G.Poggi – LEA-LNS – October 2008 Recent results of the FAZIA Collaboration R&D Phase I of FAZIA consists in 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 crystal orientation and doping uniformity First prototypes: in-beam tested performances Pulse Shape: what are the thresholds (E, Z and A)? Pulse Shape + ToF (SPIRAL2 PP + ….) 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 consists in 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 crystal orientation and doping uniformity First prototypes: in-beam tested performances Pulse Shape: what are the thresholds (E, Z and A)? Pulse Shape + ToF (SPIRAL2 PP + ….) 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.Semiconductor Detectors (same as WG1) 6.CsI(Tl) crystals (M.Parlog) 7.Single Chip Telescope (G.P.) 8.Design, Detector, Integration and Calibration (M.Bruno) 9.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.Semiconductor Detectors (same as WG1) 6.CsI(Tl) crystals (M.Parlog) 7.Single Chip Telescope (G.P.) 8.Design, Detector, Integration and Calibration (M.Bruno) 9.Web site (O.Lopez) CsI(Tl) H.I. ΔE1ΔE2 Si ? 300μm 500 / 700μm mm G.Poggi – LEA-LNS – October 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 – LEA-LNS – October 2008

“Channeling” and doping non -uniformity in Si for PSA ns Current [a.u] MeV Elastic scattering on Au ~100 mm 2 Silicon G.Poggi – LEA-LNS – October 2008 Only very small scale implementation of high-quality PSA are reported in the literature (Mutterer et al IEEE TNS 47 (2000) 756 ) Chimera is a large scale implementation of analogue pulse shape with front-mount detectors Only very small scale implementation of high-quality PSA are reported in the literature (Mutterer et al IEEE TNS 47 (2000) 756 ) Chimera is a large scale implementation of analogue pulse shape with front-mount detectors

“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 crystal orientation (and 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 crystal orientation (and doping non-uniformity) was originating these instabilities. Could this also explain overall irreproducibility of PSA quality observed in the past? Only very small scale implementation of high-quality PSA are reported in the literature (Mutterer et al IEEE TNS 47 (2000) 756 ) Chimera is a large scale implementation of analogue pulse shape with front-mount detectors Only very small scale implementation of high-quality PSA are reported in the literature (Mutterer et al IEEE TNS 47 (2000) 756 ) Chimera is a large scale implementation of analogue pulse shape with front-mount detectors Early FAZIA tests of our DPSA in Silicon with mono-energetic heavy-ions showed fluctuations in current and charge signal shape (also partly 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 G.Poggi – LEA-LNS – October 2008

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 axes, 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 axes, which are basically… “Channeled” ns MeV G.Poggi – LEA-LNS – October 2008

Signal Risetime and “Channeling” in and Silicon 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 axes, which are basically… … absent for random directions 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 axes, which are basically… … absent for random directions G.Poggi – LEA-LNS – October 2008

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 L.Bardelli et al: under tedious refereeing procedure on NIMA G.Poggi – LEA-LNS – October 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 A newly developed procedure to map Silicon resistivity, based on Transient Current Technique, has been developed and 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 – LEA-LNS – October 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 A newly developed procedure to map Silicon resistivity, based on Transient Current Technique has been systematically applied to our detectors G.Poggi – LEA-LNS – October 2008 A typical detector: ~9% non-uniformity with striations (mm -1 spatial frequency)

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 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-independent signal shape  best available PSA G.Poggi – LEA-LNS – October 2008

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) Channeled ions Random entering ionsQuasi-random entering ions Wrong detector mounting causes some residual planar channeling G.Poggi – LEA-LNS – October 2008

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 crystal orientation effects really important? G.Poggi – LEA-LNS – October 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 the available mass identification 32 S MeV (December 2007) Channel or not to channel? 32 S MeV (December 2007) Channel or not to channel? G.Poggi – LEA-LNS – October 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 Unity counts removed G.Poggi – LEA-LNS – October 2008

