G.Poggi – EURORIB08 – June 2008 FAZIA Collaboration: recent advances and perspectives R&D Phase I of FAZIA and optimizing Z and A identification by means of Pulse Shape in Silicon: Basic detection module: Si-Si-CsI (non-standard) Charge and current preamplifier (PACI) Fully digital electronics for Energy, Pulse Shape and Timing has been developed Pulse Shape and Silicon material: importance of controlling channeling and doping uniformity First prototypes tested in-beam Pulse Shape: what are the thresholds (E, Z and A)? Pulse Shape + ToF (SPIRAL2 PP + ….) Pulse Shape for low energy hydrogen and helium isotopes FAZIA Phase II dedicated to implement results of Phase I: Prototype Array (a small scale version of FAZIA) New Front End Electronics R&D Phase I of FAZIA and optimizing Z and A identification by means of Pulse Shape in Silicon: Basic detection module: Si-Si-CsI (non-standard) Charge and current preamplifier (PACI) Fully digital electronics for Energy, Pulse Shape and Timing has been developed Pulse Shape and Silicon material: importance of controlling channeling and doping uniformity First prototypes tested in-beam Pulse Shape: what are the thresholds (E, Z and A)? Pulse Shape + ToF (SPIRAL2 PP + ….) Pulse Shape for low energy hydrogen and helium isotopes FAZIA Phase II dedicated to implement results of Phase I: Prototype Array (a small scale version of FAZIA) New Front End Electronics In this talk: Not discussed, only reminded Discussed Briefly addressed and commented

The FAZIA (Four Pi Z and A Identification Array) initiative was formalized in Members are from France, Italy, Poland, Spain, Rumania (+Canada, India and US). The goal of the present Phase I: studying and testing new solutions, checking if possible to make a step forward toward the “ideal” detector array for Dynamics and Thermodynamics of heavy-ion collisions at Fermi energies and below The FAZIA (Four Pi Z and A Identification Array) initiative was formalized in Members are from France, Italy, Poland, Spain, Rumania (+Canada, India and US). The goal of the present Phase I: studying and testing new solutions, checking if possible to make a step forward toward the “ideal” detector array for Dynamics and Thermodynamics of heavy-ion collisions at Fermi energies and below The FAZIA Initiative FAZIA PHASE I: Working Groups 1.Modeling current signals and Pulse Shape Analysis in Silicon (L.Bardelli) 2.Physics cases (G.Verde) 3.Front End Electronics (P.Edelbruck) 4.Acquisition (A.Ordine) 5.CsI(Tl) crystals (M.Parlog) 6.Single Chip Telescope (G.P.) 7.Design, Detector, Integration and Calibration (M.Bruno) 8.Web site (O.Lopez) FAZIA PHASE I: Working Groups 1.Modeling current signals and Pulse Shape Analysis in Silicon (L.Bardelli) 2.Physics cases (G.Verde) 3.Front End Electronics (P.Edelbruck) 4.Acquisition (A.Ordine) 5.CsI(Tl) crystals (M.Parlog) 6.Single Chip Telescope (G.P.) 7.Design, Detector, Integration and Calibration (M.Bruno) 8.Web site (O.Lopez) CsI(Tl) H.I. ΔE1ΔE2 Si ? 300μm 500 / 700μm mm G.Poggi – EURORIB08 – June 2008

B C N O Beyond  E-E: Z and A Identification with Pulse Shape Energy vs rise-time of charge signals permits good Z identification of stopped particles (further identification criteria under study) A threshold exists for Z identification, for small particle penetration (a few tens of μm) Evidences exist that isotope separation (A identification) is possible above a certain penetration. Why Pulse Shape in Silicon is possible? Stopped particles with the same energy and different Z (and A) show charge/current signals having unlike time evolution because ranges and plasma erosion times differ Better identification for reverse-mount Silicon Why Pulse Shape in Silicon is possible? Stopped particles with the same energy and different Z (and A) show charge/current signals having unlike time evolution because ranges and plasma erosion times differ Better identification for reverse-mount Silicon First fully digital implementation of PSA in Silicon: L.Bardelli et al: NP A746 (2004) 272 G.Poggi – EURORIB08 – June 2008

