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

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

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

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 GP Imponente - EEE Project

Typical telescope (Bologna) 80 cm 82 cm 160 cm  MRPC 3 MRPC 2 MRPC 1 GP Imponente - EEE Project

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

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

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 GP Imponente - EEE Project

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) GP Imponente - EEE Project

Counts/strip Uniform distribution GP Imponente - EEE Project

GP Imponente - EEE Project Tracks view GP Imponente - EEE Project

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

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) GP Imponente - EEE Project

GP Imponente - EEE Project X-Y resolution Longitudinal resolution: 1.5 cm Transverse resolution: < 1cm Angle reconstructed Space resolution is uniform for all angles GP Imponente - EEE Project resolution

Reconstructed muon angular distribution and MC simulation (@80 cm) p m GP Imponente - EEE Project

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