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Rezo Shanidze, Sebastian Kuch

Design Studies for the KM3NeT Neutrino Telescope. Rezo Shanidze, Sebastian Kuch. KM3NeT WP2 Meeting Catania, Italy, 30 - 31 October 2007. Introduction. Summary of simulations (1 step): Sebastian Kuch, FAU-PI1-DISS-07-001 Design Studies for the KM3NeT Neutrino Telescope

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Rezo Shanidze, Sebastian Kuch

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  1. Design Studies for the KM3NeT Neutrino Telescope Rezo Shanidze, Sebastian Kuch KM3NeT WP2 Meeting Catania, Italy, 30 - 31 October 2007

  2. Introduction • Summary of simulations (1 step): • Sebastian Kuch, FAU-PI1-DISS-07-001 • Design Studies for the KM3NeT • Neutrino Telescope • (available from KM3NeT portal) • Aim of the thesis: • … to provide starting point for • the definition of a detector • design for the KM3NeT • neutrino telescope in • the Mediterranean sea • with an instrumented • volume of a cubic • kilometer scale. KM3NeT WP2, Catania, Italy

  3. KM3NeTDetector Models • Two aspects of a neutrino telescope were studied: • layout of a single cluster of PMT, called • a storey. • positions of the storeys in the • instrumented volumeor detector geometry. • The KM3NeT parameters fixed during simulation: • - instrumented volume ~1 km3 ( 1% precision 1 km3 To avoid overlap of the parameters, KM3NeT performance was studied for: - same geometry g for different storey types - same storey g for different geometry configurations Detector performance parameter used for the comparison of the different detector models:Effective area (for nm) KM3NeT WP2, Catania, Italy

  4. I. Neutrino Interactions • NC interactions • ne CC interactions • nm CC interactions • nt CC interactions • Energy range considered: • 10 < En < 107 GeV • Low energy sample for DM • studies: 1 < En < 500 GeV • not considered in this study: • - atm-m background • - Cherenkov photons from • the particles in a shower. KM3NeT WP2, Catania, Italy

  5. Software and Analysis Tools • ANTARES Software: • - Detector modeling • - Event generation • - Detector Simulation • - Trigger Software • - Reconstruction • Analysis Methods • - Effective area • - Angular resolution • - Event Selection Critera • Calculation of neutrino flux • limits for E-2 case. ANTARES software: used for MC production and selection and reconstruction of events (data/MC). Documented in software notes. KM3NeT WP2, Catania, Italy

  6. Event Samples & Simulation Parameters • Simulated events: • nm charged current interactions: nmN gm- + X • Standard nm event sample: 10 GeV <En < 10 PeV (En-1.4) • 2·109nm for each detector configuration, 4p isotropic Bkg included: C-photons from 40K: 40KHz/10” PMT ( 91 Hz/cm2 ) Hits: > 0.5 p.e. (Gaussian gain fluctuations) KM3NeT WP2, Catania, Italy

  7. Different Story Types for KM3NeT Different storeys used in the KM3NeT simulations are presented in the figures(a-g) and table. In addition configurations with 20” PMT (single, ANTARES type) were considerd. H - Hamamatsu P - Photonis

  8. Paramters of the PMTs List of the PMT parameters used in the simulations: Quantum efficiency QE(l), Angular acceptance, Transit time spread(TTS). QE(l) and angular acceptance of 10” PM (Hamamatsu R7081) KM3NeT WP2, Catania, Italy

  9. Detector Model for Different Storeys 484 strings (22 x 22), Lstring = 567 m, distance between lines: 63 m Additional geometries were created, where number of storeys per string is adjusted to obtain a same total photocathode area, as for a standard detector ( cubiid with ANTARES storeys) . By comparing these configurations (candidate type detectors) , differences between photodetection systems can be studied.

  10. Event Selection Criteria Reconstructed m track : 5 parameters: - Space point: x, y, z - Direction: Q, f m Q,f (x,y,z) Table 6.1 from chapter 6( Analysis methods) KM3NeT WP2, Catania, Italy

  11. Detector with ANTARES Storeys Neutrino effective are of a homogeneous cuboid grid detector, with ANTARES storeys (reference detector), at different selection steps. KM3NeT WP2, Catania, Italy

  12. Detector with ANTARES Storeys Number of events in the neutrino event sample (109nm events) of a homogeneous cuboid grid detector, with ANTARES storeys, at different selection steps. KM3NeT WP2, Catania, Italy

  13. Detectors with 10” PMTs 10” detector with diff, storeys: effective areas and ratios fordifferent selected criterion. KM3NeT WP2, Catania, Italy

  14. Candidate Detectors with 10” PMTs KM3NeT WP2, Catania, Italy

  15. Storeys with 10” PMTs (Section summary) • The effective area generally increases with increasing • photocathode area. • The ability to utilise local coincidences increases the performance • for the hit, trigger and selection criteria. • The reconstruction strategy appears to be slightly biased towards • the ANTARES storey structure. • The single and double PMT/storey detectors are significantly worse, • than reference detector (cuboid with ANTARES storey) at the hit, • trigger and selected level. KM3NeT WP2, Catania, Italy

