M. Anelli, R. AntunesNobrega, G. Auriemma, W. Baldini, G. Bencivenni, R. Berutti, V. Bocci, N. Bondar, W. Bonivento, B. Botchin, S. Cadeddu, P. Campana, G. Carbonih, A. Cardini, M. Carletti, P. Ciambrone, E. Dane, S. DeCapua, C. Deplano, P. DeSimone, F. Dettori, A. Falabella, F. Ferreira Rodriguez, M. Frosini, S. Furcas, G. Graziani, L. Gruber, A. Kashchuk, A. Lai, G. Lanfranchi, M. Lenzi, O. Levitskaya, K. Mair, O. Maev, G. Manca, G. Martellotti, A. Massafferri Rodrigues, R. Messi, F. Murtas, P. Neustroev, R. G. C. Oldemane, M. Palutan, G. Passaleva, G. Penso, A. Petrella, D. Pinci, S. Pozzi, G. Sabatino, B. Saitta, R. Santacesaria, E. Santovetti, A. Saputi, A. Sarti, C. Satriano, A. Satta, M. Savrie, B. Schmidt, T. Schneider, A. Sciubba, P. Shatalov, S. Vecchi, M. Veltri, S. Volkov, A. Vorobyev
The LHCb Muon system performance is presented using cosmic ray events collected in 2009. These events allowed to test and optimize the detector configuration before the LHC start. The space and time alignment and the measurement of chamber efficiency, time resolution and cluster size are described in detail. The results are in agreement with the expected detector performance.
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Muon identification is of paramount importance for the physics programme of LHCb. In the upgrade phase, starting from Run 3 of the LHC, the trigger of the experiment will be solely based on software. The luminosity increase to $2\times10^{33}$ cm$^{-2}$s$^{-1}$ will require an improvement of the muon identification criteria, aiming at performances equal or better than those of Run 2, but in a much more challenging environment. In this paper, two new muon identification algorithms developed in view of the LHCb upgrade are presented, and their performance in terms of signal efficiency versus bac…
A new method has been developed to check the correct behaviour of the frontend electronics of the LHCb muon detector. This method is based on the measurement of the electronic noise rate at different thresholds of the frontend discriminator. The method was used to choose the optimal discriminator thresholds. A procedure based on this method was implemented in the detector control system and allowed the detection of a small percentage of frontend channels which had deteriorated. A Monte Carlo simulation has been performed to check the validity of the method.
The performance of the muon identification in LHCb is extracted from data using muons and hadrons produced in J/ψ->μμ, Λ->pπand D^{\star}->πD0(Kπ) decays. The muon identification procedure is based on the pattern of hits in the muon chambers. A momentum dependent binary requirement is used to reduce the probability of hadrons to be misidentified as muons to the level of 1%, keeping the muon efficiency in the range of 95-98%. As further refinement, a likelihood is built for the muon and non-muon hypotheses. Adding a requirement on this likelihood that provides a total muon efficiency at the lev…
The MUON Detector (MD) of LHCb is one of the largest instruments of this kind worldwide, and one of the most irradiated. It has performed exceptionally well during the RUN1 and RUN2 of the LHC at an instantaneous luminosity of 4$\times$10$^{32}$ cm$^{-2}$s$^{-1}$, with tracking inefficiencies at the level of 1$\%$ and 2.6$\%$, respectively. Looking forward for the future LHCb Upgrade 2 (U2) planned in 2031 and aiming in running the detector at increased luminosity by a factor $\sim$50, and at the same time keeping a very high ($\sim$99$\%$) detection efficiency, an option with reuse significan…
A method is described which allows to deduce the dead-time of the front-end electronics of the LHCb muon detector from a series of measurements performed at different luminosities at a bunch-crossing rate of 20 MHz. The measured values of the dead-time range from 70 ns to 100 ns. These results allow to estimate the performance of the muon detector at the future bunch-crossing rate of 40 MHz and at higher luminosity.
