Recent results from the ISOFAZIA experiment

Transcription

1 Simone Valdré Grand Accélérateur National d Ions Lourds Recent results from the ISOFAZIA experiment Nusym 2017 GANIL, Maison d hôtes September 7 th, 2017

2 ISOFAZIA experiment at LNS Aim of this work Study of 80 Kr + 40,48 Ca reactions at 35 MeV/u Multifragmentation in central collisions Quasi-projectile dynamical fission Isospin transport effects in semi-peripheral collisions G. Pastore et al., Nuovo Cimento C 39, 383 (2016) G. Pastore, PhD Thesis (2017) 1/20

3 ISOFAZIA experiment at LNS Aim of this work Study of 80 Kr + 40,48 Ca reactions at 35 MeV/u Multifragmentation in central collisions Quasi-projectile dynamical fission Isospin transport effects in semi-peripheral collisions Outline Experimental apparatus: LNS G. Pastore et al., Nuovo Cimento C 39, 383 (2016) G. Pastore, PhD Thesis (2017) 1/20

4 ISOFAZIA experiment at LNS Aim of this work Study of 80 Kr + 40,48 Ca reactions at 35 MeV/u Multifragmentation in central collisions Quasi-projectile dynamical fission Isospin transport effects in semi-peripheral collisions Outline Experimental apparatus: LNS Isospin transport and models G. Pastore et al., Nuovo Cimento C 39, 383 (2016) G. Pastore, PhD Thesis (2017) 1/20

5 ISOFAZIA experiment at LNS Aim of this work Study of 80 Kr + 40,48 Ca reactions at 35 MeV/u Multifragmentation in central collisions Quasi-projectile dynamical fission Isospin transport effects in semi-peripheral collisions Outline Experimental apparatus: LNS Isospin transport and models Results and conclusions G. Pastore et al., Nuovo Cimento C 39, 383 (2016) G. Pastore, PhD Thesis (2017) 1/20

6 LNS The telescope stages µm reverse-mounted Si detector; µm reverse-mounted Si detector; 3 cm CsI(Tl) cristal read by a photodiode. To achieve the best possible energy resolution and A and Z identification Si detectors come from a ntd ingot cut at random angle to avoid channeling effects. 2/20

7 LNS The telescope stages µm reverse-mounted Si detector; µm reverse-mounted Si detector; 3 cm CsI(Tl) cristal read by a photodiode. To achieve the best possible energy resolution and A and Z identification Si detectors come from a ntd ingot cut at random angle to avoid channeling effects. 2/20

8 LNS The telescope stages µm reverse-mounted Si detector; µm reverse-mounted Si detector; 3 cm CsI(Tl) cristal read by a photodiode. To achieve the best possible energy resolution and A and Z identification Si detectors come from a ntd ingot cut at random angle to avoid channeling effects. 2/20

9 The FAZIA block FEE card 2 telescopes are connected to a FEE card. 3/20

10 The FAZIA block FEE card FEE card Back plane Half-bridge and power supply cards Block card 8 FEE cards are connected to a block card via a back plane. 3/20

11 The FAZIA block Block is mounted on a copper base in which water flows to provide cooling 3/20

12 The FAZIA block FEE card FEE card Back plane Half-bridge and power supply cards Block card 48 V DC power supply FEE card FEE card Back plane Half-bridge and power supply cards Block card Regional board to acquisition vacuum air up to 36 block cards are connected to a regional board via a full duplex 3 Gb/s optical link 3/20

13 FAZIA innovative features FAZIA implements compact electronics that permit to do on-line analysis just next the detectors minimization of signal distortion data reduction at the source 4/20

14 FAZIA innovative features FAZIA implements compact electronics that permit to do on-line analysis just next the detectors minimization of signal distortion data reduction at the source Modularity of the array FAZIA blocks can be arranged into many setups CENTRUM module for coupling with other apparatuses 4/20

15 FAZIA innovative features FAZIA implements compact electronics that permit to do on-line analysis just next the detectors minimization of signal distortion data reduction at the source Modularity of the array FAZIA blocks can be arranged into many setups CENTRUM module for coupling with other apparatuses Low identification thresholds thanks to PSA: charge identification from 2 MeV/u (for Z = 6) isotopic discrimination from 5 MeV/u (for Z = 6) 4/20

16 FAZIA innovative features FAZIA implements compact electronics that permit to do on-line analysis just next the detectors minimization of signal distortion data reduction at the source Modularity of the array FAZIA blocks can be arranged into many setups CENTRUM module for coupling with other apparatuses Low identification thresholds thanks to PSA: charge identification from 2 MeV/u (for Z = 6) isotopic discrimination from 5 MeV/u (for Z = 6) Despite its compact design, the FAZIA block has a good energy resolution and isotopic discrimination up to Z 25 4/20

