Folie 1

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Calibration of the hadron calorimeter of the
KASCADE-Grande experiment with a high-energy
particle beam
Stefan Plewnia Forschungszentrum Karlsruhe for
the KASCADE-Grande Collaboration
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- Hadronic component of EAS consists of mesons,
neutrons, protons, and fragments of nuclei -
Observables for ground-based measurements are
- energy of the detected hadron - track of
the hadron - number of hadrons in an EAS gt
hadronic observables are correlated to the
primary nucleus
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The KASCADE-Experiment

• KASCADE Calorimeter
• - 320 m2 detection area
• - 11 ?i depth
• - 9 layers of ionization chambers
• - 11000 chambers with 44000
• electronic channels
• - Energy threshold EHgt20 GeV
• - Spatial resolution of 25x25 cm2

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The ionization chambers
- Filled with TMP (Tetramethylpentane) or TMS
(Tetramethylsilane) as active medium - Stable
signal yield over a long period of time -
Operation at room temperature - Better
precision in energy measurement than detectors
with gas
TMP
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CERN Test Setup

• Test at the SPS-H4 beamline (June and July 2003)
• - Protons, pions, electrons, and muons from 15 to
  350 GeV

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The Calorimeter
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Calibration

• - Electronic calibration with defined pulses
• conversion of ADC counts into fC
• - Measurement of muons with 50 GeV
• Energy loss in chambers can be calculated
  (Bethe-Bloch formula)
• or derived from MC-Simulations
• - The measured charge depends on - dE/dx
• -
  primary recombination
  - losses due to impurities

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Calibration
Collected charge
Charge yield of electrons escaping primary
recombination
From simulation/calculation (Bethe-Bloch)
Charge collection function
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50 GeV muons at three high voltages

• Charge collection function is fitted to data
• - One parameter lifetime t

t is used as calibration constant for all other
measurements
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Muons at different high voltages
After calibration All layers show reasonable
energy deposits for muons
-gt Calibration constants can be used for further
analysis
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Longitudinal distributions for pions/protons
Maximum of energy deposit ln(E)
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Longitudinal distributions for electrons
Calorimeter is optimized for hadrons -gt sampling
is inadequate for electrons
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Comparison of data with MC simulation

• Monte Carlo Simulation
• Based on GEANT 3.21
• Signal damping for strongly ionizing particles
  implemented according to prev. measurements
• Chamber geometry is taken into account
• Simulations with hadrons, electrons, and muons
  at various energies
• - Statistics is about 10 of data

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Simulation and data for pions
?Simulation and measurement agree !
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Energy sum for hadrons and electrons
SE sum of energy deposit in all layers

• Measured energy E0

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Energy resolution for hadrons
sE/E 27 at 150 GeV
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Summary

• Calorimeter worked fine, preliminary results are
  encouraging
• Data and simulation agree satisfyingly

Outlook

• Further analysis is in progress
• Difference between MC and data will be
  investigated
• Results will improve the knowledge about the
  chambers and the reconstruction of KASCADE data