The LHCb experiment(Fig. 1), that is presently taking data at CERN (European Center for Nuclear Research) Large Hadron Collider (LHC), aims at the study of CP violation in the B meson sector. Its key elements is the Muon detector [1], which allows triggering, and muon identification from inclusive b decays. The electronic system (Fig. 2) of the whole detector is very complex and its Muon detector Experiment Control System (ECS) allows monitoring and control of a number of Front-End boards in excess of 7000. The present system in charge of controlling Muon detector Front-End (FE) Electronics co…
The preliminary results of an aging test performed at the CERN Gamma Irradiation Facility on a single--gap RPC prototype developed for the LHCb Muon System are presented. The results are based on an accumulated charge density of 0.42 C/cm^2, corresponding to about 4 years of LHCb running at the highest background rate. We observe a rise in the dark current and noise measured with source off. The current drawn with source on steadily decreased, possibly indicating an increase of resistivity of the chamber plates. The performance of the chamber, studied with a muon beam under several photon flux…
Recent results of an aging test performed at the CERN Gamma Irradiation Facility on a single--gap RPC prototype developed for the LHCb Muon System are presented. The results are based on an accumulated charge of about 0.45 C/cm$^2$, corresponding to about 4 years of LHCb running at the highest background rate. The performance of the chamber has been studied under several photon flux values exploiting a muon beam. A degradation of the rate capability above 1 kHz/cm$^2$ is observed, which can be correlated to a sizeable increase of resistivity of the chamber plates. An increase of the chamber da…
A very compact architecture has been developed for the first level Muon Trigger of the LHCb experiment that processes 40 millions of proton-proton collisions per second. For each collision, it receives 3.2 kBytes of data and it finds straight tracks within a 1.2 microseconds latency. The trigger implementation is massively parallel, pipelined and fully synchronous with the LHC clock. It relies on 248 high density Field Programable Gate arrays and on the massive use of multigigabit serial link transceivers embedded inside FPGAs.
The performance of the LHCb Muon system and its stability across the full 2010 data taking with LHC running at ps = 7 TeV energy is studied. The optimization of the detector setting and the time calibration performed with the first collisions delivered by LHC is described. Particle rates, measured for the wide range of luminosities and beam operation conditions experienced during the run, are compared with the values expected from simulation. The space and time alignment of the detectors, chamber efficiency, time resolution and cluster size are evaluated. The detector performance is found to b…
The muon detector of LHCb, which comprises 1368 multi-wire-proportional-chambers (MWPC) for a total area of 435 m2, is the largest instrument of its kind exposed to such a high-radiation environment. In nine years of operation, from 2010 until 2018, we did not observe appreciable signs of ageing of the detector in terms of reduced performance. However, during such a long period, many chamber gas gaps suffered from HV trips. Most of the trips were due to Malter-like effects, characterised by the appearance of local self-sustained high currents, presumably originating from impurities induced dur…
The calorimeter and muon systems are essential components to provide a trigger for the LHCb experiment. The calorimeter system comprises a scintillating pad detector and pre-shower, followed by electromagnetic and hadronic calorimeters. The calorimeter system allows photons, electrons and hadrons to be identified, and their energy to be measured. The muon system consists of five measuring stations equipped with Multi-Wire Proportional Chambers (MWPCs) and triple-Gas Electron Multiplier (GEM) detectors, separated by iron filters. It allows the muons identification and transverse momentum measur…
The LHCb Experiment is preparing a detector upgrade fully exploit the flavour physics potential of the LHC. The whole detector will be read out at the full collision rate and the online event selection will be performed by a software trigger. This will increase the event yields by a facto 10 for muonic and a factor 20 for hadronic final states. Research towards the upgrade has started with the target to install the detector in 2018.
