  1.8 eVb (PRC ’99; PRC ‘06)

·13C(7Li,8Li)12C at 9 MeV/u

using mirror symmetry (PRC ‘03)

S17(0) = 17.6  1.7 eVb

Average: S17 =18.2  1.7 eVb

S17astrophysical factor - ANC - (R. Tribble)

Transfer

Determine C2 by

three approaches

8B breakup

  • JLM S17=17.4±2.1 eVb

  • “standard” S17=19.6±1.2 eVb

  • Ray S17=20.0±1.6 eVb

Average: S17=18.7±1.9 eVb

PRC ‘04


Results and Fits

New LUNA Activity Result

-

Phys. Rev. Lett. 97, 122502 (2006)

S34(0) = 0.53(2)(1) keV-b

B.S. Nara Singh et al.,

Phys. Rev. Lett. 93, 262503 (2004).

No compelling need to assume

Systematic difference between

prompt and activity determinations

  • RMS ERNA in Bochum

  • Seattle


Dedicated experiments to measure the 7Be EC lines: Borexino etc…

SNO


b.- Primordial 7Li –SBBN (A. Coc, Orsay)


n_TOF/Astrophysics:present & future

Task 3 - Nucleo-Synthesis in neutron capture processes

S. Marrone, INFN Bari, Italy

[email protected]

www.cern.ch/n_TOF


Nuclear Astrophysics

Re/Os cosmo-chronometer

Red Giants

Nr= Nsolar – Ns

Residual Method

Supernovae

[email protected]

www.cern.ch/n_TOF


The n_TOF-Ph2 experiments

2008 and beyond

(*) endorsed by CERN Isolde-n_TOF Committee, execution in 2008

[email protected]

www.cern.ch/n_TOF


The second n_TOF beam line

NewExperimentalArea (EAR-2)

~ 20 m

present EAR-1

(at 185 m)

Proton Beam

Spallation Target

  • present EAR-1: Flight path ~185 m, Neutron Flux~106 n per proton bunch; High resolution in neutron energy.

  • new EAR-2: Flight path ~20 m at 90° with respect to p-beam; neutron flux enhanced by factor ~100; drastic reduction of backgrounds.

[email protected]

www.cern.ch/n_TOF


  • Task 1 – Explosive Nucleo-Synthesis

  • Identification of the key reactions, including specification of the energy range and

  • precision required for future experimental studies (leading institute: Barcelona).

  • Identification of the key technical developments required to deliver the highest

  • priority radioactive beams to measure these reactions including exchange of

  • technical ideas and coordination, of how and where developments should be

  • best achieved (leading institute: Weizmann).

  • Identification of the key characteristics of design and construction of

  • novel detector and spectrometer systems to measure these reactions

  • including exchange of technical ideas and coordination of single activities

  • (leading institute: Edinburgh).

  • Determination of key features of nuclear properties, nuclear reactions,

  • and the nuclear equation of state for astrophysical simulations and their

  • experimental and/or theoretical verification (leading institute: Basel).


Secondary neutrons + fission

BUT

Also light RIB’s

And SARAF!


Fusion Reactions in the Sun:The CNO cycle

…..

17F

(a,p)

14O

  • Proposed at GANIL


Mass accretion from a companion into a

neutron star (black hole).

  • Role of 14O, 15O and 18Ne in the physics

    of x-ray bursts

M. Wiescher et al. Erice Conference, 2007

J.L. Fisker et al., arXiv:astro-ph/070241

4He(15O,g)19NE


X-Ray Bursts and the “rp” process

The rp process and x-ray bursts - site of nucleo-synthesis

Courtesy of Joint Inst. For Nuclear Astrophysics (US)


Recent Experiments (in progress)

ISOLDE experiment IS424 (Sept. ’07): (in collaboration with P.J. Woods et al.).

  • The use of a 17F beam from the upgraded REX-ISOLDE facility to study the

  • astrophysically important 14O(α,p)17F reaction in time reverse kinematics.

  • REX-ISOLDE + MINIBALL

  • Only ~ 103 17F/s

On-line data of p-g coincidences –

Indicating the 1st excited state of 17F


GANIL experiment – accepted by GANIL PAC : (in collaboration with Marialuisa Aliotta et al.)

Plan to investigate the direct 14O(a,p)17F reaction at four different energies

in the energy region Ecm = 1.0-2.5 MeV

Calculated total S(E) factor.

Constructive (+) and destructive (-)

interference between the Jpp=1-

6.15 MeV state and the direct l=1

partial wave contribution are shown.


Long-learned lesson:

“orders-of-magnitude improvement in sensitivity of measurement –

enhanced understanding and possibilities”.

14N(d,2n)14O cross section and yield 14N(d,n)15O cross section and yield for a 2 mA deuteron beam for a 2 mA deuterons beam

But, extraction of atomic oxygen…


8Li energies of interest

E(8Li [MeV])

6

3


Examples of Reactions with RNB’s for Astrophysics

  • 8B(p,g)9C

  • 8B(a,p)11C

  • 9C(a,p)12N

  • 11C(p,g)12N


Nucleosynthesis in AGB Stars - Maurizio M. Busso Perugia

CNO, Ne-Na, Mg-Al Cycles

Important experimental and theoretical work has addressed the CNO cycle……..

e.g. 14N(p,g)15O (see: Schroeder et al. 1987; Angulo et al. 2001)

Runkle et al. 2002, Phys Rev C 66

Formicola et al. 2004, Phys. Lett. B. 591

Runkle et al. 2005, Phys Rev C 94

…. and of the hotter cycles of H-burning:

e.g. for reacions on O isotopes and Na (leading to Mg-A)

Fox et al. 2004, Phys. Rev. Lett. 93: 17O+p

Rowlad et al. 2004 Phys Rev. Lett 93: 23Na+p


RECENT LUNA ACHIEVEMENTS ON CNO

H.P. Trautvetter, ECT Nuclear Astrop. Workshop, (Trento, May 2004)


Ne-Na and Mg-Al ‘cycles’

(p,g)

(p,a) (p,g)

But; effects on higher nuclei (26Al) limited by minimal of 20Ne

production (at least with NACRE): Arnould et al. 1999.


Finances

  • each specialized task (1 - 3):50 k€

  • general annual meetings:40 k€

  • support of coordinator:4 k€

  • total costs:194 k€


  • General considerations to remember: -

  • It is nuclear structure after all - masses, Q values, lifetimes,

  • reaction theory, ….

  • Nuclear (astro) physics vs. “modeling” and “standard” astro.

  • Nuclear astrophysics as “motif” for many RIB facilities.

  • BUT

  • How much time would a Facility devote to these time-consuming experiments


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