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 topics

1. 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* αα

α

Expansion

Not only EoS…

p5Li*

α

BC states in 12C, 16O, etc.????

A. Raduta et al., Phys. Lett. B705, 65, 2011

40Ca+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

(M

eV)

Bρ=2.97 Tm

I (kHz)15B 0.3 14B 0.912Be 1.5 optimized9Li 2.0 8Li 1.6

10Be

16C

13B12Be9Li

6He

17C

7Li

T (ns)

DE

(M

eV)

I (kHz)16C 4017C 4 13B 23 11Be 6 (optimized)10Be 21 8Li 11Energies: ~ 40-50 MeV/AMomentum window DP/P <1%

Bρ=2.71 Tm

11Be

6He8He

11Li

14Be

DE

(M

eV)

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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