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Preliminary study of electron/ hadron discrimination with the NEUCAL detector

11th ICATPP - Conference on Astroparticle , Particle, Space Physics, Detectors and Medical Physics Applications 5-9 October 2009, Villa Olmo (Co), Italy. Preliminary study of electron/ hadron discrimination with the NEUCAL detector. Lorenzo Bonechi University and INFN – Florence (Italy).

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Preliminary study of electron/ hadron discrimination with the NEUCAL detector

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  1. 11th ICATPP - Conference on Astroparticle, Particle, Space Physics, Detectors and Medical Physics Applications 5-9 October 2009, Villa Olmo (Co), Italy Preliminary study of electron/hadron discrimination with the NEUCAL detector Lorenzo Bonechi University and INFN – Florence (Italy)

  2. The NEUCAL working group O. Adriani1,2, L. Bonechi1,2, M. Bongi2, S. Bottai2, G. Castellini3, R. D’Alessandro1,2, M. Grandi2, P. Papini2, S. Ricciarini2, G. Sguazzoni2, G. Sorichetti1, P. Sona1,2, P. Spillantini1,2, E. Vannuccini2, A. Viciani2 University of Florence INFN Section of Florence IFAC – CNR, Florence ICATPP 2009 - Lorenzo Bonechi

  3. Outline of this presentation • Basic ideas • e/hadrons discrimination with e.m. calorimeters • Use of neutron detectors (PAMELA experiment) • The new NEUCAL concept • Simulations • The prototype detector • Description of apparatus and assembling • Test beam at CERN SPS (August 2009) • Event show and first preliminary comparison with the GEANT4 simulation ICATPP 2009 - Lorenzo Bonechi

  4. PART 1 Basic ideas ICATPP 2009 - Lorenzo Bonechi

  5. e/hadrons discrimination in HEP Two events detected by the PAMELA space experiment 36 GeV/c proton 18 GeV/c electron SILICON TRACKER MAGNET TRIG. SCINTI. E.M. CALO • Common requirement for HEP experiments • particularly important for those devoted to Astroparticle Physics • Electromagnetic calorimeters • very good discrimination capability in a wide energy range ICATPP 2009 - Lorenzo Bonechi

  6. The situation at higher energy • Interacting protons with energy beyond few hundreds GeV can be tagged as electrons due to • similar energy release in calorimeter than electrons • similar shower development than electrons • It is not possible, especially for space experiments, to increase too much the calorimeter depth • strong limitation in weight and power consumption • Complementary detectors, like trackers, cannot help easily at these energies ICATPP 2009 - Lorenzo Bonechi

  7. The use of a neutron counter in PAMELA 18 GeV/c electron 36 GeV/c proton • Neutron production: • Protons: nuclear excitation, hadronic interaction and Giant Resonance • Electrons: only through the Giant Resonance • Differentyield in neutronproduction are expected for e.m. or hadronic showers • New idea in PAMELA: use a neutron counter as the final stage of the apparatus (beyond calorimeter) ICATPP 2009 - Lorenzo Bonechi

  8. Detection of neutrons produced inside the calorimeter: the NEUCAL concept New idea in NEUCAL: • Study of the moderation phase using an active moderator • Standard plastic scintillators are rich in hydrogen and then suitable as moderators(EljenEJ-230  [CH2CH(C6H4CH3)]n ) • Detection of: • signals due to neutron elastic/inelastic scattering • signals due to absorption of neutrons by 3He (proportional tubes) n PMT or Si-PMT SCINT 3He tube PAMELA: Moderation of neutrons by means of passive moderator (polyethylene layers) 3He proportional tubes to absorb thermal neutrons and detect signals due to the ionization of products inside gas n + 3He  3H + p (Q = 0.764 MeV) ICATPP 2009 - Lorenzo Bonechi

