FARCOSFemtoscope ancillary Array for Correlations & Spectroscopy
G. Verde, INFN-CataniaEXOCHIM collaboration, INFN (LNS-CT-MI-NA), Un.
Messina, GANIL, GEM-UHU, open collaboration1
• Why need for a new project for the reaction
program at INFN-CT and LNS?
• Farcos and present status (mechanics,
electronics)
NN2012
Physics topics1. Heavy-ion collisions (stable and RI beams)
– Dynamics (HBT, Femtoscopy)
• Low & Intermediate energies: fusion, fission, DIC, Symmetry energy, Emission time-scales, probes of reaction models
– Multi-particle correlation spectroscopy (MPCS) cluster states
2. Direct reactions with RIBs– Inverse and direct kinematics
• Nuclei close to drip lines
Chimera: isospin and dynamics
1m
1°
30°
TARGET
176°
Beam1192 Si-CsI(Tl) Telescopes 18 rings in the range 1° ≤ θ ≤ 30°
17 rings in the range 30° ≤ θ ≤ 176° (sphere)High granularity and efficiency up to 94% 4π
• Z identification up to beam charge (ΔE-E)• Z and A identification by ΔE-E up to Z ≤ 9• Z and A identification in CsI up to Z ≤ 4• Mass identification with low energy threshold (< 0.3 MeV/u) by ToF• Z identification for particles stopping in Si (pulse shape)
• Based on (62x64x64 mm3) clusters• 1 square (0.3x62x62 mm3) DSSSD 32+32 strips• 1 square (1.5x62x62 mm3) DSSSD 32+32 strips• 4 60x32x32 mm3 CsI(Tl) crystals
4 CsI(Tl) crystals (3rd stage) DSSSD 1500 μm (2nd stage)
DSSSD 300 μm (1st stage) Assembly
cluster
132 channels by each cluster
FARCOS TELESCOPE – phase 1
Fully reconfigurable (more Si layers, neutron detection, …)
+ Coincidence pairs
+ Uncorrelated pairs
Deuteron-Alpha correlations
Y12
(q)
Relevance of angular resolutionFinal-state interactions
Coulomb FSI: anti-correlation at small q values
Nuclear FSI: correlation at q=42 and 84 MeV/c
High angular resolution required: Low q and resonances
1+R
(q)
q (MeV/c)
deuteron-alpha
6Li
q (MeV/c)
Dedicated RIB experiment
Multi-particle decay spectroscopy
Using heavy-ion collisions as an explorative spectroscopy tool: several unbound species in one single experiment
8B*7Be
p
10C* αp
pα
12C* α α
α
Expansion
Not only EoS…
p5Li*
α
BC states in 12C, 16O, etc.????
A. Raduta et al., Phys. Lett. B705, 65, 201140Ca+12C, E/A=25 MeV @ Chimera
G.S. of 12C 3 alphaΓ~ 7.5% direct three-body decay (BC?)
…but more recently…J. Manfredi et al., PRC85, 2012!!Γ<0.5% direct three body decay!
High resolution measurements (HiRA, pixelated detectors) can lead to totally different results…
FARCOS detectors
•Double-Sided Silicon Strip Detectors•300 μm and 1500 μm•Capton cable and 2x32pin connectors
•Highly homogenous CsI(Tl) crystals •Wrapping: 0.12mm thick white reflector +50μm aluminized Mylar.
•2μm thick aluminized Mylar window at the entrance (0.29 g/cm2)
•Read-out by photo-diodes (300μm)
Single cluster
4 CsI(Tl) crystals (3rd stage)
DSSSD 1500 μm (2nd stage)
DSSSD 300 μm (1st stage)
photodiodes
Mounting allows for addition of other detectors and neutron “transparency”
First prototype modules built4 clusters expected to be ready by the end of 2012
March-April 2012
Geometric flexibility
beam
beam
Cross geometry centered on the beam axis (10 clusters) Wall geometry placed at 45° from
beam axis (9 clusters)
45°
TransportabilityModularity
Geometries
Farcos
Chimera
Chimera rings
Farcos
• Correlations in central collisions (cluster states, HBT, Asy-EoS)
• Correlations in Quasi-Projectile breakup• Spectroscopy with radioactive beams
Projectile fragmentation beams
Experiments with exotic beamsEx: Primary beam: 20Ne E/A=45 MeV/A Production target: 9Be (500 mm)Fragments transported and tagged event-by-event by E-ToF
DSSD Tagging detector
Di-proton decay from excited 18Ne states G. Raciti et al., PRL (2008)
Primary beam : 18O at 55 MeV/A, I~5x1011 part/sec Production target: 9Be (1.5 mm)
Beam production
6He T (ns)
9Li
12Be
15B10Be
DE
(MeV
)
Bρ=2.97 Tm
I (kHz)15B 0.3 14B 0.912Be 1.5 optimized9Li 2.0 8Li 1.6
10Be
16C
13B12Be9Li6He
17C
7LiT (ns)
DE
(MeV
)
I (kHz)16C 4017C 4 13B 23 11Be 6 (optimized)10Be 21 8Li 11Energies: ~ 40-50 MeV/AMomentum window P/P <1%
Bρ=2.71 Tm
11Be
6He8He
11Li
14Be
DE
(MeV
)T (ns)
