The KASCADE-Grande Experiment: an Overview

1
The KASCADE-Grande Experiment an Overview

• Andrea Chiavassa
• Universita di Torino
• for the KASCADE-Grande Collaboration

2
Motivation for measurements 1016-1018 eV

• test of hadronic
• interaction models

3
KASCADE-Grande _at_Forschungszentrum Karlsruhe
Detector Detected EAS component Detection Technique Detector area (m2)
Grande Charged particles Plastic Scintillators 37x10
Piccolo Charged particles Plastic Scintillators 8x10
KASCADE array e/g Electrons, g Liquid Scintillators 490
KASCADE array m Muons (Emth230 MeV) Plastic Scintillators 622
MTD Muons (Tracking) (Emth800 MeV) Streamer Tubes 4x128
MWPCs/LSTs Muons (Emth2.4 GeV) Multiwire Proportional Chambers 3x129
LOPES 30 Radio Radio Antennas (40-80 MHz)  
4
Grande 37 Stations of plastic scintillators 10 m2
each 140 m average distance 0.5 Km2 total
surface 18 cluster 7/7 ? ?0.5 Hz ? sent to
KASCADE array detectors. Piccolo fast trigger
for the m tracking detectors
5
KASCADE-Grande Trigger efficiency in a fiducial
area of 0.28 km2 Including reconstruction
cuts ?100 reached at 2x1016 eV or 106 Shower Size
Hydrogen Iron All Elements
Hydrogen Iron All Elements
6
KASCADE-Grande observables

• Shower core and arrival direction
• Grande array
• Shower Size (Nch number of charged particles)
• Grande array
• Fit NKG like ldf
• m Size (Emgt230 MeV)
• KASCADE array m detectors
• Fit Lagutin Function
• m density (Emgt2400 MeV)
• MWPC
• m density direction (Emgt800 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
DY arccos(cos(qK)cos(qG)sin(qK)sin(qG)cos(FK
-FG))
D arrival direction (
)

• Fitting a Rayleigh distribution
• the angular resolution of
• the Grande array is obtained
• lt0.7

Log Nch
10
(
s core position (m)
core position resolution s ? 5 m
Log Nch
11
events
In each Shower Size bin we obtain the
distribution of the difference between the Shower
Size determined by the KASCADE and the Grande
arrays
(Nch,G-Nch,K)/Nch,K
12
Grande Shower Size reconstruction accuracy 20.
Log Nch
Shower Size systematic difference with KASCADE lt5
Log Nch
13
Lateral distributions of charged
particles showing the good performance of the
array
0 ltqlt18
14
Egt1017 eV ?4300 events
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
15
Way to all particle Energy Spectrum1) Constant
Intensity Cut Method (Nch or Nm)
Integral Flux I(gtNch)
Log Nch

• Integral spectra measured in
• different bins of zenith angle
• 2) For a given I(gtNX) ? NX(q)

3) Get Attenuation Curves
16
4) Nch,m(q) ? Nch,m(qref)
5) Nch,m(qref) is converted to primary
energy Influence of interaction models, MC
statistics, slope used in the simulation
Energy Spectrum measurements starting from
different observables. Cross checks Systematics
A first study of the systematic (Nm)
uncertainties has been performed For E ?1017 eV
? DE ?22
17
Way to all particle Energy Spectrum2) 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 Spectrum3) Primary
energy estimated event by event

• Nch (or N?) as primary energy estimator
• Log(Nch/N?) as mass and shower fluctuation
  estimator

log10(E)a(k)?log10(Nch)b(k) kf(Nch/N?,Nch)
H
Fe
Number of Events
from the ratio of reconstructed/true
flux systematic difference (different
primaries) lt5 for Egt1016 eV
original reconstructed
Log E(GeV)
Log E(GeV)
From the bin to bin fluctuations Uncertainty 15
for Egt1016 eV
19
First Results from KASCADE-Grande (ICRC 2007)
Anisotropy

• 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.

20
Conclusions

• KASCADE-Grande is measuring in the 10-1000 PeV
  energy range since January 2004
• Experiment performances
• angular resolution lt0.7
• core resolution ? 5m
• Shower size resolution 20
• Energy Spectrum and Primary composition studies
  are on the way

21
(No Transcript)