  16. Detector Storeys with 3” PMT Multi-PMT ( P.Kooijman, NIM A567(2007), 508 ) pro: high QE, short TTS, good 2-photon separation, stability contra: lack of experience QE and angular acceptance (‘flat disc”) for 3” PMT (XP53X2) used in the Multi-PMT storey detector simulations KM3NeT WP2, Catania, Italy

  17. Detector Storeys with 3” PMTs Different Multi-PMT storey layouts: 1) ‘cylindrical’ : 12 PMT/cylinder ( ~ 10’’ photocathode area) ANTARES type story: 3 Multi-PMT cyl: 36 PMT 2) Spherical storey (17” sphere): - 42 PMTs ( 4p –max possible) (8 storey/L, 82 m spacing) - 21 PMT ( 2p) (20 storey/L, 31.5 m spacing) KM3NeT WP2, Catania, Italy

  18. Detector with Multi-PMT Storey KM3NeT WP2, Catania, Italy

  19. Storeys with 3” PMTs KM3NeT WP2, Catania, Italy

  20. Some Conclusions for Photodetectors • Photocathode area ( x QE) is most important factor defining the Neutrino • detector effective area. • Single PMT/storey detectors have poor background (40K) rejection • capabilities and have worst performance with used m-reconstruction • algorithms. • Multi-PMT storey with (3” PMT) provides promising alternative to • ANTARES like configurations ( with 10” PMTs). • For the same photocathode area Multi-PMT detectors have additional • advantages, such as larger number of storeys (for 21 PMT configuration) • and better PMT parameters. KM3NeT WP2, Catania, Italy

  21. KM3NeT Detector Geometries 5 different types of geometries are considered: 1-3) Ring, clustered, cuboid geometries 4) Beyond the cubic kilometer 5) IceCube comparable (ICC), Ring geometry Cluster geometry Cuboid geometry Same storey is used for these configurations: ANTARES type Multi-PMT (3 x 12 X 3”PMT) storey (cyl)

  22. KM3NeT Ring Geometries Ring 1 Ring 2 Ring 3 Ring 4 KM3NeT WP2, Catania, Italy

  23. Ring Geometries Moderate Moderate Selected Selected KM3NeT WP2, Catania, Italy

  24. Ring Geometries KM3NeT WP2, Catania, Italy

  25. KM3NeT Clustered Geometries Main motivation: increase of efficiency at low neutrino energies. Total PMT area for all 3 configuration: 701 m2 Different geometry configuration of similar clusters in a volume of 1.007 (1.0035) km3 for cluster1, 2 (3). Cluster 1 Cluster 2 Cluster 3 KM3NeT WP2, Catania, Italy

  26. Clustered Geometries Selected Selected Selected Selected KM3NeT WP2, Catania, Italy

  27. Clustered Geometries KM3NeT WP2, Catania, Italy

  28. KM3NeT Cuboid Geometries KM3NeT WP2, Catania, Italy

  29. KM3NeT Cuboid Geometries Selected Selected Selected Selected KM3NeT WP2, Catania, Italy

  30. Beyond the Cubic Kilometer

  31. Beyond the Cubic Kilometer

  32. IceCube Comparable Geometry Detectors with different geometries but same IceCube type lines (IceCube comparable ICC) and storey : ICCcube, ICCring, ICCcluster, with Lstring=1000 m IceCube ICCcluster ICCcube ICCring KM3NeT WP2, Catania, Italy

  33. Comparison with IceCube KM3NeT WP2, Catania, Italy

  34. Detectors Geometries: Summary • Different detector configurations simulated for 1km3 instrumented • volume (ring, clustered, cube, extended, IceCube comparable). • Within considered detector configurations there is no single one • which is preferable at all considered energies (10 < En < 107 GeV) • For low energies (En < ~103 GeV) clustered and ring geometries • have larger effective area. • For high energy (En > 103 GeV) effective area for the clustered • configurations are significantly worse. • Detector is with cuboid configuration (Cube 2) was selected as an • example detector for the further studies. KM3NeT WP2, Catania, Italy

  35. Example of KM3NeT detector + + 21 3” PMTs per storey 36 storeys per string 225 strings (15 x 15) KM3NeT WP2, Catania, Italy

  36. KM3NeT Effective Area The neutrino Effective area (Aeff(En)) of the “Example detector” at different selection steps. The true Aeff(En) will be between minimal and selected (reconstructed) criteria. KM3NeT WP2, Catania, Italy

  37. Summary and Outlook • Different models for the KM3NeT detector were simulated, • corresponding to several storeys (photo-detection systems) • and geometrical configurations. • For considered KM3NeT models neutrino effective area were • calculatedand compared for the selection of ‘KM3NeT candidate • configurations’. • For the Mediterranean Neutrino Telescope the ANTARES-type or • Multi-PMT storey detector has a significant advantage in background • reduction, event triggering and reconstruction. • Photocathode area of the detector is the most important parameter • in the effective area calculations. • Optimization of m-reconstruction and selection criteria is necessary • step in the selection of the final configuration. KM3NeT WP2, Catania, Italy

  38. Detector Summary KM3NeT WP2, Catania, Italy

  39. Detector Summary KM3NeT WP2, Catania, Italy

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