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Primary Energy Reconstruction Method for Air Shower Array Experiments
Samvel Ter-Antonyan and Ali Fazely
Inverse Problem for All-particle energy spectrum
Event-by-event method Unfolding
01001 ),()()( dEEEWEFEF A
AAAA dESAEEFS )|,()()(
Advantage: general formulation
Solutions: a) regularized unfolding iterative algorithm [KASCADE Collaboration , Astropart.Phys. 24 (2005) 1]
b) parameterization of inverse problem + + a priory spectral info. [GAMMA Collaboration, Astropart.Phys. 28 (2007) 169]
Disadvantage:Pseudo solutions for elemental spectra and undefined systematic errors for unfolding algorithms (KASCADE). [S. Ter-Antonyan, Astropart.Phys. 28 (2007) 321]
Advantage: simplicity
Solution: analytical or numerical integration[J. Phys. G: Nucl. Part. Phys. 35 (2008) 115]
Disadvantage: ? The most experiments ignore the methodic errors.
A
AA EFEF )()(0
Energy estimator: 10 EE
Event-by-event analysis
),,,( cossNNe [GAMMA_09]
This work{
)cos,,( 125 S
11250 },,{ SE [ICETOP_09]
01001 ),,()()( dEAEEWEFEF
is ill-posed problem for F(E0) due to A H, He, … Fe
Redefinition of inverse problem:
a priori: ,~)( 00 EEF =2.9 0.25 for 1 PeV E0 < 500 PeV
Let ))(|)(),((L),,( 0001 ELnEEAEEW
and )(1/)( 0010 EEEE and bEaLnE )()( 00
?),,( NNe [KASCADE-GRANDE]
2
)1(exp)()(
~ 221
10
EFEF , for , - constant
where
2.0001 )()( aEE , and |a|<< 0.1
Solution for primary spectrum
Spectral errors:
2
2222
1)1()1(~
~
F
F
F
F
Statistic Errors Methodic Errors
2
)1(exp)()(
~ 221
10
EFEF 2%
Multi-parametric energy estimator for ICETOP Array:
6
54
12532
11
cos
cosaa
aSa
aaE
5
A
iiA
i E
EE
)(
)lnln(
02x
2,1,,02
i=1,…104, AH, He, O, Fe
min{2(a1,a2,…a6,(Ei)| E0,i)}
,)(
refref r
rfSrS
CORSIKA EAS SIMULATION+
ICETOP DETECTOR RESPONSE+
LDF RECONSTRUCTION
if
then
Expected biases and uncertainties of primary energy
<Ln(
E 1/E 0)>
Log(E0/GeV)
GAMMA ExperimentICETOP
Log(E0/GeV)
(Ln
(E1/
E 0))
Distribution of errors (~ Gaussian)
Verification of method
Primary energy spectra for p, He, O, Fe from GAMMA Experiment data [GAMMA Collaboration, Astropart.Phys. 28 (2007) 169]
Expected reconstructedall-particle spectrum for ICETOP
Expected (red symbols) all-particle spectrumfor ICETOP