1. The KASCADE-Grande Experiment: an Overview Andrea Chiavassa Universita’ di Torino for the KASCADE-Grande Collaboration

2. Motivation for measurements 10 16 -10 18 eV - test of hadronic interaction models

3. Detector Detected EAS component Detection Technique Detector area (m 2 ) Grande Charged particles Plastic Scintillators 37x10 Piccolo Charged particles Plastic Scintillators 8x10 KASCADE array e/  Electrons,  Liquid Scintillators 490 KASCADE array  Muons (E  th =230 MeV) (E  th =230 MeV) Plastic Scintillators 622 MTD Muons (Tracking) (E  th =800 MeV) Streamer Tubes 4x128 MWPCs/LSTsMuons (E  th =2.4 GeV) Multiwire Proportional Chambers 3x129 LOPES 30 Radio Radio Antennas (40-80 MHz) KASCADE-Grande @Forschungszentrum Karlsruhe

4. Grande 37 Stations of plastic scintillators 10 m 2 each 140 m average distance 0.5 Km 2 total surface 18 cluster 7/7 →  0.5 Hz → sent to KASCADE array detectors. Piccolo: fast trigger for the  tracking detectors

5. KASCADE-Grande Trigger efficiency in a fiducial area of 0.28 km 2 Including reconstruction cuts  100% reached at 2x10 16 eV or 10 6 Shower Size Hydrogen Iron All Elements Hydrogen Iron All Elements

6. KASCADE-Grande observables Shower core and arrival direction –Grande array Shower Size (N ch number of charged particles) –Grande array Fit NKG like ldf  Size (E  >230 MeV) –KASCADE array  detectors Fit Lagutin Function  density (E  >2400 MeV) –MWPC  density & direction (E  >800 MeV) –Streamer Tubes

7. Single Event

8. The resolution of the Grande array is obtained comparing the Grande event reconstruction with the one of the KASCADE array. Similar results are obtained reconstructing simulated events. Covering a wider shower size range and the whole detector area.

9. In each Shower size bin we obtain the distribution of the difference between the arrival directions measured by the Grande and by the KASCADE arrays Fitting a Rayleigh distribution the angular resolution of the Grande array is obtained  <0.7°  arrival direction ( ) Log N ch  = arccos(cos(  K )*cos(  G )+sin(  K )*sin(  G )+cos(  K -  G ))

10. core position resolution   5 m  core position (m) ( Log N ch

11. In each Shower Size bin we obtain the distribution of the difference between the Shower Size determined by the KASCADE and the Grande arrays (N ch,G -N ch, K )/N ch,K events

12. Grande Shower Size reconstruction accuracy ≤ 20%. Shower Size systematic difference with KASCADE <5% Log N ch

13. Lateral distributions of charged particles showing the good performance of the array 0 ° <  <18 °

14. Unfolding of 2-Dimensional shower size spectra, in different bin of zenith angle, will allow studies of energy & composition → still improvements in systematics needed → higher statistics E>10 17 eV  4300 events

15. Way to all particle Energy Spectrum: 1) Constant Intensity Cut Method (N ch or N  ) 1)Integral spectra measured in different bins of zenith angle 2) For a given I(>N X ) → N X (  ) Log N ch Integral Flux I(>N ch ) 3) Get Attenuation Curves

16. A first study of the systematic (N  ) uncertainties has been performed For E  10 17 eV →  E  22% Energy Spectrum measurements starting from different observables. Cross checks & Systematics 5) N ch,  (  ref ) is converted to primary energy Influence of: interaction models, MC statistics, slope used in the simulation 4) N ch,  (  ) → N ch,  (  ref )

17. Way to all particle Energy Spectrum: 2) Energy reconstruction by S(500) S(500) chosen as energy estimator Event by event determination of S(500) Correction to a reference angle S(500) is converted to primary energy

18. Way to all particle Energy Spectrum: 3) Primary energy estimated event by event N ch (or N  ) as primary energy estimator Log(N ch /N  ) as mass and shower fluctuation estimator From the bin to bin fluctuations Uncertainty ≤15% for E>10 16 eV from the ratio of reconstructed/true flux: systematic difference (different primaries) 10 16 eV log 10 (E)=a(k)  log 10 (N ch )+b(k) k=f(N ch /N ,N ch ) HFe original reconstructed Log E(GeV) Number of Events

19. First Results from KASCADE-Grande (ICRC 2007) Limits obtained with  1/3 of the available statistics are already significative. KASCADE-Grande results will play a relevant role in the evaluation of the anistropies in the knee region. Anisotropy

20. Conclusions KASCADE-Grande is measuring in the 10- 1000 PeV energy range since January 2004 Experiment performances: –angular resolution <0.7° –core resolution  5m –Shower size resolution ≤ 20% Energy Spectrum and Primary composition studies are on the way