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
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