Farcos FemtoscopeArray for Correlations and Spectroscopy

Transcription

1 Farcos FemtoscopeArray for Correlations and Spectroscopy G. Verde(INFN-CT), A. Chbihi(GANIL), Exochim coll., INFN- CT, LNS, MI, NA - Open collaboration and synergies.

2 Farcosphysics: dynamics & spectroscopy 1. Heavy-ion collision (stable and RI beams) Dynamics (HBT, Femtoscopy) Low energy: fusion, fission, DIC Intermediate energy: Symmetry energy Multi-particle correlation spectroscopy (MPCS) 2. Direct reactions with RIBs Inverse and direct kinematics Explore drip lines rp-process physics (S p, spins, resonances, )

3 Heavy-Ion collisions Complex but rich systems Dynamics/Thermodynamics EoS, Asy-EoS, Fusion/Fission, DIC, Spectroscopy Unbound states, spins, branching ratios, sequential decay modes

4 HBT applications Final-state interactions ( ) ( ) r Y 1+ R(q) = k coin p1, p r 2 r Y evt.mixing p1, p r 2 Sensitive to space-time properties 1+R(q) 6 Li 1+R(q) High angular resolution is crucial proton-proton q (MeV/c) Low q (θ rel ) measurements deuteron-alpha q (MeV/c) Resonances

5 Imaging correlations, Femtoscopy R(q) = 4π dr r 2 S(r) K(r,q) 14 N+ 197 Au E/A=75 MeV G. Verde et al., PRC65, (2002) Space-time distribution of emitting sources q e Measuring sizes r 1 fm

6 Size matters All energy regimes concerned -from Spiral to RHIC and LHC Both dynamics and structure concerned Dynamics: determine volumes, densities (EoS) Structure: relevance of spatial properties of Halo nuclei (p- and n-drip lines) Probing space-time features of proton emitters (ex. two-proton sequential vssimultaneous, spatial extents of halos)

7 Existing correlators, Femtoscopes Must2 HiRA Wire chambers (high position resolution) T.K. Nayaket al., PRC45, 132 (1992)

8 Basic cell prototype ( ) Double-sided Silicon Strip 6.4 x6.4 cm 2 CsI(Tl)+Φ D 1500 μm 300 μm + thinner? 32 x32 32 x32 Stage A: First modules with classic pulseshape electronics (Chimera) First experiments at the INFN-LNS Stage B: Decisions on integrated and configurable electronics

9 Stage A: exploring different identification techniques ΔE(Si)-E(CsI) Charge Zfor particles punching throught the Si detector V(t) PSD in CsI(Tl) Zand Afor light chargedparticles t HI Be Li 3 He α fast slow p d t Si ~300 μm CsI(Tl) 3-12 cm ΔE(Si)-ToF Massfor particles stopping in the Si detector ΔE(Si)-E(CsI) Charge Z and A for light ions (Z<9) punching throught the Si detector E(Si)-Rise time Charge Z for particle stopping in Si detectors (NEW)

10 Additional array features Multiple stages of Silicon ΔE detection + CsI Pulse-shape capabilities: Low identification thresholds for low energy experiments (Spiral2, Spes, Excyt) Digitalization of detector signals Flexibility: Geometry: coupling to 4π, MagSpec, n-det, γ-det Electronics: integrated, re-configurable, generic Transportability (different labs)

11 Operations with 4π detectors Farcos+ 4π array Correlations Heavy-ion collisions Direct reactions

12 Operations with magneticspectrometers Farcos+ Magnetic spectrometer Direct reactions with stable and RI beams Farcos Fusion/fission studies at low energies: Magnex for fusion residues Explore coupling to neutron and gamma detectors

13 Nuclear symmetry energy E(ρ,δ ) E ρ,δ = 0 ρ n + ρ p ( ) + E sym (ρ) δ 2 δ = ρ ρ n p B.A. Li et al., Phys. Rep. 464, 113 (2008)??? RIBs important Still large uncertainties Relevant to neutron skins, neutron stars, GDR, PDR Need more N/Zasymmetric beams to enhance effects

14 Symmetryenergywith correlationimaging Asy-stiff Sources Asy-soft Correlations Bao-An Li et al

15 First results and puzzles from Ca+Ca collisions Source smaller in symmetric matter (N=Z) than in neutron-rich matter (N>Z) E/A=80 MeV central 40 Ca+ 40 Ca N/Z=1 1+R(q) 48 Ca+ 48 Ca N/Z=1.4 S(r) (a.u.) prelim q (MeV/c) r (fm) Size effect or N/Z effect? How to disentagle?

