Streamlined calibrations of the ATLAS precision muon chambers for initial LHC running

Amram, N.; Ball, R. C.; Benhammou, Y.; Moshe, M. Ben; Dai, T.; Diehl, E. B.; Dubbert, J.; Etzion, E.; Ferretti, C.; Gregory, J.; Haider, S.; Hindes, J.; Levin, D.; Manilow, E.; Thun, R. P.; Wilson, A.; Weaverdyck, Curtis; Wu, Y.; Yang, Hai; Zhou, B.; Zimmermann, S.

doi:10.1016/j.nima.2011.12.086

Cited by 3 publications

(5 citation statements)

References 12 publications

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“…Figure 12 shows the predicted change in the drift time as a function of drift radius for variations of temperature, pressure and high voltage from their reference values. This drift time response was previously validated with temperature data [12]. The maximum effect on the drift time is at the tube wall as expressed in equation (5.1), where the temperature correction is −2.6 ns/K, while the pressure correction function scales as −0.1 K/mbar relative to the temperature correction.…”

Section: δP Correctionmentioning

confidence: 68%

“…The principal GMC output is a measurement of the maximum drift time, t max = t w −t 0 , where t w is the arrival time of a hit located at the tube wall. A drift time spectrum, similar to figure 2, is computed for standard operating conditions by applying a correction function [12] based on the output of chamber-mounted pressure and temperature sensors. The tail end of the spectrum is fitted using a modified Fermi-Dirac sigmoid function similar to that used to obtain the t 0 offsets, and the t max is defined as a fit parameter, as described in ref.…”

Section: Gas Monitor Chambermentioning

confidence: 99%

“…After local GMC temperature and pressure corrections are applied, the URT registers only changes in the gas composition. Based on the daily average of measurements from detector-mounted thermal sensors, the URT is converted into chamber-specific R(t) functions [12]. These chamber R(t) functions are further tuned by the δP correction parameter, as detailed in section 5.2.…”

Section: Gas Monitor Chambermentioning

confidence: 99%

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Resolution of the ATLAS muon spectrometer monitored drift tubes in LHC Run 2

Collaboration¹

2019

J. Inst.

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The momentum measurement capability of the ATLAS muon spectrometer relies fundamentally on the intrinsic single-hit spatial resolution of the monitored drift tube precision tracking chambers. Optimal resolution is achieved with a dedicated calibration program that addresses the specific operating conditions of the 354 000 high-pressure drift tubes in the spectrometer. The calibrations consist of a set of timing offsets and drift time to drift distance transfer relations, and result in chamber resolution functions. This paper describes novel algorithms to obtain precision calibrations from data collected by ATLAS in LHC Run 2 and from a gas monitoring chamber, deployed in a dedicated gas facility. The algorithm output consists of a pair of correction constants per chamber which are applied to baseline calibrations, and determined to be valid for the entire ATLAS Run 2. The final single-hit spatial resolution, averaged over 1172 monitored drift tube chambers, is 81.7 ± 2.2 µm. K: Gaseous detectors; Muon spectrometers; Particle tracking detectors (Gaseous detectors); Wire chambers (MWPC, Thin-gap chambers, drift chambers, drift tubes, proportional chambers etc)

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Section: δP Correctionmentioning

confidence: 68%

Section: Gas Monitor Chambermentioning

confidence: 99%

Section: Gas Monitor Chambermentioning

confidence: 99%

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Resolution of the ATLAS muon spectrometer monitored drift tubes in LHC Run 2

Collaboration¹

2019

J. Inst.

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“…A further application of this system [3] is to produce a standard RT function specific to well measured gas temperature, gas pressure and to the actual MDT gas used in the underground ATLAS MDT chambers.…”

Section: Gmc Results For Lhc Run1mentioning

confidence: 99%

Online precision gas evaluation of the ATLAS Muon Spectrometer during LHC Run1

Geng

2014

2014 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)

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Abstract-The ATLAS Muon Spectrometer, a six story structure embedded in a toroidal magnetic field, is constructed of nearly 1200 Monitored Drift Tube chambers (MDTs) containing 354,000 aluminum drift tubes. The operating gas is 93% Ar + 7% CO2 with a small amount of water vapor at a pressure of 3 bar. The momentum resolution required for ATLAS physics demands that MDT gas quality and the associated gas dependent calibrations be determined with a rapid feedback cycle. During the LHC Run1, more than 2 billion liters of gas flowed through the detector at a rate 100,000 l/hr. Online evaluation of MDT gas in real time and the associated contribution to the determination of the time-to-space functions was conducted by the dedicated Gas Monitor Chamber (GMC). We report on the operation and results of the GMC over the first three years of LHC running. During this period, the GMC has operated with a nearly 100% duty cycle, providing hourly measurements of the MDT drift times with 1 ns precision, corresponding to minute changes in gas composition.

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“…The temperature gradient in the ATLAS cavern is about 10 • C, as illustrated in figure 8 of ref. [45]. This gradient is due to the air circulation in the cavern, with lower temperatures at the bottom of the detector.…”

Section: Rpc Current Measurementsmentioning

confidence: 99%

Performance of the ATLAS RPC detector and Level-1 muon barrel trigger at √(s)=13 TeV

Aad

Abbott

et al. 2021

J. Inst.

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Large Hadron Collider (LHC) employs a trigger system consisting of a first-level hardware trigger (L1) and a software-based high-level trigger. The L1 muon trigger system selects muon candidates, assigns them to the correct LHC bunch crossing and classifies them into one of six transverse-momentum threshold classes. The L1 muon trigger system uses resistive-plate chambers (RPCs) to generate the muon-induced trigger signals in the central (barrel) region of the ATLAS detector. The ATLAS RPCs are arranged in six concentric layers and operate in a toroidal magnetic field with a bending power of 1.5 to 5.5 Tm. The RPC detector consists of about 3700 gas volumes with a total surface area of more than 4000 m 2 . This paper reports on the performance of the RPC detector and L1 muon barrel trigger using 60.8 fb −1 of proton-proton collision data recorded by the ATLAS experiment in 2018 at a centre-of-mass energy of 13 TeV. Detector and trigger performance are studied using boson decays into a muon pair. Measurements of the RPC detector response, efficiency, and time resolution are reported. Measurements of the L1 muon barrel trigger efficiencies and rates are presented, along with measurements of the properties of the selected sample of muon candidates. Measurements of the RPC currents, counting rates and mean avalanche charge are performed using zero-bias collisions. Finally, RPC detector response and efficiency are studied at different high voltage and front-end discriminator threshold settings in order to extrapolate detector response to the higher luminosity expected for the High Luminosity LHC.

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Streamlined calibrations of the ATLAS precision muon chambers for initial LHC running

Cited by 3 publications

References 12 publications

Resolution of the ATLAS muon spectrometer monitored drift tubes in LHC Run 2

Resolution of the ATLAS muon spectrometer monitored drift tubes in LHC Run 2

Online precision gas evaluation of the ATLAS Muon Spectrometer during LHC Run1

Performance of the ATLAS RPC detector and Level-1 muon barrel trigger at √(s)=13 TeV

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