RPC muon trigger
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3 concentric cylindrical layers of RPC at 5, 7.5 and 10m radius
2 gas gaps and 2+2 readout planes for each detector element
2 mm gas gap with bakelite electrodes
Gas mixture: tetrafluorethane (C2H2F4) 94.7%
isobutane (C4H10) 5%
sulfur exafluoride (SF6) 0.3%
RPCs working in saturated avalanche mode
Efficiency: ~98%
Time resolution: ~ 1 ns
Spatial resolution: 5-10 mm
Rate capability: ~ 1000 Hz/cm2
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Surface 3650 m2
Readout channels: 360k
Detector
MDT
CSC
RPC
TGC
Region
B/E
Nominal
Pseudorapidity range
HV
η<2.7
(340k ch.)
EI
2.0<η<2.7
(31k ch.)
B
η<1.05
(360k ch.)
E
1.05<η<2.4
(320k ch.)
3,080V
Gas mixture
and gain
Ar : CO2
(93/7) : 3bar
2E4
1,800V
Ar : CO2
(80/20)
6E4
9,600V
C2H2F4 iso-C4H10 SF6
( 94.7 : 5.0 : 0.3 )
1E7
2,800V
CO2 : n-Pentane
( 55 : 45 ) 17deg.
3E5
Spatial
resolution
better than
100μm
~cm
but fast
for LVL1
2
Detector description
ϕ strip panel
2mm gas gap
η strip panel
η strip panel
2mm gas gap
ϕ strip panel
Each chamber contains a double-layer of RPCs, layer 0 (closest to IP) and layer 1
Each layer made of 2mm thick gas volumes is equipped with 2 panels of readout strips
25-35mm wide in orthogonal coordinates (η,ϕ)
Strip signals are read out by the front-end electronics connected at the strip edge and
encapsulated in the chamber box
RPC signals are used to provide triggers and the azimuthal coordinate of the muon tracks
LVL1 trigger
Two trigger logics are implemented:
Low-pT trigger
RPC2 && RPC1
Hits in 3 of the 4 inner layers
Hit in station RPC2 (BM pivot) extrapolated
to station RPC1 (BM confirm) along a
straight line through interaction point
Look for hit in station RPC1 within a
coincidence window
High-pT trigger
Low-pT && RPC2 && RPC3
Logical AND of Low PT and at least 1 of
the 2 planes in station RPC3 (BO confirm)
within a coincidence window
Coincidences are performed in coincidence matrices (CM) hosted inside PAD boxes placed on detector
W candidate with muon trigger
Ruolo di Bologna
• Entrati nel 2005 (senza sapere bene cosa ci aspettasse ...)
• Spinta a contribuire su questo sistema con vari problemi – altri gruppi:
RM2 (progetto), NA, LE
• Sistema fondamentale di ATLAS
• Contributo alla riorganizzazione delle fasi di pretest, lavori di
riparazioni off e on-detector, cablaggi, commissioning del sistema
• II fase:
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Espansione verso il DCS (fatto ex-novo o quasi)
Monitor Online della qualita` dei dati
System experts
Simulazione del LVL1
– Debug & commissioning del LVL1 (strade di trigger ecc.)
Attivita` in corso
• Rifacimento sistema distribuzione HV
• Semplificazione e sostituzione connettori
• Lavori di assemblaggio e costruzione fatti
presso una ditta esterna
• In sezione test HV (moduli NIM di Alice)
Persone
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Lorenzo Bellagamba
– simulazione LVL1, database, analisi
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Marcello Bindi
– DCS / database (expert on call)
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Davide Boscherini
– Responsabile attivita` RPC
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Alessia Bruni
– Monitor Online
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Graziano Bruni
– simulazione LVL1 (debug & trigger roads), analisi
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Massimo Corradi
– simulazione LVL1 (trigger roads & overlaps)
– coordinatore sottogruppo “Low PT muons for resonances”
• supporto J/Y, b
– effic. J/Y T&P
– spettro 2 m dalla r alla Z – metodi per separare prompt da fake
– Rate muoni fake (K0  p, D0  Kp)
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Alessandro Polini
– DCS / DAQ, (expert on call) – IBL
AIDA
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GIF++ infrastructure
4 anni dal gennaio 2011
BA, BO, LNF, RM2, Weizman, INRE, NTUA
1a milestone: dopo 18 mesi [activity report
riguardo il design della infrastruttura]
BO: sviluppo DCS (Polini, Bindi) + contributi al
cosmic ray test stand (Boscherini)
Impegno “minimo” di persone comunque al
CERN
Vantaggi: utenti “privilegiati” della facility
Project leader: Davide Boscherini