1. Active Target for the low-energy short-lived radioactive beams
L. Nalpas, CEA Saclay Irfu/Sphn
for the ACTAR & GET collaboration
French Japanese Symposium on Nuclear Structure Problems, Jan 5-8, 2011

2. Time-Projection Chamber
ACtive TARget Concept
Time-Projection Chamber
Reconstruction of the nuclear reaction and
decay products
(x-z) projection on the segmented electrode
(y) from the drift time
High efficiency (4p coverage)
Thick & pure target (small s, L~1026/cm-2/s)
Good spatial resolution (~mm)
Low detection threshold
Track reconstruction from the charge profile qxz(t)
High dynamic range (~1000)
High granularity (pad size ~mm2)
Low noise, low threshold
Sampling (time-dependence)
T. Roger, H. Savajols, MAYA, Ganil

3. Physics cases Direct reactions Resonant reaction Giant resonances
1-, 2-nucleon transfer (d,p) (3He,d) (d,a) (p,t)…
Inelastic reaction (p,p’) (d,d’) (a,a’)
Possible coupling with g detection (PARIS like)
Charged particle detection (MUST2 like)
103-4 pps (exotic beams at low energy)
SP2 LoI phase-2 134,135Sn 80Zn (d,p) 5 MeV/n
Resonant reaction
SP2 LoI phase-2 26Ne (p,p) 5 MeV/n
Excitation of the resonances in 27Na (IAS of 27Ne)
particle detection at forward angle
Giant resonances
Nuclear compressibility
68Ni (a,a’) 50 MeV/n Ea~1 MeV
Exotic decay around the dripline
2p-decay study 45Fe, 54Zn, 59Ge
2-step process, high granularity
Nuclear astrophysics
SP2 LoI phase-2 60Zn 64Ge p-capture
25Al 30P (p,) 60Zn 102In (3He,d)

4. 134Sn (d,p) Transfer reactions with solid C3D6 target at low energy
V. Lapoux, Must2 simulation
134Sn (d,p) 3 4
Low-energy proton (<5 MeV)
Large angular range
Strong target effects (threshold, straggling)
Excitation energy (g-detection)

5. Simulations 78Ni(d,p) @ 8 MeV/n ActarSim
shtml
(Geant4 & ROOT)
drift, diffusion,
amplification and induction
for each track
DE~2 MeV/n (pure D2, 1 atm)
4x4 mm2 pad
p stopped in the gas
(>120°, Rmin> 2cm)
Vertex resoln: 1 mm
Exc resolution: ~250 keV
Feasible with beam intensity 103 pps
H. Alvarez Pol, E.A. Benjamin, D.Y. Pang
GANIL, Santiago de Compostela univ.

6. ACTAR Status FP6 JRA program – LoI SP2 Simulation ActarSim
20 institutions (Ganil, Saclay, IPN, CENBG, LPC, GSI, Soltan Institute, Warsaw Univ., St de Compostela Univ., Huelva Univ., Surrey Univ., Birmingham Univ., Edinburgh Univ., Liverpool Univ., York Univ., K.U. Leuven, CERN, MSU )
Simulation ActarSim
Geometry of the TPC (cylindric, cubic)
Gas mixtures (gain, drift)
Pad design for position measurement
Reconstruction algorithms
Design study
Amplification
Prototype of a µMegas bulk
R&D program for electronics (GET)
Pad size 2x2mm2
Amplification with µMs
GANIL
2x2mm² pads
Mechanical frame
10 mm S.Steel
Holes 25x5 mm²
Mechanical design
Working pressure: at
Pads to FEE boards
IPN Orsay
IRFU

7. New anode frame inside the field cage
Prototype
New anode frame inside the field cage
AFTER board
MAYA geometry (drift)
High segmented anode (2x2 mm2, 576 ch)
Front-end board (AFTER-T2K)
Check of the 2D resolution (1 mm)
Drift with He+CF4 gas mixture (2011)
45°
Pad size effect
(2x2 vs 4x4 mm2)
Source 0°
Si strip detector
High density connector (67 ch)
22.6 mm
Pad geometry
rectangle vs triangle shape

