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Draft cosmic paper  Here
LHCb paper (and the other papers) Published 14 August 2008
Muon Posters: Pit   -  HCP 2005

B. Schmidt - IEEE Nuclear Science Symposium, Dresden, talk (22 October '08)
A. Satta - Physics at LHC, Split, Croatia, talk (3 October '08)
G. Lanfranchi - 5th International Workshop on the CKM Unitary Triangle, Rome, talk (9-12 September '08)
S. Vecchi - 2nd WS on Theory, Phenomenology and Experiments in heavy flavour physics, Capri, talk (16-18 June '08)
A. Sarti - 19th Hadron Collider Physics Symposium 2008 (HCP 2008), talk (27-31 May '08)
S. Brusa - Villa Olmo Conference, Como, talk (8-12 October '07)
W. Bonivento - HCP Symposium, La Biodola, talk (20-26 May '07)
E. Santovetti - DIS 2007 Conference, Munich, talk (16-20 April '07)
G. Lanfranchi - Lake Louise 2007 Conference, Alberta, talk (19-24 February '07)
A. Massafferri - IEEE 2006 Conference, San Diego, talk (29 October - 4 November '06)
D. Pinci - 10th Topical Seminar on Innovative Particle and Radiation Detectors (Siena 2006), talk (1-5 October '06)
R. Antunes Nobrega -12th Workshop on Electronics for LHC and future Experiments (LECC 2006), talk (25-29 September '06)
S. De Capua - 11th Int. Conf. on B-Physics at Hadron Machines (Beauty 2006), talk (25-29 September '06)
G. Passaleva - II HERA-LHC Workshop, talk (6-9 June '06)
A. Sarti - La Biodola 2006, talk (21-27 May '06)
K. Mair - IEEE2005 Conference, talk (23-29 October '05)
M. Lenzi - Villa Olmo Conference, Como, talk (17-21 October '05)
K. Mair - 55th Jahrestagung der OEPG, poster (27-29 September '05)
R. Nobrega - LECC 2005 Workshop, poster (12-17 September '05)
W. Rinaldi - LECC 2005 Workshop, poster (12-17 September '05)
E. Policarpo - LECC 2005 Workshop, poster (12-17 September '05)
W. Bonivento - LECC 2005 Workshop, talk (12-17 September '05)
A. Satta - INFN Milano Conference, talk (12-17 September '05)
A. Sarti - HCP05 Workshop, poster (4-9 July '05)
C. Deplano - IEEE 2004, talk (17-19 October '04)
W. Bonivento - IEEE 2004, talk (17-19 October '04)
P. de Simone - IEEE 2004, talk (17-19 October '04)
J-S. Graulich - IEEE 2004, talk (17-19 October '04)
S. De Capua - VII RPC Workshop, talk (20-22 October '03)
B. Schmidt - IEEE 2003, talk (19-25 October '03)
G. Felici - Amsterdam 2003, talk (19-25 October '03)
D. Domenici - La Biodola 2003, talk (25-31 May '03)
A. Satta - LHC 2003 Fermilab, talk (1-3 May '03)
A. Cardini - IEEE 2002, talk (10-16 November '02)
F. Murtas - IEEE 2002, talk (10-16 November '02)
G. Passaleva - Siena 2002, talk (21-24 October '02)
G. Carboni - FPCP 2002 Philadelphia, talk (1-3 May '02)
M. Poli Lener - Instro 02 Novosibirsk, talk (28 February '02)

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Muon Overview
Artist's view of LHCb. The muon detectors of stations M2-M5 are in red, the iron filters in green. The detectors can slide sidewise the beam line to allow access. The figure shows the right-hand side detectors in retracted (maintenance) position. Station M1 is located in front of the calorimeters (blue and light blue). The support infrastructure is not shown.

System Overview

The purpose of the LHCb Muon System is to provide fast (L0) triggering and offline muon identification.

The system is made of five Stations (M1-M5) of rectangular shape, covering an acceptance of ±300 mrad (horizontally) and ±200 mrad (vertically). M1 is placed in front of the SPD/PS. M2-M5 follow the Hadron Calorimeter (HCAL) and are separated by iron filters. The stations cover an area of 435 m2. The total absorber (including the calorimeters) is approximately 20 Interaction Lengths.

The acceptance of the Muon System is about 20 % for muons from inclusive b decays.

Each station is divided into four regions, R1 to R4, with increasing distance from the beam axis. All the regions have approximately the same acceptance, and their granularity is shaped according to the particle density in that region in order to keep occupancy roughly constant over the detector. The granularity of the readout is higher in the horizontal plane, in order to give an accurate measurement of the track momentum and Pt.

The information must be gathered within 20 ns, so the detectors are optimized for speed. Therefore the choice went to Multi Wire Proportional Chambers (MWPC) with 2 mm wire spacing and a small gas gap (5 mm). Triple-GEM detectors are used in the innermost region (R1) of Station M1. This choice was dictated by the better aging properties of this type of detector. There are 1380 chambers in the Muon System, of 20 different sizes.

The detectors provide space point measurements of the tracks, giving a binary (yes/no) information. In order to provide this information, different readout method are employed in the various parts of the detector:
  • Anode wire readout
  • Cathode pad readout
  • Mixed (anode/cathode pad) readout
A total of 126000 front-end readout channels are used. The electronics is based on custom rad-hard chips specially developed for the Muon System.

The Muon Trigger is based on a five-fold coincidence of the stations. Therefore its efficiency goes like e^5, where e is the efficiency of one station. In order to assure the necessary high efficiency and adequate redundancy, four layers of detectors are used in M2-M5. Two layers are used in M1 (this is a compromise between performances and material budget before the ECAL/PS/SPD). In practice, since we work at fixed Minimum Bias rate, the dependence on e is less steep (approximately like e^3.5). In normal operating conditions e = 46 % for b -> m X events inside the acceptance.