Tunka 133 cosmic ray mass composition at 10 16 10 18 ev
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Tunka-133: Cosmic Ray Mass Composition at 10 16 – 10 18 eV. Vasily Prosin (SINP MSU) For the Tunka Collaboration. Tunka Collaboration.

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Tunka 133 cosmic ray mass composition at 10 16 10 18 ev
Tunka-133: Cosmic Ray Mass Composition at 1016 – 1018 eV

Vasily Prosin (SINP MSU)

For the Tunka Collaboration


Tunka collaboration
Tunka Collaboration

S.F. Beregnev, S.N. Epimakhov, N.N.Kalmykov, E.E.Korosteleva, N.I. Karpov, V.A.Kozhin, L.A.Kuzmichev, M.I.Panasyuk, E.G. Popova, V.V.Prosin, A.A.Silaev, A.A.Silaev(ju),

A.V.Skurikhin, L.G. Sveshnikova, I.V.Yashin

–Skobeltsyn Inst. of Nucl. Phys.of Lomonosov Moscow State Univ., Moscow, Russia;

N.M.Budnev, A.V. Dyachok, O.A. Chvalaev, O.A.Gress, A.V. Korobchenko,R.R. Mirgazov, L.V.Pan’kov, Yu.A.Semeney,A.V. Zagorodnikov

–Inst. of Applied Phys. of Irkutsk State Univ., Irkutsk, Russia;

B.K.Lubsandorzhiev, B.A. Shaibonov(ju)

–Inst. for Nucl. Res. of Russian Academy of Sciences, Moscow, Russia;

V.S.Ptuskin

–IZMIRAN, Troitsk, Moscow Region, Russia;

Ch.Spiering, R.Wischnewski

–DESY-Zeuthen, Zeuthen, Germany;

A. Chiavassa

–Dip. di Fisica Generale Universita' di Torino and INFN, Torino, Italy.

D. Besson, J. Snyder, M. Stockham

– Department of Physics and Astronomy, University of Kansas, USA


Tunka 133 update 2011
Tunka-133 (update 2011)


Corsika simulated lateral distributions and fitting function ldf
CORSIKA: Simulated lateral distributions and fitting function (LDF)

E0 ~ Q1750.93

LDF has a single variable parameter of shape - steepness: P=Q(100)/Q(200)

0 < R < 700 m

Q(R) = Qkn·exp((Rkn-R)·(1+3/(R+3))/R0)

Q(R) = Qkn·(Rkn/R)2.2

Qkn

R0 = 102.95-0.245·P [m]

Rkn = 109 - 24.5·(P-4) [m]

b = 4.84 - 2.83∙log10(6.5-P)

Rkn

1 - P=5.0 2 – P=4.1 3 – P=3.2

Q175

Q(R) = Q(200)·((R/200+1)/2)-b


An example of real shower of 1 6 03 20 10
An example of real shower of function (LDF)16.03.2010

The limits for distances used now to unify Xmax analysis for all energy range:

WDF

FWHM(400) – analysis

LDF

P – analysis


3 the new methods of analysis for high core distances
3. The function (LDF) new methods of analysis for high core distances

LDF

LDF steepness analysis


Experiment every event 7 133 pairs of records
EXPERIMENT: function (LDF)Every event = 7 – 133 pairs of records:

The primary data record for each Cherenkov light detector containes 1024 points of amplitude vs. time with the 5 ns time step:

  • Pulse selection

  • Apparatus distortions correction

  • Pulse waveform fitting

anode

dynode


Experiment
EXPERIMENT: function (LDF)

The main parameters determination – area (light flux)Qi, amplitudeAi, width FWHMiand front delay ti at 0.25Ai.

