Análisis de datos en KASCADE-Grande

Transcription

1 Análisis de datos en KASCADE-Grande Juan Carlos Arteaga-Velázquez for the KASCADE-Grande Collaboration Instituto de Física y Matemáticas Universidad Michoacana arteaga@ifm.umich.mx Morelia,Mich. Junio 2009

2 Análisis de datos en KASCADE-Grande Estructura de la plática 1) Introducción 2) Chubascos atmosféricos 3) El detector 4) Reconstrucción del chubasco 5) Dirección de arribo 6) Número de muones 7) Precisión de reconstrucción 8) El espectro de muones 9) Resumen Morelia,Mich. Junio 2009

3 1) Introduction : cosmic rays around the knee Direct detection Indirect detection through atmospheric air showers

4 2) Air showers

5 3) The detector

6 Energía Dirección arribo Composición Se interpretan datos en base a simulaciones de MC (chubascos + detector)

7 KASCADE-Grande (Karlsruhe Shower Core and array detector) E = ev KASCADE

8 KASCADE-Grande (Karlsruhe Shower Core and array detector) E = ev Grande array: Area: 0.5 km 2. Stations: 37 x 10m 2 plastic scintillator detectors. Average distance: 140 m. E range: ev. Trigger: 18 clusters of hexagonal shape. Rate: 0.5 Hz. EAS e/γ and µ components together.

9 The GRANDE Array The detector station Mixers, amplifiers, discriminators 16 plastic scintillator (NE102A) 80x80x4 cm 3 HV divider Steel box 16 high gain PMTs 4 low gain PMTs The DAQ 37 Stations of plastic scintillators 10 m m average distance 0.5 km 2 total surface Peak sensing ADC: Particle density range: 10 4 m.i.p./10m 2 TDC: 0.8 ns resolution

10 KASCADE-Grande (Karlsruhe Shower Core and array detector) E = ev 192 µ detectors distributed in 12 outer clusters. KASCADE shielded scintillators allow to measure µ component of EAS. (E µ > 230 MeV secθ)

11 The KASCADE Array 252 detectors 3.2 m 2 each 13 m distant 200 x 200 m 2 e/γ : liquid, 48 mm µ : plastic, 30 mm

12 4) EAS reconstruction Relevant EAS parameters obtained from combined LL-Chi 2 fit to energy deposits and arrival times. 1) Core position, arrival direction use Grande array data 2) Number of charged particles from Grande array data 3) Muon number obtained with KASCADE µ detectors 4) Electron number extracted from Grande and KASCADE µ detectors information.

13 5) Arrival direction From χ 2 minimization to measured arrival times: χ2 = Σ (T i data T i model - T i ) 2 / σ i 2 i Arrival time 1 st of N particles Minimum time uncertainty and fluctuations of T i.

14 Arrival direction of primary from χ 2 minimization to measured arrival times: χ2 = Σ (T i data T i model - T i ) 2 / σ i 2 i Where: T i model = r i n/c = [x i cosa + y i cosb + z i cosc]/c with: cos a = sin ϑ cos ϕ cos b = sin ϑ sin ϕ cos c = [1 cos 2 a cos 2 b] 1/2 σ i : Minimum time uncertainty (~ 2 ns) and fluctuations of T i. n

15 From χ 2 minimization to measured arrival times: χ2 = Σ (T i data T i model - T i ) 2 / σ i 2 i From Corsika

16 From χ 2 minimization to measured arrival times: χ2 = Σ (T i data T i model - T i ) 2 / σ i 2 i Parametrization used: T = (a 0 /N p ) (1 + r/a 1 ) q Dependence with primary, energy, θ z, N e and N µ.

17 T i (r), σ i (r) from MC simulations CORSIKA 6.307, QJSGET II. P+Fe, E = ev.

18 6) Muon number N µ from measured muon densities in KASCADE detectors: ρ µ (r) = N µ f(r) f(r) parameters from MC simulations: CORSIKA 6.307, QJSGET. P+Fe, E = ev. θ z = 22 0.

19 N µ from measured muon densities in KASCADE detectors: ρ µ (r) = N µ f(r) N µ = Σ n(r i ) / Σ [f(r i ) A i cos(θ z )]

20 7) Reconstruction accuracy Don t hurry up! first quality cuts Fiducial area: Octagon A 4 x 10 5 m 2 Avoid effect of missreconstructed core positions Fabiana

21 Quality cuts: θ < 40 o Octagon: A 4 x 10 5 m 2 N activated stations > 19 Successfully reconstructed N charged log 10 (N ch /8.5) > 2.9 log 10 (N e /4.2) -8.4/ < Age parameter <1.485 N µ N e clusters activated No DAQ and hardware problems Hit 7/7 > 0

22 KASCADE-Grande : Angular resolution

23 KASCADE-Grande : Muon number

24 KASCADE-Grande : Muon number

25 KASCADE-Grande : Trigger

26 7) Reconstruction accuracy Angular resolution MC data e e+µ

27 Electrons P+Fe Electrons and muons y x Total angular error (deg). MC data x

28 Shower front: KG data

29 Shower front: KG data

30 Muon number Mixed Mixed

31 Mixed Mixed

32 8) The muon spectra N µ corrected for systematics

33 8) The muon spectra KG Data: 3 years of observation N Tot = 26,453,284 Φ µ = n/[ t A Ω N µ ] After quality cuts: A 4 x 10 5 m 2 t 498 d N events = 81,593 N µ corrected for systematics

34 8) The muon spectra KG Data: 3 years of observation N Tot = 26,453,284 Φ µ = n/[ t A Ω N µ ] Poisson distribution n = (n) 1/2 N µ corrected for systematics

35 8) The muon spectra Differences between MC and exp. data increase with θ. Comparing experimental and simulated data For 50 o θ 70 o : Φ µ 20 %

36 9) Summary Different shower observables are used to study the primary cosmic ray. MC simulations are employed to study the performance of the detector and shower development. Selection cuts are important for the analysis of experimental data. Cuts take into account shower parameters, trigger, detectors, etc. MC data does not take describe satisfactory all experimental data.