soft collective excitations in weakly bound nuclei studied with eli-np
DESCRIPTION
Soft collective excitations in weakly bound nuclei studied with ELI-NP. Krasznahorkay Inst. of Nuclear Research of the Hung. Acad. of Sci. (ATOMKI). ELI Attosecond Light Pulse Source. To generate X-UV and X-ray fs and atto pulses, … ATTOSECOND section - PowerPoint PPT PresentationTRANSCRIPT
Soft collective excitations in weakly bound nuclei studied with ELI-NP
A.Krasznahorkay
Inst. of Nuclear Research of the Hung. Acad. of Sci. (ATOMKI)
ELI Attosecond Light Pulse Source
1) To generate X-UV and X-ray fs and atto pulses, … ATTOSECOND section
2) To contribute to the technological development towards 200PW… High-intensity section
Attosecond Beamline
THZ & appl.Gas HHG:
Atto & XUVApplications
OPA chain / stagesCW DPSSL pump
50 mJ / 10 kHz
1J / 1 kHz Solid HHG:Atto & X-Ray
SynchronizedAtto/PW Facility
PW applications
10 mJ / 10 kHz @ mid-IR
10 PW/ 300J/ 0.1HzHigh-intensity Beamline
OPA chain / stages I-VIPulsed DPSSL pump
Ti:SapphireFlashlamps
5 J / 10 Hz
1J / 100Hz
2x Oscillator+ front end
10 kHz
Attosecond Beamline
THZ & appl.Gas HHG:
Atto & XUVApplications
OPA chain / stagesCW DPSSL pump
50 mJ / 10 kHz
1J / 1 kHz Solid HHG:Atto & X-Ray
SynchronizedAtto/PW Facility
PW applications
10 mJ / 10 kHz @ mid-IR
10 PW/ 300J/ 0.1HzHigh-intensity Beamline
OPA chain / stages I-VIPulsed DPSSL pump
Ti:SapphireFlashlamps
5 J / 10 Hz
1J / 100Hz
2x Oscillator+ front end
10 kHz
1. High resolution study of the soft dipole resonances
2. Determination of the strengths of the pigmy dipole resonances
Grand Raiden with complete dispersion matching techniques. The relative energy resolution is the best in the world (ΔE/E ≈ 10-5 ).
The spectrometer was set at 0° and 2.5° with an opening angle of ±20 mrad horizontally and ±20 mrad vertically defined by a slit at the entrance of the spectrometer.
Research Center for Nuclear Physics (RCNP), Osaka University.(3He,t) charge exchange reaction.400 MeV 3He on 40Ca, 42Ca, 44Ca and 48Ca targets.
Previus experiment
We determined the precise level energies for each isotopes and deduced their intensities by fitting the energy spectra.
Identification of new excited states
Energy (MeV)
Counts
Angular distributions
ϴ (deg.)
Low-lying dipole strengths
Super fluid vibrations?Alpha condensate?
B. Cederwall et al., Nature 469, 68-71 (2011)
RPA calculations
• The theoretical description (RPA of the distribution is in progress (Elena Litvinova, GSI)
Theoretical description (RPA) Elena Litvinova, GSI
Comparison of the experimental and theoretical results
A new step with ELI-NP
• Pure electromagnetic probe for exciting exclusively the dipole strengths
• γ-beam combined with the chrystal spectrometer (GAMS4 from ILL Grenoble)
• Ultimately high energy resolution (ppm) allows to measure the natural widths (Γ) of the levels and determine the absolute strengths for a large number of transitions for the first time!
• A new experimental window will be opened to discover new phenomena in nuclear structure physics!
Constraining the symmetry energy of the EoS by precise neutron-skin thickness measurements
Accepted SIS18 experiment (S408), Spokeperson: A. Krasznahorkay
Furnstahl, Nucl. Phys. A706 (2002) 85
The symmetry energy in nuclear matter
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0402
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pa
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ZN
Dipole strengths exited in (p,n) reactions in inverse kinematics
pnGDRGDR rZrNSS 22
2
9
Study of pigmy resonances
Constraints on the symmetry energy and neutron skins from pygmy resonances in 68Ni and 132Sn (PRC 81, 041301(R) (2010))
S(ρ)|ρ=ρ0 = L/3ρ0
Experimental requirements
• High resolution (10-6) tunable photon beam
• Detectors with very high counting rate capabilities
• Flesh ADCs with high (1-2 GHz) sampling rate
• Good collimators and very well shielded beam dump
The GAMS4 flat crystal facility (E.G. Keller et al., NIM A457 (2001) 187.)
Michael Jentschel
Advantages of LaBr3 scintillators
• Best energy resolution
• Fast emission
• High count rate capabilities
• Excellent radiation hardness
• Wavelength of emission max. [nm] 380
• Primary decay time [ns] 16
• Light yield [% of NaI(Tl)] (for γ-rays) 165
M. Ciemala., … A. Krasznahorkay et al., NIM A608 (2009) 76.Fast anti-coincidence shield is
needed to get better response at high energy !!!
Energy resolution and efficiency
Typical time resolution: 250 ps (for large detectors)Spacial resolution <80 cm !!!Scattered background could be reduced
Experimental arrangement
E7 8x8 m
E8 5x8 m
GAMS 4 3x4 m
Shilded beam dump
4 pcs of 3”x3” AC LaBr2 detectors
Cost estimates for detectors: 4x40 k€+ acquisition system: ~ 40 k€
Thank you for your attention