Presentation on theme: "NEDA (NEutron Detector Array)"— Presentation transcript:
1NEDA (NEutron Detector Array) J.J. Valiente Dobon (LNL-INFN)on behalf of the NEDA collaboration
2Organization 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-INFRASTRUCTURESSPIRAL2 PREPARATORY PHASE
3Working groupsDetector characteristics (Physics interests of NEDA to define the detector specifications).Responsible: B. WadsworthGeometry (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. PalaczStudy New Materials (Exploring new materials, solid scintillators, deuterated liquid scintillators).Responsible: L. StuttgéDigital Electronics (Flash ADCs, GTS, EXOGAM2 electronics, ..)Responsible: A. GadeaPSA (Pulse shapes analysis, PSA algorithms, ...).Responsible: J. NybergSynergies 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
4Physics with NEDA AGATA: A. Gadea EXOGAM2: G. de France GALILEO: C. Ur 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.Nuclear StructureProbe of the T=0 correlations in N=Z nuclei: The structure beyond 92Pd (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 AstrophysicsElement abundances in the Inhomogeneous Big Bang Model (Weizmann, Soreq, GANIL)Isospin effects on the symmetry energy and stellar collapse (Naples, Debrecen, LNL, Florence)Nuclear ReactionsLevel densities of neutron-rich nuclei (Naples, LNL, Florence)Fission dynamics of neutron-rich intermediate fissility systems (Naples, Debrecen, LNL, GANIL)AGATA: A. GadeaEXOGAM2: G. de FranceGALILEO: C. UrPARIS: D. Jenkins
6Second day experiment Low-lying collective modes in proton rich nuclei PARIS + NEDALow-lying collective modes in proton rich nucleiN=20Transition densities
7NEDA+PARIS experiment Courtesy M. LewitowiczThe reaction to study the Pigmy resonance in 44Cr34Ar + 16O → 44Cr + 2n (34Ar 108 pps)
8Physics themes G de Angelis – Physics with NEDA G. de France - Results on the 92Pd experimentA. Gottardo - Study of proton-rich nuclei with NEDA around A=100A. Pipidis - NEDA: At the service of n-p correlationsM. Palacz - Spectroscopy next to 100Sn: 3n gating and where is 100In?A. Di Nitto – The role of isospin in fusion-evaporation reactionsG. Verde - The Farcos project and access to the symmetry energy with proton-neutron measurements
9Problem definition-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.
12Neutron Wall: N=Z-2 28Si(28Si,2nα)50Fe 24Mg(32S,2n)54Ni S. Lenzi et al., PRL87, (2001)A. Gadea et al., PRL97, (2006)
13Cross talk – low 2n cross section High cross talk between neighboring detectorsIt 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%.J. Ljungvall et al., NIMA (2004)Possible to improve 2n efficiency using TOF among detectorsOne aim of NEDA is to be able to distinguish between real 2n events and scattered neutrons → Increase of the 2n efficiency.
14Strategy 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 BC537Pulse 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
15BC501 vs. BC537 response Presented by P. Garrett BC501 BC537 DESCANTEn = 2.5 MeVEn = 4.3 MeVBC501ABC537Courtesy of P. Garrett, University of Guelph.
17Simulations Presented by M. Palacz Neutron HP model in G4.9.2.p01 (rel. March 2009) much improved comparing to earlier versionsTotal cross sections and angular distributions for elastic scattering on p, d, and 12C reasonableCorrect (high energy) γ-ray lines producedWrong kinematics (angular distributions?) in the 12C(n,α)9Be reaction.Important reactions still missing, like 12C(n,n’)3αExisting defficiencies not significant in the <~10MeV energy range, which if interest for NEDA
18Light 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 electronsL 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)Deposited energyLight outputPresented by A. GottardoDekempeneer et Liskien NIM A 256 (1987)
19Geometry study Presented by G. Jaworski Definition of the unitary cell dimensions
20GeometriesThere 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
21Performance of diff. geometries FlatZig-zagSphericalBC501ABC537Presented by T. Hüyük
22Discriminating neutron/gamma Pulse shapes from the detector differs between neutrons and gamma rays.neutronsUsually both pulse shape analysis and the time-of-flight information is used for discrimination neutron- gamma discrimination.
23Digital electronics: PSA It is possible to obtain better quality using same algorithms but digital electronicsAnalog zero-crossover method
24Digital electronics: Neural Network Applying an artificial neural network can increase the quality even furtherP=sqrt(εn2+εγ2)
25NEDA coupled to AGATA/EXOGAM2 Digitizerprompt triggerDigitizerREQVALREQVALPre-processingGTSlocalGTSlocalPre-processingNEDAGAMMA-ARRAYPSAPSAEvent BuilderGTSsupervisorEvent BuilderGlobal MergerTrackingOnline analysis
26Basic diference EXOGAM2/NEDA is the ADC: 200-300 MHz 12-14bit Digital electronics: EXOGAM2-NEDAMGTClocksFast serial linksParallel linksSlow controlSerial linkPresented by M. TriponBasic diference EXOGAM2/NEDA is the ADC: MHz 12-14bit
27Silicon Photo multipliers readout SPMPlusDirect replacement for photomultiplier tubeInsensitive to magnetic fieldsCan operate in vacuumLarge sizes possibleAttractive for simultaneous PET and MRI scanningSynergy with PARIS – D. Jenkins
28Currently bought commercial detectors from Saint Gobain BC501A and BC537 detectorsCurrently bought commercial detectors from Saint GobainTwo detectors 5”x5” BC537 (LNL-INFN)Two detectors 5”x5” BC501A (York-Valencia)A. Pipidis (founded SP2PP) working on the characterization of the detectors.
29SummaryCurrently bought BC537 and BC501A commercial detectors to test:cross talklight productionFADC – frecuency and number of bits– PSA – neutron-gamma discriminationFirst contacts with Livermore – Start up collaboration solid scintillators?Test of SPMPlus from York in BC537 and BC501ADevelopment of electronics in synergy with EXOGAM2Optimal geometry
31Phases of NEDAThe 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
33Collaborating Institutes Centro Superior de Investigaciones Cientificas (CSIC) – ValenciaGrand Accelerateur National d’Ions Lourds (GANIL)Istituto Nazionale di Fisica Nucleare – Laboratori Nazionale di LegnaroRoyal Institute of Technology - KTHUniversity of IstanbulUniversity of LundUniversity of NidgeUniversity of UppsalaUniversity of WarsawUniversity of York
34Summary and future work NEDA – Looks at improving efficiency for 2n channels – BC537, geometryValidated simulatons – realistic results for BC501 and BC537Included model for light production.PSA algorithms to discriminate neutron-gamma – Neural Network great perspectives.SynergiesPARIS (A. Maj): SPMPlus, electronics?EXOGAM (G. De France): electronicsNeutron Spectroscopy at DESIR (D. Cano & N. Orr): Simulations, FADCFUTURE WORKCurrently bought BC537 and BC501 commercial detectors to test:cross talklight production– PSA – neutron-gamma discriminationTest of SPMPlus from York in BC537 and BC501Development of electronics in synergy with EXOGAM2Design of FADC mezzaninesOptimal geometry
35NEDA possible geometries Step-sphericalSpherical