Channeling and doping non -uniformity in Si for PSA G.Poggi – EURORIB08 – June 2008 Only very small scale implementation of high- quality PSA are reported in the literature (see Mutterer et al IEEE TNS 47 (2000) 756 ) ns Current [a.u] MeV Elastic scattering on Au ~100 mm 2 Silicon

Channeling and doping non -uniformity in Si for PSA Basing on an older work ( G.P. et al. NIM B119 (1996) 375) on channeling effects on stopped h.i., we suspected that channeling (and Silicon doping non-uniformity) was originating these instabilities. Could this also explain overall irreproducibility of PSA quality observed in the past? Basing on an older work ( G.P. et al. NIM B119 (1996) 375) on channeling effects on stopped h.i., we suspected that channeling (and Silicon doping non-uniformity) was originating these instabilities. Could this also explain overall irreproducibility of PSA quality observed in the past? G.Poggi – EURORIB08 – June 2008 Only very small scale implementation of high- quality PSA are reported in the literature (see Mutterer et al IEEE TNS 47 (2000) 756 ) Early FAZIA tests of our DPSA in Silicon with mono-energetic heavy-ions showed fluctuations in current and charge signal shape (also somewhat irreproducible) The key experiment: collimated Silicon detectors mounted on a remote-controlled precision goniometer. Signal behavior as a function of the impinging ion direction with respect to crystal axes. Both and silicon detectors have been studied The key experiment: collimated Silicon detectors mounted on a remote-controlled precision goniometer. Signal behavior as a function of the impinging ion direction with respect to crystal axes. Both and silicon detectors have been studied ns Current [a.u] MeV Elastic scattering on Au

Signal Risetime and Channeling in and Silicon Our findings for “Channeled” or “random-entering” stopped ions Channeled ions: strongly fluctuating rise-time due to… enhanced variations of range and plasma erosion time for directions close to crystal channels, which are basically… Our findings for “Channeled” or “random-entering” stopped ions Channeled ions: strongly fluctuating rise-time due to… enhanced variations of range and plasma erosion time for directions close to crystal channels, which are basically… G.Poggi – EURORIB08 – June 2008 “Channeled” ns MeV

Signal Risetime and Channeling in and Silicon G.Poggi – EURORIB08 – June 2008 If detectors subtend ~1° and are mounted in the usual way, most ions may experience abnormal fluctuations, given the large channeling probability (ψ ½ = 0.5°-1°) Channeling in Silicon is observed for front and rear injection If detectors subtend ~1° and are mounted in the usual way, most ions may experience abnormal fluctuations, given the large channeling probability (ψ ½ = 0.5°-1°) Channeling in Silicon is observed for front and rear injection “Channeled” ns MeV “Random” ns MeV Risetime-fluctuations vs gonio-angles Si Fluctuation increases For Silicon: typically 7° off-axis Our findings for “Channeled” or “random-entering” stopped ions Channeled ions: strongly fluctuating rise-time due to… enhanced variations of range and plasma erosion time for directions close to crystal channels, which are basically… … absent for random directions L.Bardelli et al; submitted to NIMA Our findings for “Channeled” or “random-entering” stopped ions Channeled ions: strongly fluctuating rise-time due to… enhanced variations of range and plasma erosion time for directions close to crystal channels, which are basically… … absent for random directions L.Bardelli et al; submitted to NIMA

