1. Multigap Resistive Plate Chambers for EAS study in the EEE Project
Project Leader: Antonino Zichichi
GP Imponente - EEE Project
Presented by G. Imponente
ICRC, July 2007

2. GP Imponente - EEE Project
Summary
Outlook of the EEE Project
The MRPC telescope
Efficiency and functionality
Space and time resolution
Track reconstruction
Conclusions
GP Imponente - EEE Project

3. GP Imponente - EEE Project
The EEE Project
Started in 2005, was conceived and is led by A. Zichichi:
Looking for faraway sites coincidences and Unexpected Events
bringing Science in the youths' hearts through EAS study
using a frontier detector built and operated by themselves
Tracking the HE muon component of EAS with Multigap Resistive Plate Chambers (MRPC) telescopes
Muon tracking and timing accurate measurements strongly reduce accidental concidences.
GP Imponente - EEE Project

4. GP Imponente - EEE Project
Supporting Institutions
Centro Fermi, INFN, CERN, MUR, CNR, INGV, Centro Majorana EMFCSC
Pilot cities
Bologna
Cagliari
Catania
Grottaferrata (Roma)
L’Aquila
Lecce
Torino
Telescopes are going to be also in Bari, Salerno and Firenze.
Network will be heavily updated soon:
>=3 telescopes each site
many more sites already involved
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5. Typical telescope (Bologna)
80 cm
82 cm
160 cm 
MRPC 3
MRPC 2
MRPC 1
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6. MRPC basics
The MRPC is a stack of resistive plates, transparent to the avalanches generated inside the gas gaps 300 mm. The induced signal on external electrodes is the sum over all the gaps
Gas: mixture of Freon (C2H2F4) + SF6 (95% + 5%) flow: 2.4 l/h
Full efficiency – streamer regime
High time resolution
t <= 100 ps
Carbon layer
Mylar
glass
Pick-up electrode
Anode +10 KV
Cathode -10 kV
HV is applied to external glass electrodes
Internal glass sheets are floating
Developed by the ALICE TOF group, to achieve excellent time resolution (of order 50 ps) and efficiency

7. GP Imponente - EEE Project
Gas gaps
Fishing line creates uniform small gaps (300 mm) between glass electrodes
GP Imponente - EEE Project

8. GP Imponente - EEE Project
Front-End electronics
The detector can provide 2-dimensional position information through individual (24) 2.5 cm strips with 7 mm spacing in the transverse direction (y) and right-left time comparison in the longitudinal one (x).
Pitch: 3.2 cm
Width: 2.5 y x
An ultra-fast and low power front-end amplifier/
discriminator ASIC specifically designed for the MRPC is being used (NINO ASIC).
FE cards (24 channels)
Tot. # of readout channels = 144
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9. GP Imponente - EEE Project
MRPC Efficiency
High efficiency even without gas flow
(> 1 month)
Total currents (A)
Anti-correlation of muon counts with atmospheric pressure (Catania set up)
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10. Counts/strip Uniform distribution
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11. GP Imponente - EEE Project
Tracks view
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12. MRPC Self-calibration
Cumulative distribution
Total width Lchamber
Sigma function x gaussian
Centering the single distributions  strip alignments
Distributions width  measurement of signal speed
Signal Speed along the copper strips is measured directly from data v = (6.1 § 0.1 ns/m)-1
Strip per strip analysis, all chambers, all strips
GP Imponente - EEE Project

13. GP Imponente - EEE Project
Space resolution
Being y the coordinate along the strips, we check how much the “expected” value of it for the chamber in the middle differs from the measured one.
Tracks with at most 2 strips on/chamber
 y2 (cm)
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14. GP Imponente - EEE Project
X-Y resolution
Longitudinal resolution: cm
Transverse resolution: < 1cm
Angle reconstructed
Space resolution is uniform for all angles
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resolution

15. Reconstructed muon angular distribution and MC simulation (@80 cm)p m
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16. GP Imponente - EEE Project
Conclusions…
MRPC are an efficient and powerful tool.
Several MRPC telescopes are installed in High Schools, ready to collect coincidence data.
Accurate space resolution (up to 1 cm) and time resolution ( apprx 100 ps)
… and ongoing work…
Turn on more stations (» 100)
Looking for coincidences between nearby and faraway telescopes
GP Imponente - EEE Project