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NEDA (NEutron Detector Array) J.J. Valiente Dobon (LNL-INFN) on behalf of the NEDA collaboration.

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Presentation on theme: "NEDA (NEutron Detector Array) J.J. Valiente Dobon (LNL-INFN) on behalf of the NEDA collaboration."— Presentation transcript:

1 NEDA (NEutron Detector Array) J.J. Valiente Dobon (LNL-INFN) on behalf of the NEDA collaboration

2 Organization Spokeperson: J.J. Valiente Dobon (LNL-INFN) GANIL Liason: M. Tripon (GANIL) Steering committee: -B. Wadsworth (U. of York) -N. Erduram (U. of Istanbul) -L. Sttugge (IRES – Strasbodurg) -J. Nyberg (U. of Uppsala) -M. Palacz (U. of Warsaw) -A. Gadea (IFIC - Valencia) Members of the collaboration: U. of Ankara (Turkey), COPIN (Poland), CSIC-IFIC (Spain), Daresbury Laboratory (U.K.), GANIL (France), U. of Istanbul (Turkey), INFN (Italy), IRES (France), U. of Nidge (Turkey), U. of Uppsala (Sweeden), U. of York (U.K.) and Kolkata, India (under discussion) FP7-INFRASTRUCTURES SPIRAL2 PREPARATORY PHASE

3 Working groups Detector characteristics (Physics interests of NEDA to define the detector specifications). Responsible: B. Wadsworth Geometry (Make a full study of geometry to determine (materials) efficiency, reduce cross-talk,... Comparison between different codes: Geant4, MCNP-X. Simulate effect of other ancillaries, neutron scattering.). Responsible: M. Palacz Study New Materials (Exploring new materials, solid scintillators, deuterated liquid scintillators). Responsible: L. Stuttgé Digital Electronics (Flash ADCs, GTS, EXOGAM2 electronics,..) Responsible: A. Gadea PSA (Pulse shapes analysis, PSA algorithms,...). Responsible: J. Nyberg Synergies other detectors (Detectors that can be considered in synergy with NEDA: EXOGAM2, PARIS, AGATA, FAZIA, GASPARD, DIAMANT, DESCANT, Neutron spectroscopy at DESIR, DESPEC/HISPEC, NEUTROMANIA,... ). Responsible: P. Bednarczyk

4 Physics with NEDA Nuclear Structure –Probe of the T=0 correlations in N=Z nuclei: The structure beyond 92 Pd (Uppsala, LNL, GANIL, Stockholm, York) –Coulomb Energy Differences in isobaric multiplets: T=0 versus T=1 states (Warsaw, LNL, GANIL, York) –Coulomb Energy Differences and Nuclear Shapes (York, Padova, GANIL) –Low-lying collective modes in proton rich nuclei (Valencia, Istanbul, Milano, LNL, Krakow) Nuclear Astrophysics –Element abundances in the Inhomogeneous Big Bang Model (Weizmann, Soreq, GANIL) –Isospin effects on the symmetry energy and stellar collapse (Naples, Debrecen, LNL, Florence) Nuclear Reactions –Level densities of neutron-rich nuclei (Naples, LNL, Florence) –Fission dynamics of neutron-rich intermediate fissility systems (Naples, Debrecen, LNL, GANIL) NEDA will address the physics of neutron-rich as well as neutron deficient nuclei, mainly in conjunction with gamma-ray detectors arrays like AGATA, EXOGAM2, GALILEO and PARIS. AGATA: A. Gadea EXOGAM2: G. de France GALILEO: C. Ur PARIS: D. Jenkins AGATA: A. Gadea EXOGAM2: G. de France GALILEO: C. Ur PARIS: D. Jenkins

5 First day experiment Nuclear structure N=Z beyond 92 Pd : 96 Cd, etc AGATA/EXOGAM2 + NEDA

6 Low-lying collective modes in proton rich nuclei Second day experiment Transition densities PARIS + NEDA N=20

7 NEDA+PARIS experiment 34 Ar + 16 O → 44 Cr +  2n ( 34 Ar 10 8 pps) The reaction to study the Pigmy resonance in 44 Cr Courtesy M. Lewitowicz