Signal Risetime and Channeling in and Silicon The mandatory recipe for good Pulse Shape Analysis: USE PURPOSELY ORIENTED SILICON DETECTORS for ALWAYS MAINTAINING RANDOM INCIDENCE! We have ordered indeed special-cut nTD wafers The mandatory recipe for good Pulse Shape Analysis: USE PURPOSELY ORIENTED SILICON DETECTORS for ALWAYS MAINTAINING RANDOM INCIDENCE! We have ordered indeed special-cut nTD wafers MeV Silicon Current [a.u] “Channeled” ns “Random” ns Irreproducibility: minor geometry variations of the setup change the fraction of channeled ions Unfortunately this does not explain everything… The Silicon doping uniformity must also be controlled up to an unprecedented level This information is basically not available from (detector/wafer) manufacturers G.Poggi – EURORIB08 – June 2008 L.Bardelli et al: submitted to NIMA

Fixed impact point Various bias voltage Fixed impact point Various bias voltage Over depletion Full bias Slightly under-bias T_rise Resistivity measurements (doping uniformity) in Silicon A newly developed procedure to map Silicon resistivity, based on Transient Current Technique has been systematically applied to our detectors Reverse-mount Silicon det. Various applied voltages: from under- to over bias Narrow UV laser pulse (ns) R Si detector G.Poggi – EURORIB08 – June 2008

Fixed impact point Various bias voltage Fixed impact point Various bias voltage Over depletion Full bias Slightly under-bias T_rise Resistivity measurements (doping uniformity) in Silicon Reverse-mount Silicon det. Various applied voltages: from under- to over bias Narrow UV laser pulse (ns) R Si detector G.Poggi – EURORIB08 – June 2008 A typical detector: ~9% non-uniformity with striations (mm -1 spatial frequency) A newly developed procedure to map Silicon resistivity, based on Transient Current Technique has been systematically applied to our detectors

Fixed impact point Various bias voltage Fixed impact point Various bias voltage Over depletion Full bias Slightly under-bias T_rise Resistivity measurements (doping uniformity) in Silicon Reverse-mount Silicon det. Various applied voltages: from under- to over bias Narrow UV laser pulse (ns) R Si detector G.Poggi – EURORIB08 – June 2008 A non typical, very good detector: ~1% non- uniformity with undetectable striations A newly developed procedure to map Silicon resistivity, based on Transient Current Technique has been systematically applied to our detectors Memento: good resistivity uniformity  good uniformity of electric field  position independence of timing

PSA test run with full control of channeling and resistivity 32 S MeV (LNL, December 2007) PSA test run with full control of channeling and resistivity 32 S MeV (LNL, December 2007) Si-Si, Si-CsI and “Single Chip Tel” have been used. All Silicons were characterized for uniformity, were un-collimated and have the “FAZIA” dimensions(400mm 2 ) PACI preamps A fully digital FEE for charge and current PSA has been developed (Orsay+Florence) for Phase I Si-Si, Si-CsI and “Single Chip Tel” have been used. All Silicons were characterized for uniformity, were un-collimated and have the “FAZIA” dimensions(400mm 2 ) PACI preamps A fully digital FEE for charge and current PSA has been developed (Orsay+Florence) for Phase I Channeling control for the experiment: Detectors made of random-cut Silicon were not yet available All detectors are cut 0° off axis Channeling--random control obtained by proper 7° detector tilting (simple mechanical adjustment permits to switch from unwanted channeling to desired “random” orientations) Channeling control for the experiment: Detectors made of random-cut Silicon were not yet available All detectors are cut 0° off axis Channeling--random control obtained by proper 7° detector tilting (simple mechanical adjustment permits to switch from unwanted channeling to desired “random” orientations) G.Poggi – EURORIB08 – June 2008 Channeled ions Random entering ionsQuasi-random entering ions Wrong detector mounting causes some residual planar channeling

