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GIANT RESONANCES, NEUTRON SKIN

• Krasznahorkay, M. Csatlós, J. Gulyás, M. Hunyadi,
  Z. Máté,
• B.M. Nyakó, D. Sohler, L. Zolnai
• for the ATOMKI, KVI, RCNP, INFN collaboration

Nothing tends so much to the advancement of
knowledge as the application of a new instrument.
-- Sir Humphrey Davy
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History of the collaboration

• Postdoctoral position at KVI (AK, 1989,1990)
• GR studies with magnetic spectrographs
• A split-pole magnetic spectrograph as a present
• NWO OTKA support
• Study of HD states in Debrecen, collaboration
  also with LMU
• Postdoc position at KVI (MH, 2000,2001)
• NWO-OTKA (1994-2002, 49 publications)
• 2002-2007 30 common publications.

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Electric Giant Resonances
Isoscalar
Isovector
1977
1983
Monopole
Dipole
1948
1971
1980
Quadrupole
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Experimental determination of the neutron-skin
thickness
neutrons protons
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The GDR method
?
?
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Hatáskeresztmetszet számolások a GT és SJ modell
alapján
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The experimental setup
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Final state spectra
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Final state spectra for the 208Pb(?, ??)
reaction
NaI det.
Clover det.
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Determination of the neutron-skin thickness of
208Pb
GDR results 0.120.07 fm G.W. Hoffmann et al.,
Phys. Rev C21 (1980) 1488 0.140.04
fm Trzcinska et al., Phys. Rev. Lett. 87 (2001)
82501 0.150.03
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Trzcinska et al., Phys. Rev. Lett. 87 (2001) 82501
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Vibrations in the spin-isospin space Sum rule
for the SDR strength
A. Krasznahorkay et al., Phys. Rev. Lett. 82
(1999) 3216.
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114-124Sn(3He,t) at E 400 MeVat RCNP, Osaka
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(p,p) GDR SDR
A. Krasznahorkay et al., Phys. Rev. Lett. 82
(1999) 3216.
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Experimental methods
BBS
E177 MeV ?3.2o
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Differential cross sections
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Our results obtained with the SDR method
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Isovector GRs in unstable nuclei

• - The physics case
• Macroscopic microscopic info
• Neutron skin
• SDR sum-rule
• Ex(GTR)-Ex(IAS)
• astrophysics e.g. ?-process
• Experimental considerations ((p,n) in inverse
  kinematics)
• High cross sections (10mb/sr)
• Complete kinematics (use FRS)
• low-En, no energy loss in target
• Neutron detection
• aim 1 MeV resolution in Ex
• required ???10 ?En /En 10 flight path 1
  m, Timing resolution 1 ns

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(p,n) in inverse kinematics p(132Sn,n) E400 AMeV
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The ELENA setup

• Type of the scintillator UPS-89 NE102A
• Syze of the scintillator 10x45x1000 mm
• PMTs XP2262 active dividers

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Monte-Carlo simulations
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Conclusions

• GR studies in stable beams
• GR studies in RIBs
• Challenges for the detectors