Performance of the CMS drift tube chambers with cosmic rays

Abstract

Studies of the performance of the CMS drift tube barrel muon system are described, with results based on data collected during the CMS Cosmic Run at Four Tesla. For most of these data, the solenoidal magnet was operated with a central field of 3.8 T. The analysis of data from 246 out of a total of 250 chambers indicates a very good muon reconstruction capability, with a coordinate resolution for a single hit of about 260 µm, and a nearly 100% efficiency for the drift tube cells. The resolution of the track direction measured in the bending plane is about 1.8 mrad, and the efficiency to reconstruct a segment in a single chamber is higher than 99%. The CMS simulation of cosmic rays reproduces well the performance of the barrel muon detector.

The performance of the CMS muon detector in proton-proton collisions at √s= 7 TeV at the LHC

“…Previous publications [4][5][6][7][8][9][10][11][12][13][14] have described the performance of the muon system during the long cosmic-ray-muon runs of 2008 and 2009. Here we describe the performance of the CMS muon detectors using a data sample accumulated at √ s = 7 TeV during the 2010 LHC proton-proton physics run corresponding to an integrated luminosity of approximately 40 pb −1 .…”

Trigger-less readout and unbiased data quality monitoring of the CMS drift tubes muon detector

“…The first implementation of the 40MHz data scouting has been deployed in CMS in 2022. The Drift Tube (DT) detector sub-system [8] was chosen for the first deployment, as four chambers (MB1 to MB4 of the DT sector 12 of wheel +2) have been instrumented with Phase-2 On-Board DT readout boards (OBDT) [9], performing the Time-to-Digital Conversions of the DT hits time in FPGA with nanosecond resolution. In total, the DT Phase-2 Upgrade demonstrator is equipped with 13 OBDT boards, and 3120 individual channels.…”

Design and Description of the CMS Magnetic System Model

“…In the Compact Muon Solenoid (CMS) detector [11] at the LHC [8], the magnetic field is provided by a wide-aperture superconducting thin solenoid [33] with a diameter of 6 m and a length of 12.5 m, where a central magnetic flux density |B 0 | of 3.8 T is created by an operational direct current of 18.164 kA [34][35][36]. The CMS multi-purpose detector, schematically shown in Figure 1, includes a silicon pixel tracking detector [37], a silicon strip tracking detector [38], a solid crystal electromagnetic calorimeter [39] to register e and γ particles, and a hadron calorimeter of total absorption [40] both located inside the superconducting solenoid, as well as a muon spectrometer [41][42][43][44] and a forward hadron calorimeter [45], both located outside of the superconducting coil. One of the main goals of the CMS setup was to detect the Higgs boson by its decay mode into four leptons H→4l, where l = e, µ, and the technical design of all the detector systems has led to the success in achieving this purpose.…”

“…Finally, a muon spectrometer covering the pseudorapidity interval |η| < 2.4, consists of three systems for measuring muon momenta-drift tube chambers [41] in the central part of the muon spectrometer, cathode-strip chambers [42] in the endcap parts, and resistive plate chambers [43]. The global fit of the muon trajectory in the muon spectrometer to the parameters of the muon trajectory found and reconstructed in the tracking detectors provides a resolution in the particle transverse momentum, averaged over the azimuthal angle and pseudorapidity, at a level from 1.8% for the muon transverse momentum of p T = 30 GeV/c to 2.3% for p T = 50 GeV/c [44].…”