32 S MeV (December 2007) Channel or not to channel? 32 S MeV (December 2007) Channel or not to channel? 300 μ500 μ 32 S MeV Pulser Very uniform 500μm Silicon Standard mounting, i.e. perpendicular ion incidence is expected to induce channeling Satisfactory Z identification over the full examined range Very uniform 500μm Silicon Standard mounting, i.e. perpendicular ion incidence is expected to induce channeling Satisfactory Z identification over the full examined range Normally impinging ions DIGITAL PULSE SHAPE on 500μ Silicon Full scale: ~1.5 GeV Be B C N O F Ne Na Are channeling effects really important? G.Poggi – EURORIB08 – June 2008

32 S MeV Pulser 300 μ500 μ Very uniform 500μm Silicon Channeling was partly spoiling overall identification Random: 7° tilt angle Mass identification clearly shows up! Very uniform 500μm Silicon Channeling was partly spoiling overall identification Random: 7° tilt angle Mass identification clearly shows up! Random impinging ions DIGITAL PULSE SHAPE on 500μ Silicon Full scale: ~1.5 GeV Be B C N O F Ne Na Yes, they are! Channeling was spoiling mass identification 32 S MeV (December 2007) Channel or not to channel? 32 S MeV (December 2007) Channel or not to channel? G.Poggi – EURORIB08 – June 2008

32 S MeV 500 μ Normally impinging ions DIGITAL PULSE SHAPE on 500μ Silicon Full scale: ~ 4 GeV Be B C N O F Ne Na Mg Al Si P S Cl Ar K 32 S MeV (December 2007) Channel or not to channel? 32 S MeV (December 2007) Channel or not to channel? Very uniform 500μm Silicon Standard mounting, i.e. perpendicular ion incidence Satisfactory Z identification over the full examined range Note the very high energy range Very uniform 500μm Silicon Standard mounting, i.e. perpendicular ion incidence Satisfactory Z identification over the full examined range Note the very high energy range G.Poggi – EURORIB08 – June 2008 Unity counts removed

500 μ Random impinging ions DIGITAL PULSE SHAPE on 500μ Silicon Full scale: ~ 4 GeV Unity counts removed 32 S MeV Be B C N O F Ne Na Mg Al Si P S Cl Ar K 32 S MeV (December 2007) Channel or not to channel? 32 S MeV (December 2007) Channel or not to channel? Very uniform 500μm Silicon Channeling was partly spoiling identification “Random” mounting Very uniform 500μm Silicon Channeling was partly spoiling identification “Random” mounting G.Poggi – EURORIB08 – June 2008

DIGITAL PULSE SHAPE on 500μm and 300μm Silicons with similar field and different doping non-uniformities 300μm: ~ 4 GeV full scale 500μm: ~ 4 GeV full scale 32 S MeV (December 2007): doping uniformity G.Poggi – EURORIB08 – June 2008 Quasi-random, but non-uniform Silicon shows reasonable Z resolution Quasi-random, very uniform Silicon shows clean Z and partial A resolution 250V on 500μm 1% non-uniformity Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca 500 μ 140V on 300μm 9.4% non-uniformity Be B C N O F Ne Na Mg Al Si P S Cl? Ar? 300 μ

32 S MeV (December 2007): doping uniformity G.Poggi – EURORIB08 – June V on 300μm 9.4% non-uniformity Be B C N O F Ne Na Mg Al Si P S Cl? Ar? 140V on 300μm 9.4% non-uniformity C N O F Ne Na Mg Al 300 μ 500 μ Quasi-random, but non-uniform Silicon shows reasonable Z resolution Quasi-random, very uniform Silicon shows clean Z and partial A resolution DIGITAL PULSE SHAPE on 500μm and 300μm Silicons with similar field and different doping non-uniformities 300μm: ~ 4 GeV full scale 500μm: ~ 4 GeV full scale 250V on 500μm 1% non-uniformity Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca 500 μ C N O F Ne Na Mg Al 250V on 500μm 1% non-uniformity