8. Collaborations Actar specifications ACTAR 2p-TPC (CENBG)
Dynamic range 103
Multi-track capability yes
Spatial resoln 1 mm
Time resoln <10ns
Energy resoln 2%
Efficiency >90%
Count rates (trigger) <103
Beam count rates <106
Portability yes
ACTAR
Direct reactions (shell structure,
exotic nuclear system)
Resonant reactions
Giant resonances
Nuclear astrophysics
2p-TPC (CENBG)
Exotic decay at driplines
AT-TPC (NSCL-MSU)
Direct reaction
Nuclear Astrophysics
EOS
In discussion
RIKEN
EOS, structure studies
CERN-ISOLDE
MINOS (p,2p GSI, RIKEN
Fission-TPC (NFS/SPIRAL2)
R. Raabe, IN2P3 Scientific Concil
Synergies
Pad geometry, R&D design
Algorithms and event reconstruction
Calibration procedures (Laser)
Supervision and Control Command system
Gas handling system

9. General Electronics for TPC
Front-end electronics
Fast conversion
Calibration tools
HV, I, T control
Readout µTCA
Zero suppress
Time stamp
3-Level trigger
CPU
Event reconstruction
Event selection L3
ROOT analyses
GANIL
DAQ
See E. Delagnes’s talk
MSU
GANIL
ASAD
Event
builder
Run
control
Ext
preamp
ZAP
AGET
ADC
Readout
Process
NARVAL
Event
process
Storage
Gb transfer
CoBo
CENBG IRFU
ECC
Config
manager
Clock distrib
Trigger
L0, L2
Inspection box
time alignment
(Riken ?)
Spy
box
MUTANT
Process L1
SLOW
CONTROL
Data
base
Time reference
(GSI Butis)
Clock
provider
BEM
IRFU
See S. Anvar’s talk

10. Asic AGET architecture
12-bit ADC
25MHz
[ADS6422]
Serial Interface
Mode CK
In Test
CSA;CR;SCAin;DISCRIin(N°1)
Asic “Spy” Mode
Readout
SCA MANAGER
SLOW CONTROL
W / R
TEST
Power on
Reset
AGET
512 cells
SCA
FILTER
tpeak
CSA
1 channel
x64in
ADC
Charge range
DAC
Discri
inhibit
BUFFER
x68
Hit register
Σ 64 discri.
SCAwrite
Trigger pulse
64 analog channels with Sampling Capacitor Array
Preamp (4 ranges 120 fC, 240 fC, 1 pC, 10 pC)
Shaping (50ns – 1µs)
Sampling (512 cells)
Self-triggering
Active level of the analog sum (64 ch)
Time over threshold vs fixed width
Selective readout: hit channels [read & write]
Special SCA mode for decay studies
Slow Control
Gain, Shaping
Readout mode (nb cells)
Test mode
ch/ch (calibration)
all ch (test)
Spy mode (1 ch)

11. Additional Signal Processing
GET architecture
ASAD
AGET
ADC
TPC
Offline Analysis
COBO
L2 trig
Readout
Clock
µTCA
COBO
ASAD Readout
(Zero Suppress)
ASAD Readout
(Zero Suppress) L1
Mult
BEM
MEMORY
Signal Processing
MEMORY
Additional Signal Processing
MUTANT
Network Transfer
Network Transfer
Trigger
L0 Trig
External
Systems
GET Network Switch
10Gb Ethernet
Global Network
Computer Farm
Nb of ch
Rate in MB/s
Data Server
AGET + ADC ( 64)
AsAd: 4x AGET ( 256)
CoBo: 4x AsAd (1024)
µTCA
10x CoBo + Mutant (10240)
Up to 3 crates (30720)
AsAd out
CoBo in
CoBo out
µTCA
See S. Anvar’s talk
12% hit ch, 1kHz

12. Integration, Beam test validation GANIL µTCA standard evaluation
GET Time Table
ANR Funding (530 k€)
AGET
Design
Serie V2
Design
Build
150 chips V1
Test bench
Test bench
AsAd
Hardware design
Build
2x V1
2x V1b
Pre serie V2
Control, pulser
Power supply
Test bench firmware
Integration
Beam test
MSU
CoBo
Firmware
Test
Integration, Beam test validation GANIL
Source test
GANIL
ML507 toolkit
Proto
Test
Pre serie
Hardware design V1 V2
MUTANT
µTCA standard evaluation
Pre serie
Design
Proto, Tests V1 V2
Software
ECC, firmware
DB, GUI, Interfaces
Run Control
(2010) Specifications
Electromechanics design
Prototype µMegas-bulk Pads 2x2mm2
(2012) Test prototype
Building phase