G Rodriguez Tank Calibration

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G Rodriguez Tank Calibration

  1. 1. Tank Calibration Pierre Auger Observatory Gonzalo Rodriguez Universidad de Santiago de Compostela Astroparticle group for the Pierre Auger Collaboration 1 Trasgo Project
  2. 2. Pierre Auger Observatory research goals • Energy Spectrum of UHECR (E > 1018 eV) -> Shape of the spectrum in the region of the GZK feature • Arrival Direction Distribution -> Search for departure from isotropy - point sources • Mass Composition: nuclei, photons, neutrinos, etc. 2
  3. 3. Pierre Auger Observatory research goals • Energy Spectrum of UHECR (E > 1018 eV) -> Shape of the spectrum in the region of the GZK feature • Arrival Direction Distribution -> Search for departure from isotropy - point sources • Mass Composition: nuclei, photons, neutrinos, etc. • And also... Why we are here? When we are going to disappear? 3
  4. 4. 4
  5. 5. 5
  6. 6. 6
  7. 7. 7
  8. 8. 8
  9. 9. Not only muons hit the tank!!!! 9
  10. 10. Event reconstruction: S(1000m) Example Event (48°, E~70 EeV) Reconstruction procedure: χ²-method to fit angles (θ,φ) Likelihood method to fit a NKG-type function Fitting parameters core S(1000m) S(1000m) Slope β fixed 4 10 1000m
  11. 11. Fluorescence Reconstruction Electromagnetic energy - Fluorescence energy almost MC independent. SD tank EFD = finv x Eem 11
  12. 12. 12
  13. 13. 13
  14. 14. 14
  15. 15. 15
  16. 16. VEM: Vertical Equivalent Muon The Cherenkov light is measured in units of the signal produced by a: Vertical and Central Through-going Muon. 16
  17. 17. VEM: Vertical Equivalent Muon The Cherenkov light is measured in units of the signal produced by a: Vertical and Central Through-going Muon. We use: Atmospheric muons passing through the detector at a rate of 2500Hz 1 minute ~ 150000 events 17
  18. 18. Tipical FADC traces 150000 triggers 18
  19. 19. Tipical FADC traces 150000 triggers Pulse height - IpeakVEM 19
  20. 20. Tipical FADC traces 150000 triggers Pulse height - IpeakVEM Charge = Sum FADC(i) - QpeakVEM 20
  21. 21. Charge histograms and their relation to a VEM trigger threshold 0.2IpeakVEM For the sum of the 3 PMTs QpeakVEM = 1.09 VEM Individual PMTs QpeakVEM = 1.03 VEM 21
  22. 22. From simulations we can understand the charge histrograms structure Particles Flux Charge histograms 22
  23. 23. From simulations we can understand the charge histrograms structure Particles Flux Charge histograms 23
  24. 24. The calibration is done in 3 main steps: - The high voltage of each PMT is adjust to have approximately the same QpeakVEM in each PMT. - Each PMT has a single rate spectrum. Then we adjust the trigger thershold to have a single a rate of 100Hz at IpeakVEM = 150 ch. - This choice sets up each of the PMT to have approximately 50ch / IpeakVEM. - Continually perform a local calibration to determine the IpeakVEM in channels to adjust the electronic-level trigger. - Determine the value of QpeakVEM to high accuracy using charge histograms. 24
  25. 25. The calibration is done in 3 main steps: - The high voltage of each PMT is adjust to have approximately the same QpeakVEM in each PMT. - Each PMT has a single rate spectrum. Then we adjust the trigger thershold to have a single a rate of 100Hz at IpeakVEM = 150 ch. - This choice sets up each of the PMT to have approximately 50ch / IpeakVEM. - Continually perform a local calibration to determine the IpeakVEM in channels to adjust the electronic-level trigger. - Determine the value of QpeakVEM to high accuracy using charge histograms. 25
  26. 26. The calibration is done in 3 main steps: - The high voltage of each PMT is adjust to have approximately the same QpeakVEM in each PMT. - Each PMT has a single rate spectrum. Then we adjust the trigger thershold to have a single a rate of 100Hz at IpeakVEM = 150 ch. - This choice sets up each of the PMT to have approximately 50ch / IpeakVEM. - Continually perform a local calibration to determine the IpeakVEM in channels to adjust the electronic-level trigger. - Determine the value of QpeakVEM to high accuracy using charge histograms. 26
  27. 27. The calibration is done in 3 main steps: - The high voltage of each PMT is adjust to have approximately the same QpeakVEM in each PMT. - Each PMT has a single rate spectrum. Then we adjust the trigger thershold to have a single a rate of 100Hz at IpeakVEM = 150 ch. - This choice sets up each of the PMT to have approximately 50ch / IpeakVEM. - Continually perform a local calibration to determine the IpeakVEM in channels to adjust the electronic-level trigger. - Determine the value of QpeakVEM to high accuracy using charge histograms. 27