Preliminary conclusions: with uniformity-controlled and “random”-oriented Silicon detectors, Digital PSA developed in FAZIA permits unity charge resolution at least up to Z ~ 30 (probably >50), with energy thresholds of about 3MeV/n for C and 4MeV/n for Ne (about μm of Silicon) DPSA gives mass resolution for Z 100μm (?) of Silicon ToF might significantly extend this mass resolution Preliminary conclusions: with uniformity-controlled and “random”-oriented Silicon detectors, Digital PSA developed in FAZIA permits unity charge resolution at least up to Z ~ 30 (probably >50), with energy thresholds of about 3MeV/n for C and 4MeV/n for Ne (about μm of Silicon) DPSA gives mass resolution for Z 100μm (?) of Silicon ToF might significantly extend this mass resolution FAZIA Phase I: Digital Pulse Shape on Silicon G.Poggi – EURORIB08 – June Ni 60 Ni Frankly, we are not unhappy about these preliminary results…

Best algorithms for DPSA are under study within FAZIA WG1 (S.Barlini et al: in preparation) Adding ToF to current or charge risetime for extending mass resolution of low energy stopped particles Trying to get ToF even with non- optimal time structure of the pulsed beam (supported by Spiral2 PP) Addressing Digital Pulse Shape for Silicon strip and Z = 1,2 ions (supported by Spiral2 PP) Future experiments: LNL, LNS, GANIL… Best algorithms for DPSA are under study within FAZIA WG1 (S.Barlini et al: in preparation) Adding ToF to current or charge risetime for extending mass resolution of low energy stopped particles Trying to get ToF even with non- optimal time structure of the pulsed beam (supported by Spiral2 PP) Addressing Digital Pulse Shape for Silicon strip and Z = 1,2 ions (supported by Spiral2 PP) Future experiments: LNL, LNS, GANIL… FAZIA Phase I: next steps G.Poggi – EURORIB08 – June rd vs 2 nd moment of current signals Y axis: measured energy X axis: measured rise-time + simulated ToF over 1.1m and 0.5 ns FWHM (smoothly merged) Y axis: measured energy X axis: measured rise-time + simulated ToF over 1.1m and 0.5 ns FWHM (smoothly merged) Exp+Sim

~10 4 telescopes Phase II (from 2008 till 2012): Prototype Array (20-30 modules) to couple with existing arrays and do Physics out of it Implement the solutions devised and tested on Phase I adopt electronic and mechanical solutions as close as possible to the final 4π configuration (e.g. neutron detection feasibility and transportability) Phase III (from 2012 on): Build a Demonstrator, covering a significant fraction of 4π, e.g C2+C1 Phase II (from 2008 till 2012): Prototype Array (20-30 modules) to couple with existing arrays and do Physics out of it Implement the solutions devised and tested on Phase I adopt electronic and mechanical solutions as close as possible to the final 4π configuration (e.g. neutron detection feasibility and transportability) Phase III (from 2012 on): Build a Demonstrator, covering a significant fraction of 4π, e.g C2+C1 FAZIA R&D Phase II (and Phase III) A possible final FAZIA Array (JM Gautier-LPC) x 8 G.Poggi – EURORIB08 – June 2008 C1C2 C3 C4

FEE structure under vacuum to simplify connections (the very issue under study: power removal) Bidirectional fast (2.2 Gb/s) fiber optics guarantees synchronous trigger info transmission and transfer of samples (data). The last level provides trigger construction / validation / event labeling + sample dispatching to DAQ Fast FPGA-based elaboration and protocol management FEE structure under vacuum to simplify connections (the very issue under study: power removal) Bidirectional fast (2.2 Gb/s) fiber optics guarantees synchronous trigger info transmission and transfer of samples (data). The last level provides trigger construction / validation / event labeling + sample dispatching to DAQ Fast FPGA-based elaboration and protocol management FAZIA R&D Phase II: the FEE G.Poggi – EURORIB08 – June First Level FEE Unit Vacuum Air Trigger and data collector + dispatcher Trigger info and samples 2.2 Gb/s Trigger validation and slow control 2.2 Gb/s Ethernet DAQTrigger Box Trigger info Trigger validation and event labeling..64..Samples Trigger decision (400 ns) Data transmission to PC farm Trigger/samples separation and trigger elaboration Fast and slow Energy shaping Local digital trigger generation (100 ns)+ second level decision (over in 2-3 μs) + data sending (asynchronous) Fast and slow Energy shaping Local digital trigger generation (100 ns)+ second level decision (over in 2-3 μs) + data sending (asynchronous)

