Ancillary/Complementary detectors for the AD at LNL

Overview

• The magnetic spectrometer PRISMA• The heavy-ion detector DANTE• The multiplicity filter HELENA

The PRISMA spectrometer

• Formed by a Quadrupole, a Dipole and heavy ion detectors (MCP, MWPPAC, IC) to track the ions.

• Identifies the nuclei produced in the reaction (A,Z,β)

I C

MWPPAC

I C

MWPPAC

Spettrometro PRISMA

Optical elements

● Quadrupole: a singlet, focuses

vertically the ions towards the

dispersion plane

● Dipole: bends horizontally the

ions with respect to their magnetic

rigidity (Br)

PRISMA detectors

● Entrance Position

position xs - ys, time

● Focal Plane Position

position xf - yf, time

● Ionization Chambers

energy loss, total

energy

Physical Event:

(xs, ys, xf, yf, TOF, ∆E, E)

ΔΩ = 80 msr ΔZ/Z 1/60 (Measured) ΔA/A 1/190 (Measured)

Energy acceptance ±20% Bρ = 1.2 T.m

6m (TOF)

Quadrupole Dipole

MWPPAC

IC

Angular range 0o - +130o

Start detector

E-ΔE

X-Y, time

X-Y, time

The CLARA-PRISMA setup

The DANTE array •DANTE (heavy ion detector based on MCP) reveals the position interaction

(position resolution 1mm) of the recoils Doppler correction.

•DANTE placed at the grazing angle for binary reactions γ-γ coincidences

CLARA

Beam74° 26°

Grazing angle

PRISMA

Beam

Detector Array for multi Nucleon Transfer Ejectiles

MCP (50x70mm) detectors

DANTE in the RC of CLARA

Performance of DANTE Need of a kinematical coincidence

Reaction: 64Ni on 238U at 440 MeV, Θgrazing=73o

No possible kinematic coincidence (238U → fissions). As a consequence there is a large background

Performance of DANTE Statistics gamma-gamma

Reaction: 70Zn on 238U at 460 MeV, Θgrazing=64o

Statistics

Energy resolution 1.2%

A. Gottardo, Tesi di Laurea, Universita di Padova

Energy resolution 0.9%

DANTE-CLARA Simulations

•Simulations made with GEANT4 using Enrico’s code for the CLARA array

•Velocity distribution of the recoils, DANTE does not measure the velocity.

•An average velocity of 8% which presents Δβ = 20% gives an ERESOLUTION=2.0%

Velocities measured event-by-event with PRISMA

Inelastic channel

DANTE for the AGATA Demonstrator

New delay line made with componentsDANTE in the new reaction chamber of AD

Milano - LNL

•Versatility of DANTE, different configurations

Padova-LNL

The ancillary DANTE Detector array for multi-nucleon transfer ejectiles

Ring for DANTE built in Al

Low γ absorption

PRISMA

Beam dump

INFN-Milano-LNL

B.Million, S. Coelli, A. Gadea

The DANTE array

Versatility of DANTE

Use of different configurations depending on the Grazing angle of the reaction

26o

42o58o

90o74o

The ancillary HELENA Multiplicity filter

•Helena: 35 hexagonal BaF2 3”x3” detectors•Five ensemble of 7 detectors arranged as a honeycomb•Total solid angle: 57% of 4π (15 cm from target)•Total efficiency: 35%

INFN-Milano

The ancillary HELENA Multiplicity filter: Performance

High Multiplicity Low Multiplicity

Mγ=30 Mγ=5

•PRISMA ancillary detector for AD provides (A,Z,β)

•DANTE ancillary detector for AD provides position interaction and average β → Doppler correction.

•HELENA ancillary detector for the AD provides the multiplicity of the event.

Summary & Conclusions

The DANTE detectors

Linea di ritardo

Lateral section

Thickness:13mm

Delay line

MCP

Mylar

Preamplifier in vacuum

Configuration of a single detector

Test done with an α source

•Time resolution 130ps (TAC-ADC)

•Position resolution <1mm

•High counting rate

•High noise rejection

Test of the DANTE detectors

TOF X coordinate

Y coordinate Amplitude