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 – LEA-LNS – October 2008

300 μ500 μ Normally impinging ions Digital  E-E μ Silicon (reverse mount) Full scale  E: ~4GeV Full scale E: ~1.5 GeV 32 S MeV (December 2007) A two-slide digression: how about “channeling” and the  E-E approach? 32 S MeV (December 2007) A two-slide digression: how about “channeling” and the  E-E approach? Telescope mounted for standard normal incidence Why so-so resolution? Is it due to the reverse mount configuration as some claim? Telescope mounted for standard normal incidence Why so-so resolution? Is it due to the reverse mount configuration as some claim? 32 S MeV Be B C N O F Ne Na Li Unity counts removed G.Poggi – LEA-LNS – October 2008 Try a little, proper detector tilting …

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 Improper crystal orientation was the culprit. With “random” orientation the poor resolution is gone Unity counts removed G.Poggi – LEA-LNS – October 2008 Back to Pulse Shape Analysis

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 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 G.Poggi – LEA-LNS – October 2008

32 S MeV (December 2007): doping uniformity 140V 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 G.Poggi – LEA-LNS – October 2008

Simulation: 1.3% non-uniformity, electronic noise and longitudinal straggling Simulation: perfect uniformity, electronic noise and longitudinal straggling included Simulation: %5 non uniformity, electronic noise and longitudinal straggling 32 S MeV (December 2007): doping uniformity G.Poggi – LEA-LNS – October 2008 What are the limits imposed by doping non-uniformity? The answer may come from simulations, based on calculations by W.Seibt et al (NIM 113 (1973) 317), introducing a local variation of depletion voltage as a function of particle impact point (S.Carboni, Master Thesis, in preparation) What are the limits imposed by doping non-uniformity? The answer may come from simulations, based on calculations by W.Seibt et al (NIM 113 (1973) 317), introducing a local variation of depletion voltage as a function of particle impact point (S.Carboni, Master Thesis, in preparation) Simulation is basically able to reproduce the data: doping non- uniformity must be around 1% if mass resolution is aimed at (data is now only available for A=10-20) Experiment: measured 1.3% non-uniformity Be B C N O

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< (conclusion also based on short- run results with 58,60 Ni) particles, when ranges are <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< (conclusion also based on short- run results with 58,60 Ni) particles, when ranges are <100μm (?) of Silicon ToF might significantly extend this mass resolution FAZIA Phase I: Digital Pulse Shape on Silicon 58 Ni 60 Ni These preliminary results look promising… G.Poggi – LEA-LNS – October 2008

Best algorithms for DPSA are under study within FAZIA WG1: FAZIA Phase I: next steps 3 rd vs 2 nd moment of current signals S.Barlini et al: in preparation G.Poggi – LEA-LNS – October 2008 E vs (E and I max ) linear combination Improved Z and A discrimination E vs (E and I max ) linear combination Improved Z and A discrimination Be B C N O F Li

Best algorithms for DPSA are under study within FAZIA WG1: 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: LNS and GANIL… Best algorithms for DPSA are under study within FAZIA WG1: 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: LNS and GANIL… FAZIA Phase I: next steps 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 G.Poggi – LEA-LNS – October 2008

~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 C1C2 C3 C4 G.Poggi – LEA-LNS – October 2008

FEE structure under vacuum to simplify connections (the very issue under study: power removal) Bidirectional fast (at least 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 (at least 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 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) G.Poggi – LEA-LNS – October 2008

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.Semiconductor Det. (with WG1) 6.CsI(Tl) crystals (M.Parlog) 7.Single Chip Telescope (G.P.) 8.Design, Detector, Integration and Calibration (M.Bruno) 9.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.Semiconductor Det. (with WG1) 6.CsI(Tl) crystals (M.Parlog) 7.Single Chip Telescope (G.P.) 8.Design, Detector, Integration and Calibration (M.Bruno) 9.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 G.Poggi – LEA-LNS – October 2008 We are still shocked and deeply sad: our friend and precious colleague Jean Marc Gautier died few days ago