1. The FAZIA modules: recent results and possible couplings with gas detectors
S. Barlini for the FAZIA collaboration
GDS Workshop, January

2. (FEW) WORDS ABOUT FAZIA……. Some of the physic case of interest:
International collaboration born to design and build a new detector for charged particles optimized for heavy ions collisions at the Fermi energies.
Some of the physic case of interest:
Isospin diffusion/equilibration
Nuclear Equation of state
Features of low density regions
(peripheral reactions, neck zone, skin effects)
Cluster formation
n/p and mirror nuclei ratios
… and more:
e.g. Dynamical dipole and pygmy resonances (gamma probes)
INDRA+FAZIA AT GANIL
FIRST “REAL” EXPERIMENTS AT LNS
Future
Detector R&D
Present time
Finished!
S.Barlini et al., PRC87(2013), 54607
S.Piantelli et al., PRC88(2013), 64607

3. (FEW) WORDS ABOUT FAZIA…….
FAZIA is a new array for charged particles based on a three stages telescope 2x2 cm using Si (300 µm) + Si (500 µm) + CsI (Tl) (10 cm) with a fully digital low noise electronic.
"Random" cut of the Silicon wafers tilted with respect to the major crystal direction
Selection of Silicon detectors with good planarity and parallelism of front and rear sides (high thickness uniformity)
An Aluminum layer of about 30 nm on both sides of detectors: less sheet resistance to preserve good timing properties
Construction
Careful control of the constancy of the electric field inside the Si as a function of time: monitoring of reverse current and correction of the voltage drop across the bias resistor
Reverse mounting configuration of Silicon detectors: the particles enter from the low-field side.
Operation mode
Usage of nTD Silicon detectors with good dopant homogeneity (1-3%)
This should be checked!!
S.Barlini at al., NIMA600 (2009), 644
L.Bardelli et al., NIMA605 (2009), 353
L.Bardelli et al., NIMA654 (2011), 272
S.Carboni et al., NIMA664 (2012), 251
G.Pasquali et al., EPJ A48, (2012), 158
N.Le Neindre et al., NIMA701(2013), 145
S.Barlini et al., NIMA707(2013), 89
R.Bougault et al., EPJA50 (2014), 1
G.Pasquali et al, EPJA (2014), 86
G.Pastore et al,, NIMA(2017) in press
Main “Technical” results published on

4. (BRIEF) OVERVIEW OF THE FAZIA ELECTRONICS…….
14 bit 250 MHz
x16 F P G A . PA
14 bit 100 MHz
Si1
14 bit 250 MHz
4 GeV f.s.
d/dt
More details in J. of Instr. Vol.11 (2016), 01064
and in S.Valdré talk.
Current . PA
14 bit 100 MHz
Si2
4 GeV f.s.
14 bit 250 MHz
d/dt
Current PA
14 bit 100 MHz
CsI(Tl)
Embedded FEE Logics
FEE CARD
Preamplifier stage
CsI
Local trigger
Memories & buffers
Input/output
Telescope B
Si2
Si1
CsI
Embedded FEE functions
Si2
Pulser to all channels
Generation, Si-HV monitoring
Telescope A
Si1
GDS Workshop, January 2017

5. (BRIEF) OVERVIEW OF THE FAZIA ELECTRONICS…….
HV card
INFN Naples
project
IPN Orsay
FEE connector
HV card
Block card
Silicon detector organized in “quartet”
1 block= 16 telescopes
Kapton to transmit the signal
Many detectors, many Kapton to be connected!!
Kapton bounding!
GDS Workshop, January 2017

6. (BRIEF) OVERVIEW OF THE FAZIA ELECTRONICS…….
Complexity inside, simplicity outside!
BLOCK BACK SIDE
2 optical fiber connectors
ONLY 3 I/O WAYS!!!
48V input
(power)
Local trigger
Cooling pipes
Global trigger
GDS Workshop, January 2017

7. WHAT WE OBTAIN USING FAZIA DETECTOR….
ΔE-E Method
G.Pastore et al., NIMA (2017) in press about PSA
G.Pastore, ISOFAZIA analysis, Ph.D Thesis Kr
GDS Workshop, January 2017

8. WHAT WE OBTAIN USING FAZIA DETECTOR….
ΔE-E Method
Z=17
Heavier ions punching-through
GDS Workshop, January 2017

9. WHAT WE OBTAIN USING FAZIA DETECTOR….
ΔE-E Method
PARTICLE IDENTIFICATION PLOT PI PI PI
GDS Workshop, January 2017

10. WHAT WE OBTAIN USING FAZIA DETECTOR….
ΔE-E Method
Similar results using Si2vs CsI detector
Z=18
GDS Workshop, January 2017