17 ISOFAZIA setup block 0 80 Kr 35 MeV/u target cm 2.4 block 1 block 2 block 3 View from above 5/20

18 ISOFAZIA setup 5/20

19 ISOFAZIA data processing Acquisition Raw data 6/20

20 ISOFAZIA data processing Acquisition Raw data Calibration (kaliveda) Identified and calibrated products Analysis routine 6/20

21 Physics case Asymmetric nuclear matter Equation of State (asy EoS) Symmetry energy term depending on proton and neutron densities: E A (ρ, δ) = E A (ρ, 0) + E sym A (ρ)δ2 + O (δ 4) Isospin parameter δ = (ρ n ρ p ) ρ N Z A E sym behaviour is known only near ρ 0 7/20

22 Physics case Asymmetric nuclear matter Equation of State (asy EoS) Symmetry energy term depending on proton and neutron densities: E A (ρ, δ) = E A (ρ, 0) + E sym A (ρ)δ2 + O (δ 4) Isospin parameter δ = (ρ n ρ p ) ρ N Z A E sym behaviour is known only near ρ 0 7/20

23 Isospin transport Isospin diffusion Projectile and target isospins tend to equilibrate during interaction Isospin diffusion favoured by an asy-soft EoS parametrization 8/20

24 Isospin transport Isospin drift Neutrons tend to migrate toward low density regions (neck) Isospin drift favoured by an asy-stiff EoS parametrization 8/20

25 Isospin transport Isospin drift Neutrons tend to migrate toward low density regions (neck) Isospin drift favoured by an asy-stiff EoS parametrization 8/20

26 Reaction simulation Antisymmetrized Molecular Dynamics (AMD) It considers the evolution via the equations of motion of single nucleons, modeled as gaussian packets under the effect of a mean field and two-body interactions A. Ono et al., Phys. Rev. C 59, 853 (1999) 9/20

27 Reaction simulation Antisymmetrized Molecular Dynamics (AMD) It considers the evolution via the equations of motion of single nucleons, modeled as gaussian packets under the effect of a mean field and two-body interactions Gemini++ code Used as afterburner to produce secondary particle distributions from primary fragments A. Ono et al., Phys. Rev. C 59, 853 (1999) R. J. Charity, Phys. Rev. C 82, 0146 (20) 9/20

28 ISOFAZIA model data processing Dynamical model (AMD) Acquisition Primary products Raw data Calibration (kaliveda) Identified and calibrated products Analysis routine /20

29 ISOFAZIA model data processing Dynamical model (AMD) Acquisition Primary products Raw data Afterburner (GEMINI++) Secondary products Calibration (kaliveda) Identified and calibrated products Analysis routine /20

30 ISOFAZIA model data processing Dynamical model (AMD) Acquisition Primary products Raw data Afterburner (GEMINI++) Secondary products Calibration (kaliveda) Experimental filter Filtered secondary products Analysis routine Identified and calibrated products /20

31 Analysis event selection Z tot DIC central Kr + 48 Ca ϑ flow [deg] 5 M. D Agostino et al., Nucl. Phys. A 861, 47 (2011) 11/20

32 Analysis event selection Exp. data Z tot DIC central Kr + Ca ϑ flow [deg] 5 12/20

33 Analysis event selection Exp. data AMD + GEMINI++ Z tot DIC central 3 Z tot DIC central Kr + Ca ϑ flow [deg] Kr + Ca ϑ flow [deg] 5 Correlations are normalized to the same integral (1) M 2 condition has been imposed 12/20

34 Analysis event selection Exp. data AMD + GEMINI++ Z tot DIC central 3 Z tot DIC central Kr + Ca ϑ flow [deg] Kr + Ca ϑ flow [deg] 5 Correlations are normalized to the same integral (1) M 2 condition has been imposed AMD produces less central collisions than experimental data 12/20

35 Analysis event selection Z part Exp. data Kr + Ca DIC 3 Z part AMD + GEMINI Kr + Ca DIC Z part v cm 30 central 3 Z part v cm 30 central v proj v proj (lab) v part [mm/ns] (lab) v part [mm/ns] 13/20

36 Analysis isospin transport To study isospin transport we ll focus on the DIC channel Further selections In addition to the Z tot vs ϑ flow cut we impose: QP-only One fragment (QP) with Z 12 and v (cm) z > 0; no other fragments with Z 5 QP+QT One fragment (QP) with Z 12 and v z (cm) > 0; one fragment (QT) with Z 5 and ϑ (cm) rel > /20

37 Analysis isospin transport To study isospin transport we ll focus on the DIC channel Further selections In addition to the Z tot vs ϑ flow cut we impose: QP-only One fragment (QP) with Z 12 and v (cm) z > 0; no other fragments with Z 5 QP+QT One fragment (QP) with Z 12 and v z (cm) > 0; one fragment (QT) with Z 5 and ϑ (cm) rel > 160 Isospin diffusion could be evidenced by QP isotopic composition 14/20

