COMPARISON OF EAS SIMULATION RESULTS USING CORSIKA CODE ... · COMPARISON OF EAS SIMULATION RESULTS USING CORSIKA CODE FOR DIFFERENT H.E. INTERACTION MODELS Chabin Thakuria and K

CRIS-2010

COMPARISON OF EAS SIMULATION

RESULTS USING CORSIKA CODE FOR

DIFFERENT H.E. INTERACTION

MODELS

Chabin Thakuria and K. Boruah

Dept. of Physics, Gauhati University, Assam, INDIA

15th Sep, 2010

Chabin Thakuria and K. Boruah COMPARISON OF EAS SIMULATION RESULTS USING CORSIKA

Out line of the talk CRIS-2010

Introduction

Primary Energy Spectra

Need for Simulation

Monte-Carlo & CORSIKA

About Monte Carlo Method

CORSIKA

Hadronic Interaction Models

Hadronic Interaction Models

Method

Result

Discussion


Primary Energy Spetra


Primary Energy Spectra CRIS-2010

1 Count-rate for cosmic ray of energy 1011eV is one countper m2 per second , where

2 at knee 4x1015eV is one count per m2 per year whereas

3 at ankle 5x1018eV is one count per km2 per year .

Hence Cosmic Rays of energy above 1014eV, because of verylow flux, can be studied indirectly by detecting secondaryparticles produced in the atmosphere using ground basedparticle detector array.




















Need for Simulation CRIS-2010

Also, to study and analyse Cosmic Rays

above 1PeV, one has to rely heavily on

Monte-Carlo Simulation models.

These theoretical models are developed

based on high energy particle interaction

characteristics derived mostly from

accelerator data.


Need for Simulation CRIS-2010

Also, to study and analyse Cosmic Rays

above 1PeV, one has to rely heavily on

Monte-Carlo Simulation models.

These theoretical models are developed

based on high energy particle interaction

characteristics derived mostly from

accelerator data.


Monte Carlo Method CRIS-2010

The Monte Carlo method provides approx.

solutions to a variety of mathematical

problems by performing statistical sampling

of experiments on a computer.

In this method computer generated pseudo

numbers are used to simulate a physical

process, which is divided into step by step

procedures.



The Monte Carlo method provides approx.

solutions to a variety of mathematical

problems by performing statistical sampling

of experiments on a computer.

In this method computer generated pseudo

numbers are used to simulate a physical

process, which is divided into step by step

procedures.



Using a known probability distribution of the

physical process at every step, the outcome

is determined using random numbers. Thus

in Monte Carlo simulation one generates

many virtual or artificial events according to

model selected with particular choices.




These events may then be statistically analyzed toyield real observable parameters and compared withthe existing real data.

This method applies to problems with noprobabilistic content as well as those with inherentprobabilistic structure.










About CORSIKA CRIS-2010

CORSIKA (COsmic Ray SImulations for KAscade)is a detailed Monte Carlo program to study the 4-Devolution and properties of extensive air showers inthe atmosphere.

It was developed to perform simulations for theKASCADE experiment at Karlsruhe in Germany.

Now various features of this versatile code isexploited by scientific community around the globe.













The CORSIKA program allows simulatinginteractions and decays of nuclei, hadrons,muons, electrons, and photons in theatmosphere up to energies of some 1020eV.

It gives type, energy, location, direction, andarrival times of all secondary particles that arecreated in an air shower and pass a selectedobservation level.



The CORSIKA program allows simulatinginteractions and decays of nuclei, hadrons,muons, electrons, and photons in theatmosphere up to energies of some 1020eV.

It gives type, energy, location, direction, andarrival times of all secondary particles that arecreated in an air shower and pass a selectedobservation level.



CORSIKA basically consists of 4 parts.

The first part is a general program framehandling the input and output, performingdecay of unstable particles, and tracking of theparticles taking into account ionization energyloss and deflection by multiple scattering andthe Earth’s magnetic field.




The second part treats the hadronic interactionsof nuclei and hadrons with the air nuclei athigher energies.

The third part simulates the hadronicinteractions at lower energies, and,

The fourth part describes transport andinteraction of electrons, positrons, and photons.















CORSIKA contains several models for the latterthree program parts that may be activatedoptionally with varying precision of thesimulation and consumption of CPU time.High-energy hadronic interactions may betreated by one of the models:



1 DPMJET (Dual Parton Model with JETs)2 EPOS (Electron Positron Scattering)3 NEXUS (NEXt generation Unified Scattering approach)4 QGSJET (Quark-Gluon String model with JETs)5 SIBYLL(QCD Based mini jet model)6 VENUS (Very Energetic NUclear Scattering )7 FLUKA (FLUctuating KAscade)8 GHEISHA (Gamma Hadron Electron Interaction SHower

code)9 UrQMD (Ultra relativistic Quantum Molecular

Dynamics)



1 DPMJET (Dual Parton Model with JETs)2 EPOS (Electron Positron Scattering)3 NEXUS (NEXt generation Unified Scattering approach)4 QGSJET (Quark-Gluon String model with JETs)5 SIBYLL(QCD Based mini jet model)6 VENUS (Very Energetic NUclear Scattering )7 FLUKA (FLUctuating KAscade)8 GHEISHA (Gamma Hadron Electron Interaction SHower

code)9 UrQMD (Ultra relativistic Quantum Molecular

Dynamics)


Interaction Model CRIS-2010

QGSJET...

Quark Gluon String with JETs is the mostsuccessful model describing the HE hadronicinteraction. This model offered relatively easyapproach to the simulation of cosmic rayinteractions at higher energies, as well asensured a good agreement to the acceleratordata at lower energies.



