CORSIKA: Extensive Air Shower Simulation · Stefan Klepser, DESY Zeuthen: CORSIKA 22/25 LPM-Effect...
Transcript of CORSIKA: Extensive Air Shower Simulation · Stefan Klepser, DESY Zeuthen: CORSIKA 22/25 LPM-Effect...
CORSIKA:Extensive Air Shower Simulation
Stefan Klepser
DESY Zeuthen,Humboldt-Universität zu Berlin
dec 2006
Stefan Klepser, DESY Zeuthen: CORSIKA 2/25
Outline
• CORSIKA basics– introduction– work flow– the code– steering a simulation
• Interaction Models
• CORSIKA in I3
• Special Effects ۻ– curved & upward option– LPM-Effect– ν-induced Showers
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Extensive Air Shower Basics
Energy flow:
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CORSIKA Task Flow
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The Corsika Code...
All code except interaction models & root output is in 1 fortran file corsika.F:
– 2 MB– 61882 lines– 11444 comment lines– 54 functions– 210 subroutines
234 lines / substructure
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Simulation: Features
• Input Features:
– Primary Particle Parameters:• Type: γ, p, He, O, Fe, μ, ν...• Energy: single or spectrum• Direction: single or area
– Surrounding Parameters:• Atmosphere• Earth‘s Magnetic Field• Detection height (multiples
possible)
– Simulation Parameters:• Interaction models• Thinning• Energy Thresholds• Curved Atmosphere Option• Upward Option• LPM, Preshower• Neutrino, Cherenkov Tracking
•
Stee
ring
file
optio
ns
Com
pilationoptions
Output Features:
– Secondary Particle Information:• Type: γ, p, He, O, Fe, μ, ...• Energy• Direction• Position• Time
– Longitudinal & Lateral Distributions:• Energy• Particle Number
– Statistical Collision Information• Energies• Number of Secondaries• Multiplicity
– Specials• Neutrinos• Cherenkov-Light• Fluorescence Light
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The Input File
run corsika
~ % cd $CORSIKA/run~ % corsika6502Linux_SIBYLL_
to get
DAT000001 (binary) or
on command line:
# yes, neccessaryfluka < input.inp > output.out
DAT000001.root
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Sketches of different showers...iron1014 eV
proton1014 eV
photon1014 eV
red = electrons, positrons, gammasgreen = muonsblue = hadrons
Energy cuts:0.1 MeV for e+-, gammas0.1 GeV for muons, hadrons
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Sketches of single components –proton shower
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Sketches of single components –photon shower
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Interaction models
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Electromagnetic Interactions: EGS4
• ‚EGS‘ = Electron Gamma Shower Code• ‚4‘ = 4-dimensional simulation• ALL known e+- and γ interactions are included:
– bremsstrahlung– ionisation– d-electrons– Bhabha & Moeller scattering– multiple scattering– annihilation– e+e- pair production– Compton effect– photo effect– Rayleigh scattering– Extended by the LPM-Effect (relevant in the atmosphere > 1018eV)
→ NO PROBLEM HERE!
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Hadronic Interactions
Energy ranges:
• resonance range
• intermediate range
• high-energy range
default„high“/„low“ energy
transition
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Recommended LE Models:
• FLUKA+ works best and fastest+ always updated due to commercial motivation (NASA, ...)- non-open source → non-transparent
• UrQMD (M. Bleicher et al.)+ real space-time-Simulation+ frequently enhanced- slower
Note: GHEISHA is not updated anymore!It should not be used any longer!
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Recommended HE Models:
• QGSJET-II+ highly sophisticated Pomeron-Pomeron coupling+ fits the data best- slow
• SIBYLL+ - different principle+ comparable performance+ faster
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Standard settings in I3 muon simulation(nov 2006)
• adopted from dCORSIKA (D. Chirkin):– LE interactions: GHEISHA– HE interactions: QGSJet01.c
→ WHY?
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CORSIKA in I3
• simulation doxygen:http://software.icecube.wisc.edu/SIMULATION/
• production homepage:http://icecube.wisc.edu/simulation/
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InIce CORSIKA in I3
• Module Flow:
I3Muxer → I3GeneratorUCR → I3PropagatorMMC → ...
readsin files
generatedw
ithstandalone
dCO
RSIKA
and propagatesthem
throughthe
planet
(byD
.Chirkin)
wrapper for the
javaprogram
mm
c,
propagatesm
uonsthrough
thedetector
(byD
.Chirkin)
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IceTop CORSIKA in I3
• Module Flow:
I3Muxer → I3CorsikaXX → I3ArrayShowerTracer → I3Romeo...
readsin plain
CO
RSIKA files
and putsthe
particlesin the
frame
(byP. N
ießen/ A. O
livas)
calculatesthe
tank signal for eachparticle
bythe
intersect of theparticle
trackw
iththe
tank
(byP. N
ießen)
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Special Effects
• Curved & Upward option
• LPM-Effect
• Neutrino-Induced Showers
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Curved & Upward optionsfor inclined showers (e.g. neutrino showers)
h
standard curved upward
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LPM-Effect
• ‚LPM‘ = Landau-Pomeranchuk-Migdal• effect on high energy gammas > 1018 eV• „The multiple Coulomb scattering angle exceeds
the [bremsstrahlung] emission cone, so theradiation intensity diminishes“
• That means: bremsstrahlung and pair productiondecreases with higher energy or denser air
→ high energy gamma showers get even deeper in the atmosphere
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Confusing HE showers...
UHE p-shower~ HE γ-shower!
→ some UHE Events couldhave beenphotons!
LPM
Preshower
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Neutrino-Induced Showers
• CORSIKA + HERWIG (O. Pisanti et al.) = ν-induced shower• Mostly horizontally possible (ν + air, mountain) → curved &
upward option!• Different signatures:
νe νe
N N* → shower
νe
N N* → shower
e→ shower
νμ
N N* → shower
μ→ NO shower
ντ
N N* → shower
τ→ decay → shower
doublebang
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Summary
• The talk was great• Everything is clear
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Resonance Range
All kinds of occuring resonances, well-measured in experiments, are taken into account:
PDG
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Intermediate Range
QCD String fragmentation processes:i) inelastic, with gluon radiation ii) elastic, diffraction dissociation
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High-Energy Range
• Hard Physics (high pt = „easy“): QCD → Minijet Production, ...
• Soft Physics (low pt = „difficult“): Gribov-Regge-Theory= Treating Parton Cascades as Quasi-Particles
→ POMERON (named after Isaak Yakovlevich Pomeranchuk)
= =
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QGSJET-II
(Sergej Ostapchenko)
Semi-hard processes: