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The FARCOS project Collaboration: INFN (CT, LNS, MI, NA; Italy), GANIL (France), Un. Huelva (Spain) Synergies: Fazia, Neutron detectors, Spectrometers, …
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Physics case: dynamics and spectroscopy 1.Imaging in heavy-ion collisions 2.Spectroscopy of exotic nuclei: –In heavy-ion collisions MPCS: Multi-Particle Correlation Spectroscopy –Direct reactions
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FARCOS : F emtoscope AR ray for CO rrelations and S pectroscopy 300 m 1500 m Double-sided Silicon Strip CsI(Tl) + D 32 x 32 6.4 x 6.4 cm 2 4 cm Angular resolution: ~0.2 o at d=60 cm
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Farcos as a modular correlator Event characterization (4 ) Correlations Coupling to 4 detectors for dynamics studies (LNS, GANIL, NSCL-MSU, …)
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Chimera @ INFN LNS 1m 1° 30° TARGET 176° Beam 1192 Si-CsI(Tl) Telescopes
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Si CsI(Tl) ΔE(Si)-E(CsI) Charge Z for particles punching throught the Si detector PSD in CsI(Tl) Z and A for light charged particles ΔE(Si)-ToF Mass for particles stopping in the Si detector E(Si)-Rise time Charge Z for particle stopping in Si detectors (NEW) ΔE(Si)-E(CsI) Charge Z and A for light ions (Z<9) punching throught the Si detector HI p d t 3 He Li Be ~300 μm 3-12 cm Particle identification (as in Chimera) V(t) t slow fast
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Farcos array features High angular resolution (<0.5 o ): Flexibility: allow coupling to –4 detectors, magnetic spectrometers, other correlators –Neutron detectors for n-p correlations (future) Low thresholds for low energy experiments at Spiral2 and Spes –pulse-shape on silicon and digitalization (future, interface to Fazia project)
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Density dependence of the asymmetry term in nuclear EoS B.A. Li et al., Phys. Rep. 464, 113 (2008) ??? Many approaches… large uncertainties Microscopic many-body, phenomenological, variational
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Symmetry Energy: who cares? GDR & PYGMY RESONANCE skins halos resonances Supernovae, neutron stars Lassa @ MSU Imbalance ratios FOPI @ GSI Elliptic flow Chimera @ LNS Competitiion Inc. Fusion / DIC
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Isospin diffusion, fractionation, isoscaling phenomena… Chimera@INFN, Indra@GANIL, Lassa@MSU, … n/p energy spectra and angular distributions p-p, n-n and n-p correlation functions Producing density gradients Large N/Z to enhance effects of E sym ( ) 124 Sn+ 124 Sn (N/Z=1.48), 48 Ca+ 48 Ca (N/Z=1.4), 197 Au+ 197 Au (N/Z=1.49) Radioactive beams… Pre-equilibrium n,p Expansion Multifragmentation Sec. decays! E beam <100 MeV n p
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Heavy-ion collisions: open issues Pre-equilibrium neutron/proton emissions: the most sensitive probes of E sym ( ) –n/p relative energy spectra –p-p, n-p, n-n two-particle correlation functions Space-time characterization: different particles emitted by several sources & over different time scales –Need space-time probes to disentangle sources t as short as 10 -22 sec r as small as 1 fm“femtoscopy”
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Correlation femtoscopy in HIC Femtoscope 1+R(q) q (MeV/c) proton-protondeuteron-alpha 6 Li Sensitive to space-time properties rel High angular resolution required! Resonances Low q ( rel ) measurements
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Imaging correlations, “Femtoscopy” Fast simultaneous emitting sources (pre-equilibium) Source size Slow sequential emissions (evap.) 14 N+ 197 Au E/A=75 MeV G. Verde et al., PRC65, 069604 (2002) qe Space-time images Source function: Spatial distribution of proton emitting source in HIC: “femtoscopy” - measuring sizes r~1 fm and times t~10 -21 s
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Farcos for complex particle correlations r (fm) S(r) Images d- - 6 Li p-p Different particles emitted by different sources and at different times (hierarchy) Event characterization required ! ==> Coupling to 4 mandatory p-p 1+R(E * ) E * (MeV) d- 6 Li-
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Multi-Particle Correlation Spectroscopy (MPCS) Expansion HIC and correlations as a spectroscopic tool Several unbound species in just one single experiment! 10 C* Not only EoS…
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MPCS: 8 B and 12 C Event mixing Modified event mixing 3-alpha correlation function 12 C states: sequential decay C+Mg, E=53 MeV/u F. Grenier et al., NPA 2008 Indra data 12 C 12 C Be LASSA data Spin of 8 B states W.Tan, PRC 2004 J=1 + 8 B p+ 7 Be Accessing spins and branching ratios (sequential decay paths) Multi- correlations: Hoyle and Boson condensate states
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2468101214 E k (MeV) 1+R(E k ) 2 -2p correlations: states in 10 C* F. Grenier, A. Chbihi, G. Verde et al., Nucl. Phys. A811 (2008) 233 p-p- four-particle correlations 10 C 6 Be+ (2p+ ) 10 C 8 Be+ p ( + ) p 10 C 9 B+p ( + p) p Disentangle sequential decay paths 10 C 9B9B 6 Be 8 Be
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Symmetry energy and pp, nn and np correlations Asy-stiff Asy-soft Symmetry potential neutron-neutron proton-proton proton-neutron 0.0 0.5 1.0 1.5 1 2 3 4 1 3 5 7 q (MeV/c) 1+R(q) 52 Ca+ 48 Ca E/A=80 MeV pp Sources Asy-stiff: more localized source Imaging Future perspectives: pp, nn, np correlations! Coupling to neutron detectors
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Neutron-proton correlation expts neutron-proton Ghetti et al, PRC 69 (2004) 031605 Protons Neutrons Emission chronology sensitive to Asy-EOS …difficult experiments
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n/p experiments @ MSU n detectors Liquid scintillators p detectors DE-E (Lassa) M. Famiano et al., PRL97, 052701 (2006) M.B. Tsang et al., PRL102, 122701 (2009) 112 Sn+ 112 Sn vs 124 Sn+ 124 Sn E/A=50 MeV n/p spectra ==> 0.7
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Spectroscopy: “stand-alone” mode Example: 8 He beam @ Spiral (GANIL) E/A=15.4 MeV 8 H + p 7 He + d 8 H + p 6 He + t Shell structure close to drip lines Similar experiments at LNS (FRIBS) or at LNL(SPES) Spes: low energies (Pulse shape on 1st Silicon) Must2 expts
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Spectroscopy: “coupling” mode FRIBS beams at the LNS of Catania 34 Ar+p 33 Ar+d Correlator ( 33 Ar residue) 33 Ar 34 Ar d Chimera (d) Correlator Heavy core: Magnex at ~ 0 o Scattered d with Correlator Spiral/Spiral2, Spes, … Day-1 experiment at the INFN-LNS
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Imaging correlations at low energies Perspectives at Spiral2 and Spes: Imaging in fusion, fission, DIC, N/Z effects on limiting temperatures and reaction mechanisms, particle emission chronology Requires low identification thresholds: pulse-shaping techniques on silicon detectors Chimera solution, Fazia implementation (digitalization of silicon signals) Future issue: Pulse-shape capabilities in integrated electronics (ASIC, etc.)
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Workshop in 2011 Catania, probably spring or early fall 2011 –Integrated electronics for silicon detectors, new solutions, pulse-shape in integrated solutions, coupling to different detectors (also neutrons, gammas, spectrometers, …), others You are all very welcome: need to build up synergies
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