Bρ=3.8 Tm
I (hz)14Be 411Li 209Li 408He 80 optimized6He 980
G. Cardella et al.
Direct reactions with exotic beams
FRIBS exotic beams34Ar + p 33Ar + d
Farcos (33Ar residue)
33Ar
34Ard
Chimera (d)
Day-1 experiment at LNS
Direct reactions in inverse kinematics
Farcos
Eden neutron array (Orsay) already installed at LNS
Also for Esym(ρ) experiments
• Heavy residue (forward): Magnex• Ligh charged particles: Farcos• Neutron: EDEN, others
Required identification performances (Chimera-like)
Compact preamplifiers – Phase 1
18
32 channels Hybrid charge preamplifiers in a volume ofabout 8cm x 10cm x 2mmm
• Low power consumption: ~750 mW pwe 32 channels (simplify cooling operations)
• Rise-Time (pulser): ~ 3-7 nsec for Cinput=0-100pF• Energy resolution (pulser) ~ 4.3 KeV for Cinput=0-100pF• Available with several sensitivities (5, 10, 45, 100 mV/MeV…)
INFN, Milano – C. Boiano, R. Bassini
First test with beams – July 2012Chimera sphere
p,α + p, d, C E/A=40, 80 MeV Transfer reactions
• CsI(Tl) uniformity• Silicon resolution• Integrating DAQ into Chimera system
Rochester
GANIL
FARCOS
Electronics plans for phase 2• Pre-amplifiers with multiple gains and large dynamic range
(MeV to GeV)• Pulse-shape capabilities
– Low identification thresholds for low energy experiments (Spiral2, Spes)
• Digitalization of detector signals• Update possibilities
– Solid angle increase– Coupling to different detectors (in different
laboratories)
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Neutron detection
• “Transparency” of materials and electronics boards to incoming neutrons
• Stacks of Silicon+Plastic for neutron detection – under study at the moment…
P P P P P
Si
…..
DSSSD1
DSSSD2
CsI(Tl)
CsI(Tl)
Electronics
FARCOS-collaborationPARTICIPANTS
L. Acosta1, T. Minniti2,3, G. Cardella4, G. Verde4, F. Amorini1, A. Anzalone1, L. Auditore2,3, M. Buscemi1,5, A. Chbihi6, E. De Filippo4, L. Francalanza1,5, E.
Geraci4,5, C. Guazzoni7,8, E. La Guidara4,9, G. Lanzalone1,10, I. Lombardo1,5, D. Loria2,3, I. Martel11, E.V. Pagano1,5, A. Pagano4, M. Papa4, S. Pirrone4, G. Politi4,5, F. Porto1,5, L. Quattrocchi2,3, F. Rizzo1,5, P. Russotto1,5, A.M. Sánchez-Benítez11, J.A.
Dueñas11, R. Berjillos11, S. Santoro2,3, A. Trifirò2,3, M. Trimachi2,3, M. Vigilante13,14.
INSTITUTIONS1INFN-LNS; 2INFN- Gruppo Collegato di Messina; 3Dip. Fis. Univ. Messina;
4INFN- Sez. Catania; 5Dip. Fis. e Astr. Univ. Catania; 6GANIL, CEA-IN2P3-CNRS, Caen, France; 7INFN- Sez. Milano; 8Dip. Fis. Univ. Milano; 9CSFNSM, Catania; 10Univ. KORE, Enna, Italy; 11Univ. de Huelva, Spain; 13INFN- Sez. Napoli; 14Dip.
Fis. Univ. Napoli.
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