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EAS Reconstruction with Cerenkov photons Ching-Cheng Hsu, Jan.29 2003 Ching-Cheng Hsu National Taiwan Univ. Dept of physics Feb. 13 2003 Shower Simulation.

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Presentation on theme: "EAS Reconstruction with Cerenkov photons Ching-Cheng Hsu, Jan.29 2003 Ching-Cheng Hsu National Taiwan Univ. Dept of physics Feb. 13 2003 Shower Simulation."— Presentation transcript:

1 EAS Reconstruction with Cerenkov photons Ching-Cheng Hsu, Jan.29 2003 Ching-Cheng Hsu National Taiwan Univ. Dept of physics Feb. 13 2003 Shower Simulation Reconstruction Algorithm Toy MC Study Summary

2 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 CORSIKA-> Reconstruction Air Shower Č photons CORSIKA telesim Read out Č photons and simple detector simulation photon weighting, detectors sampling Reconstruction E, shower axis Input card ?

3 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Detector configurations 4 m 2m 20m Corsika detector Our detector 40 X 50 detectors in a 4.5 x 5.0 km 2 area 20m

4 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Detection area Y X 10 km 5 km 4.5 km 10 km North West

5 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Detector Parameters Lens area : 4 m 2. Transmittance 0.95 Focal length : 43 cm Pixel angular Span: 0.5 degree PMT QE : 0.3 Spot size : 0.04 cm < pixel size 0.375 cm We have 40x40 pixels of PMT in a 15 cm x15 cm area

6 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Č Production Height Higher Energy Closer to the Ground 31-34 Km 10 14 eV 10 16 eV 10 18 eV Electron showers with new atmospheric model

7 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Photon density on the ground 10 18 eV 10 16 eV 10 14 eV Peak position 680 – 750 m

8 MINUIT: minimize χ2 to get x,y,θ,φ and E (x2, y2 ) N2. t2   N1, t1 (x1, y1) E, (x, y,θ,φ) Reconstruction Illustration Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003

9 Cerenkov photon density Double Gaussian + exponential decay Photon density Electron shower 10 14 eV We know N(E,  )

10 22 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 The Algorithm Within a polar angle 12  region, randomly pick one detector and choose another detector separated by 200 m distances to minimize the following    2 = (  1 - 0.13) 2 / 0.15 2 + (  2 -0.13) 2 / 0.15 2 + d 1 2 / 30 2 + d 2 2 /30 2 + [N 1 -N(E,  1 )] 2 / N 1 + [N 2 -N(E,  2 ] 2 / N 2 + (l 1 /c - l 2 /c+t 2 -t 1 ) 2 / 0.3 2

11 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Reconstruction CORSIKA data ΔxΔx ΔtΔt ΔθΔθ Er / Et 10 14 eV Detectors distance 200m

12 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Reconstruction CORSIKA data 10 16 eV Detectors distance 200m ΔxΔxΔtΔt ΔθΔθ Er / Et

13 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Study of Two Detector Performance with Toy MC 10 15 eV electron shower One p.e. threshold, no background Shower starts 30 km height Mirror area 1 m 2 Field of view 12 o Pixel angular span 1 o Vary the distance between the detectors with 100 m step

14 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Efficiency Within 2km, efficiency is flat. →

15 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 OK, near 1 The Mean Reconstructed Energy Ratio

16 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Reconstructed Augular Deviation 1 o can be achieved

17 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Summary We can reconstruct EAS with Č photons from Corsika data by two detectors. We can reconstruct EAS with Č photons from Corsika data by two detectors. The reconstruction method is simple and can be improved. The reconstruction method is simple and can be improved. The study done by a Toy MC indicates the detector separation of 3 o -4 o is optimal. The study done by a Toy MC indicates the detector separation of 3 o -4 o is optimal. Next Step: Next Step: Put in background and use pixel information for shower reconstruction. Put in background and use pixel information for shower reconstruction.

18 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Reconstruction by Toy MC 10 14 eV Δθ Er / Et ΔxΔx ΔtΔt

19 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Absolute Time difference in Two Detectors CORSIKA data 200 ns for separation distance 2km Hard for coincidence?

20 Ching-Cheng Hsu PSROC 2003, Feb. 12, 2003 Fit to 5 km Similar PDF parameters

21 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Difficulties of Simulation

22 Ching-Cheng Hsu PSROC 2003, Feb. 12, 2003 Difficulties of Simulation

23 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Difficulties of Simulation

24 Ching-Cheng Hsu PSROC 2003, Feb. 13, 2003 Difficulties of Simulation

25 Ching-Cheng Hsu PSROC 2003, Feb. 12, 2003 Difficulties of Simulation

26 Ching-Cheng Hsu PSROC 2003, Feb. 12, 2003 Difficulties of Simulation

27 Ching-Cheng Hsu PSROC 2003, Feb. 12, 2003 Difficulties of Simulation

28 Ching-Cheng Hsu PSROC 2003, Feb. 12, 2003 Difficulties of Simulation


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