1 / 18

Optical Module Specifications for Dynamic Range, Time Resolution, Quantum Efficiency, Photon Counting, and Two-Track Sep

This article discusses the optical module specifications required for achieving dynamic range, time resolution, quantum efficiency, photon counting, and two-track separation in neutrino detectors. It covers topics such as background counting rate, angular and time resolution, quantum efficiency improvements, photon counting techniques, and the importance of dynamic range for various applications.

rizzom
Download Presentation

Optical Module Specifications for Dynamic Range, Time Resolution, Quantum Efficiency, Photon Counting, and Two-Track Sep

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Optical Module Specifications- WP2 point of viewP. Coyle, D. Dornic • Dynamic range • Two hit separation • Background counting rate • Time resolution • Quantum efficiency • Photon counting • Directionnality (cf following talk)

  2. Time Resolution I Angular resolution on neutrino dominated by physics of decay at low energies neutrino muon For energies ~100 TeV, physics allows angular resolution below 0.1 degrees Antares ~0.2 degrees, Amanda~2 degrees, Icecube~0.7 degrees

  3. Time Resolution II Angular resolution on muon track determined by: - lever arm - precise per hit - number of hits t  c t c N Larger lever arm in KM3NET allows good angular resolution while relaxing the requirement on the intrinsic time resolution 1 S  ~  S

  4. Time Resolution III Bailey Simulated 10 TeV muons in reference detector: TTS=1.5ns    delta_theta=0.08°   TTS=3ns      delta_theta=0.11°    TTS=6ns      delta_theta=0.22°  TTS=12ns    delta_theta=0.36°  → total time smearing of 3ns allows 0.1 degrees Without contribution of the neutrino cinematic

  5. Time Resolution IV The 3ns includes all contributions to time resolution - TTS from PMT - positioning resolution - electronics - calibrations Assume equal contributions from time and positioning: sigma T ~ 3ns/sqrt(2) ~ 2.1 ns Positioning and timing can be traded-off

  6. Quantum Efficiency I Higher quantum efficiency → higher efficiency for signal but larger K40 background rate and higher data rate per channel In order to take advantage of improved signal efficiency need reconstruction robust against background contamination This is the case for the Nessy reconstruction:

  7. Quantum Efficiency II e.g. 40% vs 23% Significant improvements : Factor ~2 @ 1 TeV Factor ~1.5 @ 10 TeV

  8. Quantum Efficiency III

  9. Photon Counting I Triggering - signal more likely to have >1 photons → desire very good 1 vs 2 photon separation → coincidence between pairs of PMTs or large pulse (>2.5spe) on single standard PMT (30%) Improved charge resolution could maximally improve the efficiency by 50%(prob in 2 PMs)*50% (cut at 2.5spe) ~ 25% But we only need 4-5 L1 to trigger……. Energy Measurement - measurement of dE/dX per unit length (see dynamic range discussion)

  10. Photon Counting II Antares simulation: E-2 spectrum Trigger 3N (standard ANTARES) a) 30% charge resolution, High amplitude threshold = 2.5 pe Trigger efficiency = 54% b) 1% charge resolution, High amplitude threshold = 1.5 pe Trigger efficiency = 64% Trigger 1T3a) 30% charge resolution, High amplitude threshold = 2.5 pe Trigger efficiency = 75%b) 1% charge resolution, High amplitude threshold = 1.5 pe Trigger efficiency = 82% In practice: increase of the trigger efficiency by ~ 10% With S. Escoffier

  11. Photon Counting III Test with a 217 lines hexagon with 34 storeys of 3 PMTs - With 30% charge resolution - With the true charge of each hits After the reconstruction level, with 1° quality cut: - average ratio : ~ 0.88

  12. Dynamic Range I • Dynamic range useful for: • Muon energy estimation – not usually contained in the detector • energy loss/unit length allows lower limit • → factor 2-3 energy estimate • Electron energy estimation – fully contained showers allow energy resolution ~20-30% • Identification of showers along muon track? • Multimuon rejection? • LED Beacon calibrations easier to understand if large dynamic range?

  13. Dynamic Range II Monte Carlo studies ongoing to evaluate importance of dynamic range for showers For now assume : 100spe/25ns with resolution 0.3 log (charge) cf Hammatsu PMT linear ~500spe/15ns Antares (with WFs) 200spe/25ns Antares (w/o WFs) 20spe/25ns Icecube 200pe/15ns

  14. Dynamic Range II

  15. Background Counting Rate Single photon background from K40 in sea dominates (350Hz/cm2) After the PMT (QE) ~ 40 kHz for the Antares PMT (10inch, 22% QE) Acceptable limit : 20% of the 40K contribution Other sources should be small cf to this: <10%

  16. CDR Specifications

  17. Two Track Separation I • Potentially useful for : • multi-muon rejection/measurement • Identification of charm (dimuons) in atmospheric neutrinos…... • Identification of NLKP signal in DM searches…..

  18. Two Track Separation II Antares integration gate ~35ns With Antares/NEMO waveforms can get what separation? Natural width of PM pulse (25ns) yields ~10m separation -seems reasonable

More Related