38 Analysis isospin transport To study isospin transport we ll focus on the DIC channel Further selections In addition to the Z tot vs ϑ flow cut we impose: QP-only One fragment (QP) with Z 12 and v (cm) z > 0; no other fragments with Z 5 QP+QT One fragment (QP) with Z 12 and v z (cm) > 0; one fragment (QT) with Z 5 and ϑ (cm) rel > 160 Isospin diffusion could be evidenced by QP isotopic composition Isospin drift could be evidenced by neck emission isotopic composition 14/20

39 Analysis isospin diffusion <N>/Z Kr + 80 Kr + 80 Kr + 48 Ca QP-only selection 48 Ca QP+QT selection 40 Ca QP-only selection Kr + Ca QP+QT selection Z QP 15/20

40 Analysis isospin diffusion <N>/Z Kr + 80 Kr + 80 Kr + 48 Ca QP-only selection 48 Ca QP+QT selection 40 Ca QP-only selection Kr + Ca QP+QT selection Z = 25 limit of FAZIA isotopic discrimination! Z QP 15/20

41 Analysis isospin drift <N>/Z Kr + 80 Kr Kr + Kr + 48 Ca Z=3 48 Ca Z=4 40 Ca Z=3 40 Ca Z= (cm),//qp v [mm/ns] IMF 16/20

42 Analysis isospin drift <N>/Z Kr + 48 Ca, Z= Exp. data AMD (asystiff) + GEMINI++ AMD (asysoft) + GEMINI (cm),//qp v [mm/ns] IMF 16/20

43 Analysis neck emission <N>/Z Kr + 48 Ca Exp. data AMD (asystiff) + GEMINI++ AMD (asysoft) + GEMINI (neck) Z IMF 17/20

44 Analysis neck emission σ N Kr + 48 Ca Exp. data AMD (asystiff) + GEMINI++ AMD (asysoft) + GEMINI (neck) Z IMF 17/20

45 Analysis neck emission <N>/Z Kr + Ca σ N Kr + Ca Exp. data AMD (asystiff) + GEMINI++ AMD (asysoft) + GEMINI (neck) Z IMF Exp. data AMD (asystiff) + GEMINI++ AMD (asysoft) + GEMINI (neck) Z IMF The neck emission related observables are better reproduced by an asystiff EoS 18/20

46 Analysis neck emission <N>/Z Kr + Ca Exp. data AMD (asystiff) + GEMINI++ AMD (asysoft) + GEMINI (neck) Z IMF The neck emission related observables are better reproduced by an asystiff EoS Agreement with previous results from CHIMERA experiment E. De Filippo et al., Phys. Rev. C 86, 0146 (2012) 18/20

47 Conclusions and remarks The reactions 80 Kr + 40,48 Ca at 35 MeV/u have been studied: DIC channel described in this talk work in progress on more central collisions 19/20

48 Conclusions and remarks The reactions 80 Kr + 40,48 Ca at 35 MeV/u have been studied: DIC channel described in this talk work in progress on more central collisions FAZIA array allowed us to obtain: charge identification of all detected products isotopic discrimination up to Z 25 (even for QT!) 19/20

49 Conclusions and remarks The reactions 80 Kr + 40,48 Ca at 35 MeV/u have been studied: DIC channel described in this talk work in progress on more central collisions FAZIA array allowed us to obtain: charge identification of all detected products isotopic discrimination up to Z 25 (even for QT!) Comparison of isospin related observables with AMD code: possible evidence of asystiff behaviour of EoS 19/20

50 Conclusions and remarks The reactions 80 Kr + 40,48 Ca at 35 MeV/u have been studied: DIC channel described in this talk work in progress on more central collisions FAZIA array allowed us to obtain: charge identification of all detected products isotopic discrimination up to Z 25 (even for QT!) Comparison of isospin related observables with AMD code: possible evidence of asystiff behaviour of EoS We are still running AMD model code to have more simulated events and give more significance to our results 19/20

51 FAZIA collaboration Thanks for your attention 20/20

52 Backup Slides Si 1 analog chains x 1/4 P.A. x 4 d/dt ADCs 14 bit 0 MS/s 14 bit 250 MS/s 14 bit 250 MS/s circ buff circ buff circ buff TO FIFO fast filter slow filter TO FIFO TO FIFO S & H TO FIFO Local trigger box time stamp trigger request validation system clock circ buff TO FIFO fast filter Si 2 P.A. 14 bit 0 MS/s slow filter S & H TO FIFO FIFO To DAQ d/dt 14 bit 250 MS/s circ buff TO FIFO CsI(Tl) + PD P.A. 14 bit 0 MS/s circ buff TO FIFO fast filter fast filter S & H TO FIFO FPGA slow filter S & H TO FIFO

53 Backup Slides

54 Backup Slides