The ATLAS detector is intended to verify the standard model and to search for new physics at the Large Hadron Collider (LHC, CERN). In addition to this primary goal, it also allows detection of muons of cosmic rays. On the other hand, unusual bursts of the muon intensity, which correlate with powerful solar flares were recorded and investigated earlier at the Baksan Underground Scintillation Telescope (BUST, INR, Russia) in period from 1981 to 2006 (~2.5 solar cycles). The nature of the muon bursts and their probable relation to the solar cosmic rays is still not quite clear. ATLAS has an exce…
The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the…
ALICE, a general purpose experiment designed to investigate nucleus-nucleus collisions at the CERN Large Hadron Collider (LHC), has also been used to detect atmospheric muons produced by cosmic-ray interactions in the atmosphere. In this contribution the analysis of the multiplicity distribution of the atmospheric muons detected by ALICE between 2010 and 2013 is presented, along with a comparison with Monte Carlo simulations. Special emphasis is given to the study of high-multiplicity events, i.e. those containing more than 100 reconstructed muons. Such high-multiplicity events demand primary …
The X-ARAPUCA device is the baseline choice for the photon detection system of the first far detector module of the DUNE experiment. We present the results of the first complete characterization of a small scale X-ARAPUCA prototype, which is a slice of a full DUNE module. Its total detection efficiency in liquid argon was measured with three different ionizing radiations: $α$ particles, $γ$'s and muons and resulted to be $\sim$2.2% when the active silicon photomultipliers were biased at +5.0 V of over voltage, corresponding to a Photon Detection Efficiency around 50% at room temperature. This …
The CMS experiment uses self-triggering arrays of drift tubes in the barrel muon trigger to perform the identification of the correct bunch crossing. The identification is unique only if the trigger chain is correctly synchronized. In this paper, the synchronization performed during an extended cosmic ray run is described and the results are reported. The random arrival time of cosmic ray muons allowed several synchronization aspects to be studied and a simple method for the fine synchronization of the Drift Tube Local Trigger at LHC to be developed.
A CdTe double-sided strip detector (CdTe-DSD) is an ideal device for imaging and spectroscopic measure- ments in the hard X-ray range above 10 keV. Recent development enables us to realize an imager with a detection area of ~10 cm${^2}$. An energy resolution of 1-2 keV (FWHM) and a position resolution of a few hundred μm are available from the detector. This type of imager has been long awaited for non-destructive elemental analysis, especially by using negative muons, because energies of characteristic X-rays from muonic atoms are about 200 time higher than those from normal atoms. With the m…
The muon spectrometer of the ATLAS experiment is one of the largest detectors ever built. At the LHC, new physics signs could appear through high momentun muons (1 TeV). Identification and precise momentum measurement of such muons are two of the main challenges of the ATLAS muon spectrometer. In order to get a good resolution for high energy muons (i.e. 10% at 1 TeV), the accuracy on the alignment of precision chambers must be of the order of 50 microns. Several procedures have been developed to reach such a precision. This document describes complementary techniques used to align the muon su…
The MicroBooNE experiment is a liquid argon TPC experiment designed for short-baseline neutrino physics, currently running at Fermilab. Due to its location near the surface, cosmic muons can be a source of backgrounds to many analyses and having a good understanding of the cosmic rays will be very valuable for the experiment. These proceedings describe the physics motivation, setup, and performance of a small external muon counter system, which will provide improved calibration for the liquid argon TPC and better understanding of the cosmogenic background.
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 microns, 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 re…
The performance of the Local Trigger based on the drift-tube system of the CMS experiment has been studied using muons from cosmic ray events collected during the commissioning of the detector in 2008. The properties of the system are extensively tested and compared with the simulation. The effect of the random arrival time of the cosmic rays on the trigger performance is reported, and the results are compared with the design expectations for proton-proton collisions and with previous measurements obtained with muon beams.
We report the timing and spatial resolution from the Muon Telescope Detector (MTD) installed in the STAR experiment at RHIC. Cosmic ray muons traversing the STAR detector have an average transverse momentum of 6 GeV/c. Due to their very small multiple scattering, these cosmic muons provide an ideal tool to calibrate the detectors and measure their timing and spatial resolution. The values obtained were ~100 ps and ~1-2 cm, respectively. These values are comparable to those obtained from cosmic-ray bench tests and test beams.
The effects induced by muons with very low energies are usually neglected. In fact, they could represent a source of radioactive background due to capture processes in different materials, which in most of cases produce radioactive isotopes, and thus they must be taken into account. Plastic track detectors have been used in the present paper to measure the ratio between the vertical and horizontal components of the flux of very low energy terrestrial muons at ground level. The data have been collected during 160 days.
