Date post: | 01-Jul-2015 |
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Tank Calibration Pierre Auger Observatory
Gonzalo Rodriguez Universidad de Santiago de Compostela
Astroparticle groupfor the Pierre Auger Collaboration
Trasgo Project
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• 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.
Pierre Auger Observatory research goals
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• 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?
Pierre Auger Observatory research goals
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Not only muons hit the tank!!!!
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Event reconstruction: S(1000m)
S(1000m)S(1000m)
1000m1000m
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)
Slope β fixed
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Fluorescence Reconstruction
SD tank
- Fluorescence energy almost MC independent.
EFD
= finv
x Eem
Electromagnetic energy
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VEM: Vertical Equivalent MuonThe Cherenkov light is measured in units of the signal produced by a: Vertical and Central Through-going Muon.
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VEM: Vertical Equivalent MuonThe 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 2500Hz1 minute ~ 150000 events
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Tipical FADC traces150000 triggers
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Tipical FADC traces150000 triggers
Pulse height - Ipeak
VEM
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Tipical FADC traces150000 triggers
Pulse height - Ipeak
VEM
Charge = Sum FADC(i) - Qpeak
VEM
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Charge histograms and their relation to a VEM trigger threshold 0.2Ipeak
VEM
For the sum of the 3 PMTs Qpeak
VEM = 1.09 VEM
Individual PMTsQpeak
VEM = 1.03 VEM
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From simulations we can understand the charge histrograms structure
Particles Flux Charge histograms
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From simulations we can understand the charge histrograms structure
Particles Flux Charge histograms
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The calibration is done in 3 main steps:
- The high voltage of each PMT is adjust to have approximately the same Qpeak
VEM 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 Ipeak
VEM = 150 ch.
- This choice sets up each of the PMT to have approximately 50ch / Ipeak
VEM.
- Continually perform a local calibration to determine the Ipeak
VEM in
channels to adjust the electronic-level trigger.
- Determine the value of Qpeak
VEM to high accuracy using charge
histograms.
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The calibration is done in 3 main steps:
- The high voltage of each PMT is adjust to have approximately the same Qpeak
VEM 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 Ipeak
VEM = 150 ch.
- This choice sets up each of the PMT to have approximately 50ch / Ipeak
VEM.
- Continually perform a local calibration to determine the Ipeak
VEM in
channels to adjust the electronic-level trigger.
- Determine the value of Qpeak
VEM to high accuracy using charge
histograms.
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The calibration is done in 3 main steps:
- The high voltage of each PMT is adjust to have approximately the same Qpeak
VEM 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 Ipeak
VEM = 150 ch.
- This choice sets up each of the PMT to have approximately 50ch / Ipeak
VEM.
- Continually perform a local calibration to determine the Ipeak
VEM in
channels to adjust the electronic-level trigger.
- Determine the value of Qpeak
VEM to high accuracy using charge
histograms.
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The calibration is done in 3 main steps:
- The high voltage of each PMT is adjust to have approximately the same Qpeak
VEM 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 Ipeak
VEM = 150 ch.
- This choice sets up each of the PMT to have approximately 50ch / Ipeak
VEM.
- Continually perform a local calibration to determine the Ipeak
VEM in
channels to adjust the electronic-level trigger.
- Determine the value of Qpeak
VEM to high accuracy using charge
histograms.
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The calibration is done in 3 main steps:
- The high voltage of each PMT is adjust to have approximately the same Qpeak
VEM 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 Ipeak
VEM = 150 ch.
- This choice sets up each of the PMT to have approximately 50ch / Ipeak
VEM.
- Continually perform a local calibration to determine the Ipeak
VEM in
channels to adjust the electronic-level trigger.
- Determine the value of Qpeak
VEM to high accuracy using charge
histograms.
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Information about Calibration that comes with each event
Baseline Histogram
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Information about Calibration that comes with each event
Pulse Height Histogram
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Information about Calibration that comes with each event
Shape Histogram
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Information about Calibration that comes with each event
Charge individual PMT Histogram
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Information about Calibration that comes with each event
Charge sum of 3 PMTs Histogram
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Sig
nal
[V
EM
pea
k]
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Inclined Showers( >600):
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.
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Inclined Showers( >600):
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.
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Inclined Showers( >600):
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.
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Inclined Showers( >600):
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.
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Inclined Showers( >600):
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.
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Inclined Showers( >600): - 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.
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Muon Flux and Muon rate in a Pierre Auger Tank
70 deg. -> 1 Hz80 deg. -> 0.04 Hz85 deg. -> 0.001 Hz
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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