QGSJET...

In this model the appropriate cross sections for the inelasticinteraction between hadrons i and j are calculated using theexpression

χij(s, b) = χsij(s, b) + χh

ij(s, b)

where χsij(s, b) and χh

ij(s, b) represent the soft and semihardpomerons respectively. s is the centre of mass energy and b isthe impact parameter.



QGSJET...

The total cross section in this model is given by the formula

σtij(s) = 1

eij

∫

d2b[

1 − exp{

eij(χsij(s, b) + χh

ij(s, b))}]

where eij is the so-called shower enhancement co-efficient, forpp interactions epp = 1.5.



DPMJET...

Dual Parton Model with JETs is based on thetwo components Dual Parton Model andcontains multiple soft chains as well as multipleminijets.It relies on the Gribov-Regge theoryand the interaction is described by multiPomeron exchange.



DPMJET...

The total cross section in this model is given by the formula

σtij(b, s) = 4π

∫ inf

0 bdb [1 − exp(χij(s, b)]

where χij(s, b) represents total Pomeron in this model.



EPOS...

EPOS is a simple model where an exchange ofa parton ladder between the two hadrons can berelated to high energy hadron-hadroninteraction.

According to this model, parton ladder containstwo parts where the hard part describes theparton-parton hard scattering, while the softpart is a purely phenomenological object,parameterized in Regge pole fashion.



EPOS...

EPOS is a simple model where an exchange ofa parton ladder between the two hadrons can berelated to high energy hadron-hadroninteraction.

According to this model, parton ladder containstwo parts where the hard part describes theparton-parton hard scattering, while the softpart is a purely phenomenological object,parameterized in Regge pole fashion.



EPOS...

EPOS is a consistent quantum mechanicalmultiple scattering approach based on partonsand strings, where cross sections and theparticle production are calculated consistently,taking into account of energy conservation inboth cases


Method CRIS-2010

Method

To study the different shower parameters due tochange in hadronic interaction model, we havegenerated extensive air showers using CORSIKAsimulation with six hadronic interaction models.Here we have considered two primary masses(proton and iron) and four primary energies(1014eV, 1015eV, 1016eV and 1017eV). There arealtogether 46 sets of events with 1000 showerseach.


Method CRIS-2010

1 Simulation is performed considering only the verticalshowers at the average sea level .

2 THIN options are selected for flat horizontal detector.3 The relevant data are extracted from the output DATA

files using inbuilt FORTRAN program.4 The extracted data are then analysed using simple C++

program in the ROOT environment.


Method CRIS-2010






Method CRIS-2010






Method CRIS-2010






Method CRIS-2010






Result CRIS-2010

No.of Muon Vs No. of Electron


Result CRIS-2010

Findings

1 It is observed that for all the models iron primary showersproduce greater no. of muons as compared to thatproduced by proton primary showers

2 The model dependence of the parameter< Nµ > isstudied by calculating Merit Factor (MF)for eachmodel(M) compared to QGSJET,

MF=<Nµ(M)>−<Nµ(Q)>√σ2

M+σ2

Q

3 The values of MF for each case found to be < 0.1.Thisshows that there is no significant differences.


Result CRIS-2010

Findings

1 It is observed that for all the models iron primary showersproduce greater no. of muons as compared to thatproduced by proton primary showers

2 The model dependence of the parameter< Nµ > isstudied by calculating Merit Factor (MF)for eachmodel(M) compared to QGSJET,

MF=<Nµ(M)>−<Nµ(Q)>√σ2

M+σ2

Q

3 The values of MF for each case found to be < 0.1.Thisshows that there is no significant differences.


Result CRIS-2010

Muon no divided by Energy Vs Energy


Result CRIS-2010

Muon no divided by Energy Vs Energy


Result CRIS-2010

Findings

1 The EPOS and VENUS curves are flatter

2 Both the curves have significantly higher values than thatpredicted by the DPMJET and SYBILL.

3 Predictions by the QGSJET01 and QGSII have the valuesin between these values.

4 Slope of the curves for DPMJET, SYBILL, QGSJET01and QGSII are almost equal.

5 Relative differences between for example epos-protoncurve and the dpmjet-proton curve increases graduallywith energy from about 10 % at 1014eV to about 33 % at1017eV


Result CRIS-2010

Findings







Result CRIS-2010

Findings







Result CRIS-2010

Findings







Result CRIS-2010

Findings







Result CRIS-2010

Findings







Result CRIS-2010

Depth of Shower maximum Vs Energy


Result CRIS-2010

Findings

1 It is observed that irrespective of High Energy HadronicInteraction Models, the experimental data fall in betweenthe iron and proton curves as expected.


Discussion CRIS-2010

Discussion1 So far depth of shower maximum and muon Vs electron

number is considered, all the models show consitancyamong themselves.

2 But when we consider ratio of muon to primary energy,SIBYLL and EPOS gives significantly higher valuescompared to that obtained by the rest of the models.

3 This parameter may be used to study model dependenceat higher energy.














To Be Done.. CRIS-2010

Simulation to be done for higher energies.Study Zenith angle dependence

To Find sensitiveparameter

Observablessensitive to model

Viable StatisticalTests

Low EnergySubroutines

To comparedifferent lowenergy subroutines

Compare diff.cross sectionpredictions


Thank You.. CRIS-2010

T HANK YOUFOR ATTENTION


Documents

COMPARISON OF EAS SIMULATION RESULTS USING CORSIKA CODE ... · COMPARISON OF EAS SIMULATION RESULTS USING CORSIKA CODE FOR DIFFERENT H.E. INTERACTION MODELS Chabin Thakuria and K