(The more accurate FWHM = τeff/1.24, τeff = Qi/Ai)

ti

FWHMi

anode

Ai

dynode


Corsika core location ldf and adf
CORSIKA: Core location – LDF and ADF function (LDF)

Core location: Amplitude – Distance Function (ADF),

ADF tail fit: A(R) = A(400)·((R/400+1)/2)-bA steepness: bA

LDF tail fit: Q(R) = Q(300)·((R/300+1)/2)-bQsteepness: bQ

bA > bQ


Accuracy of the eas core reconstruction
Accuracy of the EAS core reconstruction function (LDF)

For R< 450 m: ΔRcore ~ 10 m

For 450 m < R < 800 m: ΔRcore ~ 20 m for ADF method

and ΔRcore ~ 30 m for LDF method


Corsika eas cherenkov light front
CORSIKA: EAS Cherenkov light front function (LDF)

tfront = (R+200)2/S

Δθ < 0.5° for Nclusters > 4


Recalculation from cherenkov light flux q 200 to the primary energy e 0
Recalculation from Cherenkov light flux Q function (LDF)200tothe primary energy E0

E0 = A·Q200g

g = 0.94

CORSIKA simulation:

~ 500 protons

~ 500 iron

Zenith angles: 0°, 30°, 45°


Zenith angular distribution for e 0 2 10 16 ev
Zenith angular distribution for E function (LDF)0 > 2·1016 eV


Corsika x max reconstruction
CORSIKA: X function (LDF)max reconstruction

∆Xmax = 2767 - 3437∙log10(bA-2), g∙cm-2


Phenomenological approach experimental ldf steepness vs zenith angle for e 0 3 10 16 ev
PHENOMENOLOGICAL APPROACH: function (LDF)Experimental LDF steepness vs. zenith angle for E0 = 3·1016 eV

~3500 events: 16.4 < log10(E0/eV) < 16.5

cosθ ΔXmax = X0/cosθ – Xmax

X0 = 965 g·cm-2

<Xmax> = 570 g·cm-2 for E0 = 3·1016 eV


Phenomenology x max reconstruction
PHENOMENOLOGY: X function (LDF)max reconstruction

∆Xmax = 2870 – 3520∙log10(bA-2), g∙cm-2



Shower front
Shower front function (LDF)



Shower front1
Shower front function (LDF)


Plan function (LDF)

Lightdistribution

Shower front

Pulse width


Plan function (LDF)

Lightdistribution

Shower front

Pulse width


Plan function (LDF)

Lightdistribution

Shower front

Pulse width


anode function (LDF)

dynode


anode function (LDF)

dynode


anode function (LDF)

dinode


Experimental data
Experimental data function (LDF)

3 winter seasons 2009-2010, 2010-2011 and 2011-2012

165 clean moonless nights

~ 980 h of data acquisition with trigger rate ~ 2-3 Hz

~7 000 000 events

Zenith angle θ≤ 45°, Rcore < 450 m:

~ 170 000 events with E0 > 6·1015 eV – 100% efficiency

~ 62 000 events with E0 > 1016 eV

~ 590 events with E0 >1017 eV

Zenith angle θ≤ 45°, Rcore < 800 m:

~ 1800 events with E0 >1017 eV – 100% efficiency

~ 150 events with E0 > 3·1017 eV

~ 8 events with E0 >1018 eV


Mean depth of eas maximum x max g cm 2 preliminary
Mean Depth of EAS maximum function (LDF)Xmax g·cm-2PRELIMINARY



Mean logarithm of CR atomic number function (LDF)

Berezhko 2009

CRs from SNRs +

reacceleration +

Extragalactic CRs

Yakutsk

Experiment:

ATIC-2 (Panov et al. 2006)

JACEE (Asakimori et al. 1998)

KASKADE (QGSJET, SIBYLL)

(Hörandel 2005)

HiRes (QGSJET, SIBYLL)

(Abbasi et al. 2005)

CRs from SNRs +CRs from AGNs

Accurate determination of CR composition at ε= 1017- 1019 eV is needed

to find transition from galactic to extragalactic CR component


Conclusion
CONCLUSION function (LDF)

  • Primary mass composition changes from light (He) at the knee to heavy at 3·1016 eV

  • The mass composition is heavy till at least 1017 eV

  • More statistics is needed at the energy range 1017 – 1018 eV

  • PLANS

  • More statistics.

  • The new simulations.

  • Xmaxdistribution analysis.


Thank you function (LDF)!


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