1 / 28

Possibilities for Nuclear Physics at the Madrid Tandem

Possibilities for Nuclear Physics at the Madrid Tandem. Nuclear physics and astrophysics of light nuclei A=9 and A=12 Studies at CERN of the CSIC group What could be done at a tandem?. Hans O. U. Fynbo Department of Physics and Astronomy University of Aarhus, Denmark. ?. Nuclear chart.

selina
Download Presentation

Possibilities for Nuclear Physics at the Madrid Tandem

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Possibilities for Nuclear Physics at the Madrid Tandem • Nuclear physics and astrophysics of light nuclei • A=9 and A=12 • Studies at CERN of the CSIC group • What could be done at a tandem? Hans O. U. Fynbo Department of Physics and Astronomy University of Aarhus, Denmark

  2. ? Nuclear chart N = Z

  3. A=9 and A=12 Nuclei • “Exact” A-body calculations possible for A12 (soon) • Shell-model states • Molecular-cluster states • Break-up mechanism not fixed by kinematics • How does three particles tunnel? • Fundamental QM problem • Crucial for bridging the • A=5 and A=8 gaps in Big Bang and Stellar nuclear synthesis.

  4. Ab-initio Monte-Carlo calculations for A12

  5. Model Predictions (eff. Int.)

  6. The triple-a reaction rate

  7. (ab) + c E,G Direct ? a+(bc) Sequential Energy (ab) + c Y : a+b+c X 12C* 8Be(2+)+a a+a+a 9B 8Be+p, 5Li+aa+a+p 12C* 8Begs+a a+a+a 31Cl*30S+p 29P+2p (ab) + c Break-up to Multi-particle Final States Initial state X : Some (nuclear) state Final state Y : Three (or more) particles

  8. E,G Questions What is : • The mechanism • of the break-up? • -Sequential or • direct? • -Importance of • different channels • Relation to state • structure • E,G ? • -Often difficult to • Measure • Spin-parity? • - Selection rules • The structure • of the state? • -Cluster states • -Many-body states • Assymptotic • Spectra • -Observable • Energy and angular • correlations

  9. 15.9572 11B+p 15.11 1+ 14.08 4+ 13.35 2- 12.71 1+ 11.83 2- 10.84 10.27 1- 10.3 0,2+ 2+ 9.641 3- 0+ 7.6542 7.377 0+ 7.285 7.285 a+a+a a+a+a 12C 8Be+a Width  Decay Structure

  10. ISOLDE @ CERN

  11. ISOL beam • Low energy isotope separated beam • Can be stopped in C-foil • Well-defined source Previous studies using this setup 31Ar 2p Nucl. Phys. A677 (2000) 38 9C 2p Nucl. Phys. A692 (2001) 427 12N 3a Under analysis R.R.Betts IL NOUVO CIMENTO 110A (1997) 975 • Modern segmented Si-Detectors • Large Solid Angle • detect all particles • High Segmentation • no summing • Modern segmented Si-Detectors • Large Solid Angle • detect all particles • High Segmentation • no summing

  12. L. Fraile

  13. Region probed by b-decay 0+, 1+,2+ Region probed by delayed a-emission 12C from the b-decay of 12B Latest evaluation 1990

  14. Dalitz plot E2 E3 E1 Dalitz plot for 3a Q h1= E1 /Q h2= (E1 +2 E2)/Q

  15. Dalitz plot E2 E3 E1 The 12.71MeV state: Dalitz plots Phase space Data Simultaneous stepwise

  16. Simultaneous Stepwise

  17. a a-8Be a 8Be T a-a • Classical calculation • No ang.mom. Included • Need unphysical S PRL 20 (1968) 1178 a Coulomb interaction between 1st and 2nd emitted as neglected !!!!

  18. 2+ state Towards the Astrophysical Region 0+ state 0+ state including interference with ghost anomaly

  19. The triple-a reaction rate

  20. b-decay summary • Selection rules pick out specific states • among possibly many (spin + isospin) • Particles from breakup of unbound states • fed in the decay emitted from rest • Point source • Thin host -> reduced energy loss • Certain states cannot be produced • Time structure of events can be very peaked • Yield is often very limited • Very restricted access to beam

  21. Peaks in p-spectrum  State in 12C Peaks in a-spectrum  State in 9B 10B(3He,p3a)

  22. 10B(3He,p3a) Ea Ep 10Be(3He,n3a)... 1966 Ep

  23. 6Li(6Li,3a) Ea • Reaction mechanism • FSI Coulomb effects Ea 1968

  24. 8Be (0+) 9Be (3He,3a) Ea Ea • Reaction mechanism • FSI Coulomb effects 1965

  25. 13C(3He,4a) Ea Ea Also : 7Li (d,naa), 10Be(3He,naaa), 6Li (3He,paa) 1965

  26. Summary • To study exotic short lived nuclei new • effective detector arrays have been developed • New analysis methods • A number of reactions suitable for tandems • exist which were last visited >30 years ago. • Huge potential for extracting interesting and • very relevant information on light nuclei.

More Related