8 Physics themes G de Angelis – Physics with NEDA G. de France - Results on the 92 Pd experiment A. Gottardo - Study of proton-rich nuclei with NEDA around A=100 A. Pipidis - NEDA: At the service of n-p correlations M. Palacz - Spectroscopy next to 100 Sn: 3n gating and where is 100 In? A. Di Nitto – The role of isospin in fusion-evaporation reactions G. Verde - The Farcos project and access to the symmetry energy with proton-neutron measurements

9 -NEDA: Neutron detector to be used coupled to AGATA/EXOGAM2/GALILEO/PARIS -Previous experience with the NWall (BC501) currently at GANIL -High efficiency 25% for one neutron. -Relatively good gamma/neutron discrimination. -Problems with cross talk. -Low efficiency for 2n (1-2%). -Analogic electronics. Problem definition

10 Neutron Wall

11

12 Neutron Wall: N=Z-2 A. Gadea et al., PRL97, (2006)S. Lenzi et al., PRL87, (2001) 24 Mg( 32 S,2n) 54 Ni 28 Si( 28 Si,2nα) 50 Fe

13 Cross talk – low 2n cross section High cross talk between neighboring detectors It is not possible to differenciate between 2n real events or just 1n scattered. Therefore neighbouring detectors are dismiss in the analysis and the efficiency decreases to 1-2%. One aim of NEDA is to be able to distinguish between real 2n events and scattered neutrons → Increase of the 2n efficiency. J. Ljungvall et al., NIMA (2004) Possible to improve 2n efficiency using TOF among detectors

14 Strategy of NEDA -Optimization of the geometry: unitary cell size, spherical, planar, zig-zag, granularity, distance, versatile. -FEE: GTS integrated in the motherboard and FADC in a mezzanine. Fully compatible with AGATA, GALILEO and EXOGAM2 -Use of the TOF information in addition to the measured energy to disentangle the 1n scattered events from the real 2n channels -Use of the deuterated scintillator BC537 -Pulse height seems to be proportional to incident neutron energy (reported by DESCANT collaboration) -Provides another method of determinig neutron energy beyond TOF -Can lead to a better discrimination of high multiplicity neutron events and scattered events. -New solid scintillators  Lawrence Livermore National Laboratory

15 BC501 vs. BC537 response Courtesy of P. Garrett, University of Guelph. BC537BC501A E n = 4.3 MeV E n = 2.5 MeV BC501BC537 DESCANT Presented by P. Garrett

16 Solid scintillators for neutron detection

17 Simulations Neutron HP model in G4.9.2.p01 (rel. March 2009) much improved comparing to earlier versions Total cross sections and angular distributions for elastic scattering on p, d, and 12 C reasonable Correct (high energy) γ-ray lines produced Wrong kinematics (angular distributions?) in the 12 C(n,α) 9 Be reaction. Important reactions still missing, like 12 C(n,n’)3α Existing defficiencies not significant in the <~10MeV energy range, which if interest for NEDA Presented by M. Palacz

18 Light output of liquid scintillator The light-output L is usually given in MeVee: the particle energy required to generate 1 MeVee of light is defined as 1 MeV for fast electrons L is generally less for heavier particles such as protons, deuterons, alphas, beryllium, carbon… Therefore, the light output L in a certain path dx is a function of the deposited energy E in dx: L(E) Dekempeneer et Liskien NIM A 256 (1987) Deposited energyLight output Presented by A. Gottardo

19 Geometry study Definition of the unitary cell dimensions Presented by G. Jaworski

20 Geometries There are two possible main geometries, either spherical or planar. The spherical geometry presents the full symmetry. The planar has some advantages, than the spherical does not present. -Flexibility – different arrangements of the detectors, e.g. zig-zag -Different focal posistions (500cm, 1000cm, 2000cm) -Budget issues

21 Performance of diff. geometries FlatZig-zagSpherical BC501A BC537 Presented by T. Hüyük

22 Discriminating neutron/gamma Pulse shapes from the detector differs between neutrons and gamma rays. Usually both pulse shape analysis and the time-of-flight information is used for discrimination neutron- gamma discrimination. neutrons

23 Digital electronics: PSA It is possible to obtain better quality using same algorithms but digital electronics Analog zero-crossover method

