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The FARCOS project. Collaboration: INFN (CT, LNS, MI, NA; Italy), GANIL (France), Un. Huelva (Spain) Synergies: Fazia, Neutron detectors, Spectrometers, …. Physics case: dynamics and spectroscopy. Imaging in heavy-ion collisions Spectroscopy of exotic nuclei:
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The FARCOS project Collaboration: INFN (CT, LNS, MI, NA; Italy), GANIL (France), Un. Huelva (Spain) Synergies: Fazia, Neutron detectors, Spectrometers, …
Physics case: dynamics and spectroscopy • Imaging in heavy-ion collisions • Spectroscopy of exotic nuclei: • In heavy-ion collisions MPCS: Multi-Particle Correlation Spectroscopy • Direct reactions
FARCOS: Femtoscope ARray for COrrelations and Spectroscopy Double-sided Silicon Strip 6.4 x 6.4 cm2 4 cm 1500 m 300 m CsI(Tl) + D 32 x 32 32 x 32 Angular resolution: ~0.2o at d=60 cm
Farcos as a modular correlator Correlations Event characterization (4) Coupling to 4 detectors for dynamics studies (LNS, GANIL, NSCL-MSU, …)
Beam TARGET 30° 176° 1° 1m Chimera @ INFN LNS 1192 Si-CsI(Tl) Telescopes
Particle identification (as in Chimera) Be Li HI t a V(t) 3He t d p CsI (Tl) PSD in CsI(Tl) Z and A for light charged particles ΔE(Si)-E(CsI) Charge Z for particles punching throught the Si detector slow fast ΔE(Si)-ToF Mass for particles stopping in the Si detector 3-12 cm Si ~300 μm 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
Farcos array features • High angular resolution (<0.5o): • 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)
??? Many approaches… large uncertainties Microscopic many-body, phenomenological, variational Density dependence of the asymmetry term in nuclear EoS B.A. Li et al., Phys. Rep. 464, 113 (2008)
skins Lassa @ MSU Imbalance ratios halos FOPI @ GSI Elliptic flow resonances GDR & PYGMY RESONANCE Chimera @ LNS Competitiion Inc. Fusion / DIC Supernovae, neutron stars Symmetry Energy: who cares?
Sec. decays! n p Expansion Ebeam<100 MeV Multifragmentation Pre-equilibrium n,p • n/p energy spectra and angular distributions • p-p, n-n and n-p correlation functions • Isospin diffusion, fractionation, isoscaling phenomena… • Chimera@INFN, Indra@GANIL, Lassa@MSU, … Producing density gradients Large N/Z to enhance effects of Esym() 124Sn+124Sn (N/Z=1.48), 48Ca+48Ca (N/Z=1.4), 197Au+197Au (N/Z=1.49) Radioactive beams…
Heavy-ion collisions: open issues • Pre-equilibrium neutron/proton emissions: the most sensitive probes of Esym() • 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”
qrel Sensitive to space-time properties 1+R(q) 1+R(q) 6Li proton-proton deuteron-alpha Low q (qrel) measurements q (MeV/c) q (MeV/c) Resonances High angular resolution required! Correlation femtoscopy in HIC Femtoscope
Fast simultaneous emitting sources (pre-equilibium) 14N+197Au E/A=75 MeV Slow sequential emissions (evap.) Source size Space-time images Source function: Spatial distribution of proton emitting source in HIC: “femtoscopy” - measuring sizes r~1 fm and times t~10-21s Imaging correlations, “Femtoscopy” G. Verde et al., PRC65, 069604 (2002) q e
d- d- p-p a-6Li Images p-p 1+R(E*) S(r) 6Li- E*(MeV) r (fm) Farcos for complex particle correlations Different particles emitted by different sources and at different times (hierarchy) Event characterization required ! ==> Coupling to 4 mandatory
Not only EoS… 10C* Several unbound species in just one single experiment! Expansion Multi-Particle Correlation Spectroscopy (MPCS) HIC and correlations as a spectroscopic tool
Event mixing Modified event mixing 3-alpha correlation function Spin of 8B states 12C states: sequential decay F. Grenier et al., NPA 2008 W.Tan, PRC 2004 LASSA data C+Mg, E=53 MeV/u Indra data MPCS: 8B and 12C 12C 12C Be 8B p+7Be J=1+ Accessing spins and branching ratios (sequential decay paths) Multi- correlations: Hoyle and Boson condensate states
1+R(Ek) 10C 6Be+ (2p+) 10C 8Be+p (+)p 10C 9B+p (+p)p 2 4 6 8 10 12 14 Disentangle sequential decay paths Ek (MeV) 2-2p correlations: states in 10C* 10C p-p- four-particle correlations 6Be 9B 8Be F. Grenier, A. Chbihi, G. Verde et al., Nucl. Phys. A811 (2008) 233
Symmetry potential Asy-stiff neutron-neutron pp Sources 7 5 Asy-soft Imaging 3 Asy-stiff: more localized source 1 1.5 1.0 1+R(q) 0.5 proton-proton 0.0 4 proton-neutron 3 2 1 q (MeV/c) Symmetry energy and pp, nn and np correlations 52Ca+48Ca E/A=80 MeV Future perspectives: pp, nn, np correlations! Coupling to neutron detectors
neutron-proton Neutron-proton correlation expts Ghetti et al,PRC 69 (2004) 031605 Protons Neutrons Emission chronology sensitive to Asy-EOS …difficult experiments
M.B. Tsang et al., PRL102, 122701 (2009) n/p experiments @ MSU 112Sn+112Sn vs 124Sn+124Sn E/A=50 MeV M. Famiano et al., PRL97, 052701 (2006) p detectors DE-E (Lassa) n detectors Liquid scintillators n/p spectra ==> 0.7
Spectroscopy: “stand-alone” mode Shell structure close to drip lines Must2 expts Example: 8He beam @ Spiral (GANIL) E/A=15.4 MeV 8H + p 7He + d 8H + p 6He + t Similar experiments at LNS (FRIBS) or at LNL(SPES) Spes: low energies (Pulse shape on 1st Silicon)
Spectroscopy: “coupling” mode FRIBS beams at the LNS of Catania 34Ar+p33Ar+d Correlator (33Ar residue) Chimera (d) d 34Ar 33Ar Day-1 experiment at the INFN-LNS • Heavy core: Magnex at ~ 0o • Scattered d with Correlator • Spiral/Spiral2, Spes, … Correlator
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.)
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