Camera image sensors can be used to detect ionizing radiation in addition to optical photons. In particular, cosmic-ray muons are detected as long, straight tracks passing through multiple pixels. The distribution of track lengths can be related to the thickness of the active (depleted) region of the camera image sensor through the known angular distribution of muons at sea level. We use a sample of cosmic-ray muon tracks recorded by the Distributed Electronic Cosmic-ray Observatory to measure the thickness of the depletion region of the camera image sensor in a commercial smart phone, the HTC…
We report on the construction and upgrade of a Lawrence Berkeley National Laboratory Cosmic Muons Detector. We modify the electronics and mechanics to achieve a highly efficient gamma-ray and cosmic-ray detector. Each detector module uses a one-inch-thick scintillator, attached to a photomultiplier tube (PMT) and mounted on a solid aluminum frame. The detector uses scintillation to transform passing radiation into detectable photons that are guided toward a photocathode surface of the PMT, triggering the release of photoelectrons that are then amplified to yield measurable electronic signals. …
We describe a hands-on accurate demonstrator for cosmic rays realized by six high school students, whose main aim is to show the relevance and the functioning of the principal parts of a cosmic rays telescope (muon detector), with the help of two large size wooden artifacts. The first one points out how cosmic rays can be tracked in a muon telescope, while the other one shows the key avalanche process of electronic ionization that effectively allows muon detection through a photomultiplier. Incoming cosmic rays are visualized in terms of laser beams, whose 3D trajectory is highlighted by the t…
In the current paper, we analyzed the variation of cosmic radiation flux with elevation, time of the year and ambient temperature with the help of a portable cosmic muon detector, the construction of which was completed by a team from Southern Arkansas University (SAU) at Lawrence Berkeley National Laboratory (LBNL). Cosmic muons and gamma rays traverse two synchronized scintillators connected to two photomultiplier tubes (PMT) via light guides, and generate electronic pulses which we counted using a Data Acquisition Board (DAQ). Because muons are the product of collisions between high-energy …
A muon telescope based on 8 water cherenkov detectors was mounted at Basic Environmental Observatory - Moussala - Institute for Nuclear Research and Nuclear Energy - Bulgarian Academy of Science. The telescope will be used for continuous measuring the intensity of the muon component of cosmic rays, exploring its variations and possible correlations with environment parameters. A detailed description of the device is presented in this paper.
This paper describes the calibration procedure for the drift tubes of the CMS barrel muon system and reports the main results obtained with data collected during a high statistics cosmic ray data-taking period. The main goal of the calibration is to determine, for each drift cell, the minimum time delay for signals relative to the trigger, accounting for the drift velocity within the cell. The accuracy of the calibration procedure is influenced by the random arrival time of the cosmic muons relative to the LHC clock cycle. A more refined analysis of the drift velocity was performed during the …
This paper reports a series of measurements that characterize the directional dependence of the scintillation response of crystalline anthracene to incident DT neutrons, DD neutrons, Cs-137 gamma rays, and, for the first time, cosmic ray muons. The neutron measurements give the amplitude and pulse shape dependence on the proton recoil direction over one hemisphere of the crystal, confirming and extending previous results in the literature. In similar measurements using incident gamma rays, no directional effect is evident, and any anisotropy with respect to the electron recoil direction is con…
In Low Background Laboratory at Institute of Physics Belgrade, plastic scintillators are used to continuously monitor flux of the muon component of secondary cosmic rays. Measurements are performed on the surface as well as underground (25 m.w.e depth). Temperature effect on muon component of secondary cosmic rays is well known and several methods to correct for it are already developed and widely used. Here, we apply integral method to calculate correction coefficients and use GFS (Global Forecast System) model to obtain atmospheric temperature profiles. Atmospheric corrections reduce varianc…
The CMS detector is designed around a large 4 T superconducting solenoid, enclosed in a 12000-tonne steel return yoke. A detailed map of the magnetic field is required for the accurate simulation and reconstruction of physics events in the CMS detector, not only in the inner tracking region inside the solenoid but also in the large and complex structure of the steel yoke, which is instrumented with muon chambers. Using a large sample of cosmic muon events collected by CMS in 2008, the field in the steel of the barrel yoke has been determined with a precision of 3 to 8% depending on the locatio…
Observation and research on cosmic ray muons and solar modulation effect based on plastic scintillator detector
本研究利用双端符合塑料闪烁体探测器开展了为期三个月的宇宙线缪子观测，揭示了缪子计数率的周日变化规律及其与太阳调制效应的关联，并通过羊八井观测站数据交叉验证了探测系统的可靠性。
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