24 Applying an artificial neural network can increase the quality even further Digital electronics: Neural Network P=sqrt(ε n 2 +ε γ 2 )

25 GTS supervisor Event Builder PSA Pre-processing Digitizer Tracking Online analysis GTS local prompt trigger REQ VAL REQ VAL Global Merger GAMMA-ARRAY GTS local Event Builder PSA Pre-processing Digitizer NEDA NEDA coupled to AGATA/EXOGAM2

26 MGT Clocks Fast serial links Parallel links Slow control Serial link Digital electronics: EXOGAM2-NEDA Basic diference EXOGAM2/NEDA is the ADC: MHz 12-14bit Presented by M. Tripon

27 Silicon Photo multipliers readout Direct replacement for photomultiplier tube Insensitive to magnetic fields Can operate in vacuum Large sizes possible Attractive for simultaneous PET and MRI scanning SPMPlus Synergy with PARIS – D. Jenkins

28 BC501A and BC537 detectors Currently bought commercial detectors from Saint Gobain Two detectors 5”x5” BC537 (LNL-INFN) Two detectors 5”x5” BC501A (York-Valencia) A. Pipidis (founded SP2PP) working on the characterization of the detectors.

29 Summary Currently bought BC537 and BC501A commercial detectors to test: –cross talk –light production –FADC – frecuency and number of bits – PSA – neutron-gamma discrimination First contacts with Livermore – Start up collaboration solid scintillators? Test of SPMPlus from York in BC537 and BC501A Development of electronics in synergy with EXOGAM2 Optimal geometry

30 Workshop program

31 Phases of NEDA The current development on new materials and readout systems for neutron detection makes necessary to build NEDA in four different phases: Phase 0: Upgrade of Neutron Wall with digital electronics. Phase 1: R&D on new material and light readout systems for a highly segmented neutron detector array. Phase 3: Construction of a limited size Demonstrator Phase 4: Final construction of NEDA

32 With current technological status … Three main options: –200 detectors BC501A – PM readout –Digital electronics Total cost: 600K€ (BC501A) + 200K€(Elec.) + 40K€ (mechanics) = 840 K€ –200 detectors BC536 – PM readout – Digital electronics Total cost: 2000K€ (BC537) + 200K€(Elec.) + 40K€ (mechanics) = 2240 K€ –Upgrade Neutron Wall - Phase 0 (Digital electronics) Total cost (50 channels) = 40K€

33 Collaborating Institutes Centro Superior de Investigaciones Cientificas (CSIC) – Valencia Grand Accelerateur National d’Ions Lourds (GANIL) Istituto Nazionale di Fisica Nucleare – Laboratori Nazionale di Legnaro Royal Institute of Technology - KTH University of Istanbul University of Lund University of Nidge University of Uppsala University of Warsaw University of York

34 Summary and future work NEDA – Looks at improving efficiency for 2n channels – BC537, geometry Validated simulatons – realistic results for BC501 and BC537 Included model for light production. PSA algorithms to discriminate neutron-gamma – Neural Network great perspectives. Synergies –PARIS (A. Maj): SPMPlus, electronics? –EXOGAM (G. De France): electronics –Neutron Spectroscopy at DESIR (D. Cano & N. Orr): Simulations, FADC FUTURE WORK Currently bought BC537 and BC501 commercial detectors to test: –cross talk –light production – PSA – neutron-gamma discrimination Test of SPMPlus from York in BC537 and BC501 Development of electronics in synergy with EXOGAM2 Design of FADC mezzanines Optimal geometry

35 NEDA possible geometries Step-spherical Spherical

36 Neutron-γ discrimination BC537 n-γ discrimination BC501A(D) n-γ discrimination

37 Light output

38 Time scale Q4Q1Q2Q3Q4Q1Q2Q3 Validation GEANT4 neutron simulations Geometry definition Digital algorithms for PSA Detector prototype Test prototype Electronics Negoziations MoU MoU signature

39 Silicon PM

40 Synergies EXOGAM array PARIS

41 Commercial electronics: Struck 4 channel VME digitizer/transient recorder with a sampling rate of up to 500 MS/s (for the individual channel) and 12-bit resolution Programmable FPGAs

42 Intrinsic efficiency of BC501A and BC537


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