  28. 28. The calibration is done in 3 main steps: - The high voltage of each PMT is adjust to have approximately the same QpeakVEM in each PMT. - Each PMT has a single rate spectrum. Then we adjust the trigger thershold to have a single a rate of 100Hz at IpeakVEM = 150 ch. - This choice sets up each of the PMT to have approximately 50ch / IpeakVEM. - Continually perform a local calibration to determine the IpeakVEM in channels to adjust the electronic-level trigger. - Determine the value of QpeakVEM to high accuracy using charge histograms. 28
  29. 29. Information about Calibration that comes with each event Baseline Histogram 29
  30. 30. Information about Calibration that comes with each event Pulse Height Histogram 30
  31. 31. Information about Calibration that comes with each event Shape Histogram 31
  32. 32. Information about Calibration that comes with each event Charge individual PMT Histogram 32
  33. 33. Information about Calibration that comes with each event Charge sum of 3 PMTs Histogram 33
  34. 34. Signal [VEM peak] 34
  35. 35. 0 Inclined Showers( >60 ): The analysis of inclined events is very important because: - Increase the statistics,  ∈ (600,800), 30% more events. - Enlarge sky map: allows the study of clustering and anisotropy in an extended region of the sky. - EM component is absorbed in the atmosphere. Inclined showers are sensitive to the muonic component. - We can study composition, because the total number of muons depends on the energy and primary particle type. - Neutrino events may interact deep in the atmosphere. 35
  36. 36. 0 Inclined Showers( >60 ): The analysis of inclined events is very important because: - Increase the statistics,  ∈ (600,800), 30% more events. - Enlarge sky map: allows the study of clustering and anisotropy in an extended region of the sky. - EM component is absorbed in the atmosphere. Inclined showers are sensitive to the muonic component. - We can study composition, because the total number of muons depends on the energy and primary particle type. - Neutrino events may interact deep in the atmosphere. 36
  37. 37. 0 Inclined Showers( >60 ): The analysis of inclined events is very important because: - Increase the statistics,  ∈ (600,800), 30% more events. - Enlarge sky map: allows the study of clustering and anisotropy in an extended region of the sky. - EM component is absorbed in the atmosphere. Inclined showers are sensitive to the muonic component. - We can study composition, because the total number of muons depends on the energy and primary particle type. - Neutrino events may interact deep in the atmosphere. 37
  38. 38. 0 Inclined Showers( >60 ): The analysis of inclined events is very important because: - Increase the statistics,  ∈ (600,800), 30% more events. - Enlarge sky map: allows the study of clustering and anisotropy in an extended region of the sky. - EM component is absorbed in the atmosphere. Inclined showers are sensitive to the muonic component. - We can study composition, because the total number of muons depends on the energy and primary particle type. - Neutrino events may interact deep in the atmosphere. 38
  39. 39. 0 Inclined Showers( >60 ): The analysis of inclined events is very important because: - Increase the statistics,  ∈ (600,800), 30% more events. - Enlarge sky map: allows the study of clustering and anisotropy in an extended region of the sky. - EM component is absorbed in the atmosphere. Inclined showers are sensitive to the muonic component. - We can study composition, because the total number of muons depends on the energy and primary particle type. - Neutrino events may interact deep in the atmosphere. 39
  40. 40. 0 Inclined Showers( >60 ): - Inclined showers are all about muons! - Understand the tank response to inclined muons is crucial. - Up to now there is not specific measurements for inclined and individuals muons with high statistics. - We only have simulations! Which have some unknown parameters. 40
  41. 41. Muon Flux and Muon rate in a Pierre Auger Tank 70 deg. -> 1 Hz 80 deg. -> 0.04 Hz 41 85 deg. -> 0.001 Hz
  42. 42. Inclined Showers TODO LIST: - Charge histograms as a function of the zenit angle - Direct light (PMT balance) - Signal versus Track length - Measured the muon flux - Muon decay - Start Time variance - Check the simulations 42

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