Atmospheric shower simulation studies with CORSIKA ARISTOTLE - - PowerPoint PPT Presentation

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Atmospheric shower simulation studies with CORSIKA ARISTOTLE - - PowerPoint PPT Presentation

Nov 05, 2023 384 likes •610 views

Atmospheric shower simulation studies with CORSIKA ARISTOTLE UNIVERSITY OF THESSALONIKI Physics Department Atreidis George High energy gamma ray astronomy at 100 GeV - 100 TeV High energy gamma rays photons. Coming from a distant source

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Atmospheric shower simulation studies with CORSIKA

Physics Department Atreidis George ARISTOTLE UNIVERSITY OF THESSALONIKI

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High energy gamma ray astronomy at 100 GeV - 100 TeV

High energy gamma rays photons.

Coming from a distant source

  • utside the Earth.

Energies beyond those achievable in man-made accelerators.

When a VHE gamma-ray enters the Earth's atmosphere, it generates an atmospheric shower.

 secondary charged particles  Cherenkov light

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Detection – Air showers

interaction atmospheric shower Cherenkov photons air shower telescopes (AST)

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Primary particle – gamma ray photon.

Three sets of showers. Every set consists of 10 showers.

The primary particle energy is. First set  10 TeV Second set  40 TeV Third set  70 TeV

Zenith angle  20 deg.

Azimuth angle  from -180 to 180 deg.

Observation level  110m above sea level.

The results are average values for each set of shower.

Atmospheric shower simulation with Corsika

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Coordinate system in Corsika

Θ  Zenith angle. Φ  Azimuth angle.

  • The positive x-axis points to the

magnetic North.

  • The positive y-axis points to

the West.

  • The z axis points upwards.
  • The origin is located at sea level.

The coordinates in CORSIKA are defined with respect to a Cartesian coordinate system.

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Gamma particles distribution

Gamma particles distribution

0,00E+00 4,00E+03 8,00E+03 1,20E+04 1,60E+04 2,00E+04 200 400 600 800 1000 Depth (g/cm**2) No of gamma particles 10 TeV

Starting point. The top of the atmosphere. Observation level. 110 m above sea level. Shower maximum at a depth of 420 g/cm2.

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Gamma particles distribution

0,00E+00 4,00E+04 8,00E+04 1,20E+05 200 400 600 800 1000 Depth (g/cm**2) No of gamma particles 10 TeV 40 TeV 70 TeV

Gamma particles distribution

 Big primary energy  more gamma particles.  Shower maximum  goes deeper.

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Positrons distribution

Positrons distribution

4000 8000 12000 16000 20000 200 400 600 800 1000 Depth (g/cm**2) No of positrons 10 TeV 40 TeV 70 TeV

 Big primary energy  more positrons.  Shower maximum  goes deeper.

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Electrons distribution

Electrons distribution

5000 10000 15000 20000 25000 200 400 600 800 1000 Depth (g/cm**2) No of electrons 10 TeV 40 TeV 70 TeV

 Big primary energy  more electrons.  Shower maximum  goes deeper.

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Lateral electron density

Lateral electron density

0,00E+00 2,00E-05 4,00E-05 6,00E-05 8,00E-05 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 Distance from core (cm) Electron density 10 TeV 40 TeV 70 TeV

at observation level

for the three primary energies the density is reduced about 80% at a distance of 14 m from the core

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Shower energy distribution

 Continuing reduction in the shower energy.  Energy loss  energy deposit into air.

Longitudinal energy distribution

0,00E+00 2,50E+03 5,00E+03 7,50E+03 1,00E+04 1,25E+04 200 400 600 800 1000 Depth g/cm**2 Energy (GeV) 10 TeV

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Energy deposit into air

Energy deposit (primary particle 70 TeV)

400 800 1200 1600 2000 200 400 600 800 1000 Depth (g/cm**2) Energy (GeV) gammas e+-ioniz e+-cut

ionization energy deposit cut energy for electrons – positrons (0.15 GeV) cut energy for gamma particles (0.15GeV)

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Number of charged particles at observation level

Observation level 110 m above sea level

Number of electrons - positrons at observation level

50 100 150 200 250 300 1 2 3 Energy (TeV) No of electrons No of positrons

Ne>Np More primary energy  more particles at observation level.

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 Number of Cherenkov detectors in x direction10  Number of Cherenkov detectors in y direction 8  Distance of detectors in x direction1200 cm  Distance of detectors in y direction 1500 cm  Length of the detector in x direction 80 cm  Length of the detector in y direction 50 cm.

Locations of Cherenkov detectors in the simulation

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Production of Cherenkov photons per 20 g/cm**2)

0,00E+00 4,00E+07 8,00E+07 1,20E+08 1,60E+08 200 400 600 800 1000 1200 Depth (g/cm**2) No of Cherenkov photons Primary particle 70 TeV

Production of Cherenkov photons per 20g/cm2

More Cherenkov photons at the shower maximum. Starting point. The top of the atmosphere. Observation level. 110 m above sea level.

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Total production of Cherenkov photons

 The Cherenkov photons generated at all depths reach the observation level.  At great depths the number of Cherenkov photons created are small, so the total number tends to become stable.

Cherenkov photons distribution

0,00E+00 1,00E+09 2,00E+09 3,00E+09 200 400 600 800 1000 1200 Depth (g/cm**2) No of Cherenkov photons 10 TeV 40 TeV 70 TeV

  • bservation

level

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Total Cherenkov photons - energy

0,00E+00 1,00E+09 2,00E+09 3,00E+09 10 20 30 40 50 60 70 80 Primary particle energy No of Cherenkov photons Cherenkov

Increase Cherenkov photons with energy

  • Number of Cherenkov photons arriving at the observation level.

 The increase in the Cherenkov photons in connection with the energy

  • f the primary particle is almost linear.
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Experiments in High Energy Gamma Ray Astronomy

H.E.S.S. experiment

MAGIC experiment

VERITAS experiment Telescope arrays for the detection of Cherenkov light

 Energies from 100GeV to 100TeV.  Located in Namibia, near the Gamsberg mountain.  Mirror surface 236m2.  Located in La Palma, one of the Canarian islands.  Located in southern Arizona of the USA.  Energies >100GeV.  Energies from 50GeV to 50TeV.  An array of four 12m optical reflectors.

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New Experiment - CTA

Location

Three telescope types

Telescopes distribution

 Four 24 m telescopes with 5o field-of-view.  23 telescopes of 12 m diameter with 8o field-of-view.  32 telescopes of 7 m diameter with a 10o field-of-view.

Cost

 Not yet determined.  The telescopes are distributed over 3 km2 on the ground.  The effective collection area of the array is considerably larger than this at energies beyond 10 TeV. Array layout has a nominal construction cost of 80 M€ and meets the main design goals of CTA.

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Conclusions

The observation level should be lower. So The detectors should be extended more widely.

The high-energy range above 10TeV

Two implementation options

either a large number

  • f small telescopes
  • r a smaller number
  • f larger telescopes

For very high primary particle energy ~100TeV the maximum of the shower goes deeper and the Cherenkov light reaches its ultimate intensity at about 800 g/cm2 or ~2 km in altitude.

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Thank you for your time