  9. PART 2 Simulation ICATPP 2009 - Lorenzo Bonechi

  10. Few details and results 12 scintillator layers BGO tiles 30 X0 NEUCAL 3He Tubes (1 cm diam.) • First results based on FLUKA, now implementing also GEANT4 simulation • Detector geometry has been dimensioned for application together with a 30 X0 calorimeter (CALET experiment) • NEUCAL is placed downstream a 30 X0 deep homogeneous BGO calorimeter ICATPP 2009 - Lorenzo Bonechi

  11. Distribution of number of neutrons Note: energy release inside the BGO calorimeter is almost the same for 1TeV protons and 400 GeV electrons. 1 TeV protons 400 GeV electrons FLUKA FLUKA ICATPP 2009 - Lorenzo Bonechi

  12. Scatter plot: arrival timevsneutron energy Almost all neutrons exit from the calorimeter within a few microseconds, but thermalization inside neucal can take hundreds microseconds 1 keV 1 MeV 1 GeV Arrival time (seconds) 1 s 100 ns 10 ns Outgoing neutron energy Log (E(GeV)/1GeV) ICATPP 2009 - Lorenzo Bonechi

  13. Expected performance (comparison FLUKA/GEANT4) FLUKA simulated energy release inside one scintillator layer See also: S.Bottai et al., at Frontier Detector for Frontier Physics, La Biodola (Elba), 24-30 May 2009 Neutrons up to few MeV kinetic energy are moderated and detected with high efficiency. At 10 MeV 70% of neutrons gives detectable signals. Only 10% are fully moderated to be detectable by the 3He Tubes ENTRIES 1 MeV neutrons ENTRIES 10 MeV neutrons ICATPP 2009 - Lorenzo Bonechi

  14. PART 3 The prototype detector ICATPP 2009 - Lorenzo Bonechi

  15. Production of scintillators Light guides: simple plexiglas One side covered with aluminized tape Scintillator material: Eljen Technology, type EJ-230 (PVT, equivalent to BC-408) ICATPP 2009 - Lorenzo Bonechi

  16. Production of prototype detecting modules PMT Hamamatsu R5946 Optical grease: Saint Gobain BC-630 ICATPP 2009 - Lorenzo Bonechi

  17. Production of the first module 3He proportional counter tube: Canberra 12NH25/1 1 cm diameter ICATPP 2009 - Lorenzo Bonechi

  18. Prototype assembly 3x3 matrix of scintillator modules with 5 3He proportional counter tubes integrated 1 cm diameter 3He tubes PMT light guide scintillator ICATPP 2009 - Lorenzo Bonechi

  19. Digitalization electronics • CAEN V1731 board • VME standard • 8 ch, 500MS/s • 8 bit ADC • 2MB/ch memory (few ms digitization) • 16 ns jitter • On-board data compression (Zero Suppression Encoding) • CAEN V1720 board • VME standard • 8 ch, 250MS/s • 12 bit ADC • 2MB/ch memory (few ms digitization) • 32 ns jitter • On-board data compression (Zero Suppression Encoding) ICATPP 2009 - Lorenzo Bonechi

  20. PART 4 Test beam at CERN SPS (August 2009) ICATPP 2009 - Lorenzo Bonechi

  21. Integration of the NEUCAL prototype with a 16 X0 tungsten calorimeter (25 July 2009) CALORIMETER NEUCAL ICATPP 2009 - Lorenzo Bonechi

  22. CALORIMETER ICATPP 2009 - Lorenzo Bonechi

  23. Beam test details • CERN SPS, line H4 (one week test) • Beam type – energy - # of events: • Pions 350 GeV ( 230000 events) • electrons 100 GeV ( 240000 events) • electrons 150 GeV ( 50000 events) • muons 150 GeV(130000 events) • Data collected in different configurations • scan of detector (beam impact point) • different working parameters • PMTs and tubes voltages • Digitizer boards parameters (thresholds, data compression…) ICATPP 2009 - Lorenzo Bonechi

  24. Detectors’ configuration NEU CAL 16 X0 W CALO ELECTRON beam Total thickness upstream NEUCAL: 16 X0 NEU CAL 16 X0 W CALO PION beam 9 X0 Pb 2.25 X0 PbWO4` 30 Total thickness upstream NEUCAL: (16+13) X0 Next slides report a comparison of data with GEANT4 simul. for electron and pion events taken in the following configurations: ICATPP 2009 - Lorenzo Bonechi