16 What experiments/beams Small mass systems: A (enhance correlation signals/background) Large N/Z ranges Same A but different N/Z asymmetries (disentangle size and isospin effects) Wide systematics over A Important: RIBs with high intensities, p-rich and n-rich beams to keep A constant

17 Correlations with neutrons Correlation functions IBUU: 52 Ca+ 48 Ca E/A=80 MeV 7 5 neutron-neutron Highly performing and flexible neutron detectors required R(q) proton-proton proton-neutron 2 1 q (MeV/c)

18 Femtoscopyin low energy HIC Dynamics studies of fusion reactions with beams close to p-drip lines Correlation functions Explosive 1+R(q) Evaporative Stabilityvalley q (MeV/c) Multi-particle correlations and test of Weisskopf decay theories Requirement: low identification threhsolds

19 Complex particle correlations 6 Li-α p-p Images d-α 1+R(E * ) d-αα S(r r) p-p α- 6 Li E * (MeV) r (fm) Collective motion (rotation, expansion, etc.) needs special attention (G. Verde et al., Phys. Lett. B653, 12 (2007))

20 Multi-Particle Correlation Spectroscopy (MPCS) Not only EoS 10 C* Expansion Several unbound species in just one single experiment! HIC and correlations as a spectroscopic tool but just a tool! Need dedicated experiments with RIBs anyway! More exotic species for more proton-rich beams

21 MPCS: spins and sequential decay paths 8 B p+ 7 Be 12 C α+α+α (?) 12 C α+ 8 Be α+α (?) Spin of 8 B states J=1 + LASSA data Xe+Au E/A=50 MeV W.Tan, PRC alpha correlation function Event mixing Modified event mixing 12 C states: sequential decay C+Mg, E=53 MeV/u Indra data F. Grenier et al., NPA 2008 Multi-α correlations: Hoyle and Boson condensate states (?????) Be careful with conservation laws 1+R distorted: need RIBs expts

22 2α-2p correlations: states in 10 C* 10 C p + p + α + α p-p-α α four-particle correlations 10 C 1+R(E k ) E k (MeV) F. Grenier, A. Chb bihi, G. Verde et al., Nucl. Phys. A811 (2008 8) Be 8 Be 10 Statistics C 6 Be+α enhanced (2p+α)+α with 9 B proton-rich 10 C 8 Be+2p beams: (α+α)+2p more 10 exotic species and states C 9 B+p (α+α+p)+p can be explored Disentangle sequential decay paths

23 MPCS as a tool for spectroscopy High precision measurements with dedicated experiments (RIBs) required RIB expts with high resolution Charity et al., PRC (R) (2007) Mercurio et al., PRC(R) (2008) Curtis et al., PRC 77 (R) (2008) 10 C+ 9 Be p+p+α+α E/A=10.7 MeV

24 Direct reactions in inverse kinematics Exotic decay modes close to proton-drip line p-separation energies (implications on the rp-process) Operational modes: Stand-alone operations Coupling to magnetic spectrometers or other large arrays (n- and γ-detectors important)

25 First experiments: INFN-LNS Projectile fragmentation beams Ex: Primary beam: 20 Ne E/A=45 MeV/A Production target: 9 Be (500 µm) Fragments transported and tagged event-by-event by E-ToF Di-proton decay from excited 18 Ne states G. Racitiet al., PRL (2008) 20 Na 19 Ne DSSD Tagging detector 17 F 18 Ne 17 Ne 17 F E (ch) 12 C 16 O 12 N 13 N 15 O 11 C 8 B 10 B tof(ch)

26 Fribs-LNS Proton-rich FRIBS beams at the LNS of Catania 34 Ar+p 33 Ar+d Chimera (d) Farcos ( 33 Ar residue) 34 Ar d 33 Ar Day-1 experiment at the INFN-LNS Correlator Coupling to Magnex Farcosto detect light emitted partiles(p, d) or the target residue (pulse-shape identification of low energy particles)

27 Summary of features (we hope!) Telescope: multiple DSSSD + CsI(Tl)/Φ D Several identification techniques (ΔE-E, ΔE-ToF, Pulse-Shaping (ΔE-RiseTime), etc. Low thresholds for low energy experiments (both dynamics and spectroscopy) Flexibile in geometry and electronics Studying solutions for configurable ASIC Transportability (extend physics cases with future RIB facilities) Hope to make low energy experiments possible

28 School & Workshop on FEE, ASIC, configurable electronics Fall 2011 FEE, Integrated electronics, Problems in Signal formation, configurability, generic solutions, firmware programming Future highly segmented detectors Acireale(Catania) Fall 2011 To be announced very soon You are invited ask for more info