The FAZIA organization FAZIA Project Management Board: B.Borderie, R. Borcea, R.Bougault, A.Chbihi, F.Gramegna, T.Kozik, I.Martel Bravo, E.Rosato, G.P. and R.Roy Sc. Coordinators: G.P. and R.Bougault Tech. Coordinator: P.Edelbruck FAZIA Project Management Board: B.Borderie, R. Borcea, R.Bougault, A.Chbihi, F.Gramegna, T.Kozik, I.Martel Bravo, E.Rosato, G.P. and R.Roy Sc. Coordinators: G.P. and R.Bougault Tech. Coordinator: P.Edelbruck FAZIA Working Groups 1.Modeling current signals and Pulse Shape Analysis (L.Bardelli) 2.Physics cases (G.Verde) 3.Front End Electronics (P.Edelbruck) 4.Acquisition (A.Ordine) 5.CsI(Tl) crystals (M.Parlog) 6.Single Chip Telescope (G.P.) 7.Design, Detector, Integration and Calibration (M.Bruno) 8.Web site (O.Lopez) FAZIA Working Groups 1.Modeling current signals and Pulse Shape Analysis (L.Bardelli) 2.Physics cases (G.Verde) 3.Front End Electronics (P.Edelbruck) 4.Acquisition (A.Ordine) 5.CsI(Tl) crystals (M.Parlog) 6.Single Chip Telescope (G.P.) 7.Design, Detector, Integration and Calibration (M.Bruno) 8.Web site (O.Lopez) A dedicated Discussion Group is studying the Physics requirements for the Trigger (M.F.Rivet and A.Olmi) to implement with our electronic engineers Two more slides on “synergies” G.Poggi – EURORIB08 – June 2008

Questions fitting very well with our Topic Is channeling an issue only for PSA-based identification? How about channeling and more standard identification approaches? Significant effects are expected in  E-E: channeling may change  E, as many of us have seen when punching-through elastic scattering is measured This effect is less clearly appreciated in other cases, but still present Synergies in instrumentation Elastic scattering in 93 Nb MeV/n E EE

32 S MeV 300 μ500 μ Normally impinging ions Digital  E-E μ Silicon (reverse field) Full scale  E: ~4GeV Full scale E: ~1.5 GeV Be B C N O F Ne Na Li G.Poggi – EURORIB08 – June S MeV (December 2007) Telescope mounted for standard normal incidence Why so-so resolution? Never happened to you? Telescope mounted for standard normal incidence Why so-so resolution? Never happened to you? Try a little, proper detector tilting … Unity counts removed

32 S MeV 300 μ500 μ Random impinging ions Digital  E-E μ Silicon (reverse mount) Full scale  E: ~4GeV Full scale E: ~1.5 GeV Telescope mounted for 7° incidence (Quasi-random configuration) Be B C N O F Ne Na Li 32 S MeV (December 2007) Beneficial effects of random incidence for standard  E-E identification 32 S MeV (December 2007) Beneficial effects of random incidence for standard  E-E identification G.Poggi – EURORIB08 – June 2008 … say channeling “goodbye” We believe that one should keep this result in mind for any future  E(Si)-E implementation. Do not overlook the old recommendation of 7° off-axis cut and double check what you buy. Thanks to the audience Unity counts removed