11. WHAT WE OBTAIN USING FAZIA DETECTOR….
ΔE-E Method
Z=12
GDS Workshop, January 2017

12. WHAT WE OBTAIN USING FAZIA DETECTOR….
ΔE-E Method
PARTICLE IDENTIFICATION PLOT PI PI
GDS Workshop, January 2017

13. WHAT WE OBTAIN USING FAZIA DETECTOR….
ΔE-E Method
The nuclide chart as detected in FAZIA first experiments
(adapted from J.Frankland, Spiral2 week, 2014)
GDS Workshop, January 2017

14. WHAT WE OBTAIN USING FAZIA DETECTOR….
PSA Method Be Li He
p,d,t
GDS Workshop, January 2017

15. WHAT WE OBTAIN USING FAZIA DETECTOR….
PSA Method
Kr line
Identification with only first layer
LCP
4He
3He
Z=1
GDS Workshop, January 2017

16. WHAT WE OBTAIN USING FAZIA DETECTOR….
PSA Method
ENERGY THRESHOLD FOR Z and A IDENTIFICATION
Lowering of thresh. using PSA
Identification with only first layer
Silicon detector with 1.3% FWHM doping homogeneity
GDS Workshop, January 2017

17. FOCUS: the effect of homogeneity on PSA
Similar electronic chain, different detector homogeneity
GDS Workshop, January 2017

18. FAZIA IN THE CONTEST OF THE NEW FACILITY FOR EXOTIC BEAMS….
Can we do better as identication threshold?
The use of silicon wafers with a better doping homogeneity can slightly improve the threshold
The use of under- depleted detector can increase the isotope separation, but not lower the threshold
SPES beam energy range
Under- depleted detector (G.Pasquali et al., EPJA50 (2014), 86)

19. FAZIA IN THE CONTEST OF THE NEW FACILITY FOR EXOTIC BEAMS….
Si1 (300 um) + Si2 (500um) + CsI(Tl) (10 cm)
SPES beam energy range
Using the “stabdard” FAZIA telescopes, there are threshold problems when we want to work with ISOL exotic beams (typically beam with no more than 10 AMeV)
Thinner silcon detector as first layer (20 um)
Gas detector instead of the first silicon
FAZIA as “ancillary” detector for products with enough energy
GDS Workshop, January 2017

20. FAZIA IN THE CONTEST OF THE NEW FACILITY FOR EXOTIC BEAMS….
Thinner silcon detector as first layer (20 um)
20 um
A.Kordyasz et al., EPJA(2015)51, 15
500um
CsI(Tl)
In nov.2016, a similar 20 um ion implanted epitaxial silicon detector has been mounted on the FAZIA mechanic and tested with success with alpha source
No isotopes separation
Absolutely no PSA
Energy threshold beetween 1 and 2MeV/u (Mn)
21m thick

21. FAZIA IN THE CONTEST OF THE NEW FACILITY FOR EXOTIC BEAMS….
Gas detector instead of first silicon layer
Gas first stage: lower threshold, but more complication (gas recirculation, windows to enclose the gas….). Of course is not a “new” solution (INDRA, RCo detectors in LNL)
M.Bruno et al., EPJA (2013) 49, 128
Example of “modern” apparatus with digital electronic
50 mbar, threshold around 1 MeV/u
GDS Workshop, January 2017

22. FAZIA IN THE CONTEST OF THE NEW FACILITY FOR EXOTIC BEAMS….
FAZIA as “ancillary” detector for products with enough energy
LOI for ACTIVE TARGET AT LNL
Each module of FAZIA is around 8x8 cm.
Electronic coupling with other detector can be obtained via standard GTS method (implemented in FAZIA Regional Board to be coupled with the INDRA detector in GANIL)
FAZIA can be used:
To cover some particular region where lighter and more energetic fragments are expected
To detect light particle outside an ACTIVE TARGET
FAZIA detector to have the best performance should be in vacuum. A careful design of the interface between ACTIVE TARGET and FAZIA is needed.
GDS Workshop, January 2017

23. CONCLUSION
FAZIA is a new apparatus for charged particles based on Si (300um)+Si (500 um)+ CsI(Tl) telescopes. The use of optimized silicon detectors and a low noise digital electronic inside the scattering chamber as near as possible to the detectors permits a very good performance in terms of ion identification using the ΔE-E technique or the PSA.
Some modifications in the design, as a thinner first silicon layer or the use of a gas layer as first stage of the detector, can be considered in order to lower the identification threshold to be ready for the new ISOL facility for exotic beam
The FAZIA electronic can be adapted for the less energetic ISOL exotic beam with some modification in the pre-amplifier gain in order to decrease the full range (4 GeV at the moment).
The FAZIA apparatus is modular and easy to mount and transport. In some physics cases, if the fragments have enough energy, can be used as ancillary detector.
GDS Workshop, January 2017