  25. How to find neutron signals? Trigger Prompt signal Particle signal ? Scint. A time Particle signal Prompt signal Scint. B time t=0 t10us t=1ms • Digitalization of scint. output for a long time interval (1ms) • Look for signals which are not in time with other signals on other channels: • Avoid the prompt signals due to charged particles coming directly from the shower • Avoid single charged particles giving signals on more then one scintillator (non interacting hadrons entering the detector ICATPP 2009 - Lorenzo Bonechi

  26. Digitalization of one muon event Trigger signals UPSTREAM t ~700ns 1 2 3 t = 0 4 5 Bounces are due to additional filters on the digitizer inputs to solve a problem of firmware (loss of fast signals) Scintillators 3He tubes DOWNSTREAM ICATPP 2009 - Lorenzo Bonechi

  27. Digitalization of one electron event Trigger signals UPSTREAM 1 2 3 All signals rise at t = 0 (prompt shower secondaries) 4 5 Scintillators 3He tubes DOWNSTREAM ICATPP 2009 - Lorenzo Bonechi

  28. Digitalization of pion events (1) Trigger signals UPSTREAM 1 2 3 t ~34 s 4 5 t ~100 s Scintillators 3He tubes DOWNSTREAM ICATPP 2009 - Lorenzo Bonechi

  29. Digitalization of pion events (2) Trigger signals UPSTREAM 1 3 2 t ~46.8s t ~28.5s 5 4 t ~250s Scintillators 3He tubes DOWNSTREAM ICATPP 2009 - Lorenzo Bonechi

  30. Digitalization of pion events (3) Trigger signals UPSTREAM t ~14.6s t ~170s 1 2 3 t ~250s 4 5 t ~12.6s Scintillators 3He tubes DOWNSTREAM ICATPP 2009 - Lorenzo Bonechi

  31. First preliminary comparison data/MC • 33000 events • “single” signals • one single central PMT • GEANT4 • data 100 GeV ELECTRONS Instrumental effect ? ENERGY Spurious particles ARRIVAL TIME ICATPP 2009 - Lorenzo Bonechi

  32. First preliminary comparison data/MC • 75000 events • “single” signals • one single central PMT • GEANT4 • data 350 GeV PIONS ? ENERGY Spurious particles ARRIVAL TIME ICATPP 2009 - Lorenzo Bonechi

  33. Comparison data/MC: signal energy distribution 33000 ELECTRON events GEANT4 PRELIMINARY 75000 PION events GEANT4 PRELIMINARY ICATPP 2009 - Lorenzo Bonechi

  34. Comparison data/MC: time distribution 33000 ELECTRON events GEANT4 PRELIMINARY 75000 PION events GEANT4 ICATPP 2009 - Lorenzo Bonechi

  35. Conclusions • A new neutron detector, NEUCAL, is under study for particle identification purposes • Its aim is to help e.m. calorimeters in e/hadron separation at H.E. • New idea: use an active moderator (plastic scintillator) to moderate the neutrons and detect their signals simoultaneously • A prototype has been developed e tested with charged particles during a beam test at CERN SPS (August 2009) • First very preliminarycomparison between data and GEANT4 simulation shows substantial agreement, even if some effects is not yet understood (instrumental effect?) ICATPP 2009 - Lorenzo Bonechi

  36. Backup slides ICATPP 2009 - Lorenzo Bonechi

  37. Expected performance Simulated energy release inside NEUCAL (12 scintillator layers detector) S.Bottai et al., at Frontier Detector for Frontier Physics, La Biodola (Elba), 24-30 May 2009 Neutrons up to few MeV kinetic energy are moderated and detected with high efficiency. At 10 MeV 70% of neutrons gives detectable signals. Only 10% are fully moderated to be detectable by the 3He Tubes ICATPP 2009 - Lorenzo Bonechi

  38. Filter ICATPP 2009 - Lorenzo Bonechi

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