Search

A new readout technique was developed with the primary aim of keeping the number of channels in the front-end electronics as low as possible when scaling up the sensitive area of a Resistive Plate Chamber (RPC). The readout method here presented significantly reduces the dependence between the detector area and the number of electronic channels, without substantial reduction of its performance: a 30 × 30 cm 2 double stack multi-gap timing RPC was operated during weeks with cosmic rays, achieving a 2D spatial resolution well below 1 mm and time resolution lower than 100 ps, while its efficiency was kept above 98%. [ABSTRACT FROM AUTHOR]

In view of the High Luminosity upgrade of the CERN LHC, the forward CMS Muon spectrometer will be extended with two new stations of improved Resistive Plate Chambers (iRPC) covering the pseudorapidity range from 1.8 to 2.4. Compared to the present RPC system, the gap thickness is reduced to lower the avalanche charge, and an innovative 2D strip readout geometry is proposed. These improvements will allow iRPC detector to cope with higher background rates. A new Front-End-Board (FEB) is designed to readout iRPC signals with a threshold as low as 30 fC and an integrated Time Digital Converter with a resolution of 30 ps. In addition, the communication bandwidth is significantly increased by using optical fibers. The history, final design, certification, and calibration of this FEB are presented. [ABSTRACT FROM AUTHOR]

In view of the High Luminosity LHC, the CMS Muon system will be upgraded to sustain its efficient muon triggering and reconstruction performance. Resistive Plate Chambers (RPC) are dedicated detectors for muon triggering due to their excellent timing resolution. The RPC system will be extended up to 2.4 in pseudorapidity. Before the LHC Long Shutdown 3, new RE3/1 and RE4/1 stations of the forward Muon system will be equipped with improved Resistive Plate Chambers (iRPC) having, compared to the present RPC system, a different design and geometry and 2D strip readout. This advanced iRPC geometry configuration allows the rate capability to improve and hence survive the harsh background conditions during the HL-LHC phase. Several iRPC demonstrator chambers were installed in CMS during the recently completed 2nd Long Shutdown to study the detector behaviour under real LHC conditions. This paper summarizes the iRPC project and its schedule, including the status of the iRPC production sites, details of the chamber quality control procedures and results of the commissioning of the demonstrator chambers. [ABSTRACT FROM AUTHOR]

Muon tomography is one of several fields of applied physics that have witnessed the successful use of particle detection based on Resistive Plate Chambers (RPC). In this work, we report on an innovative project concerning transmission muography for geological characterization. For this purpose, a muon telescope built of four RPC planes was mounted on an adjustable structure and the telescope's response to atmospheric muons was studied. Data acquisition campaigns took place at different locations for producing muographic images of the building of the Physics Department of the University of Coimbra, in Portugal. More recently, the detector was moved to an underground gallery of an old mine, where it is taking data that is being assessed in combination with the results from conventional geophysics techniques. [ABSTRACT FROM AUTHOR]

We are developing time-of-flight (TOF) multi-gap Resistive Plate Chambers (MRPCs) which perform both timing and hit position measurements, the TOF-tracker MRPC, for muon detection to measure exclusive Drell–Yan reaction ( π − p → γ ∗ n → μ + μ − n) at J-PARC's hadron hall. Here we report on the development of a prototype TOF-tracker MRPC with a sensitive area of 500 × 1000 mm 2 and its performance in an electron-positron particle beam at the SPring-8 synchrotron in Japan. • Development of the muon detector for both timing and hit position measurements. • Beam test for examination of the basic performance the muon detector. • Achievement of a time resolution of 100 ps. [ABSTRACT FROM AUTHOR]

The muon system of the CERN Compact Muon Solenoid (CMS) experiment includes more than a thousand Resistive Plate Chambers (RPC). They are gaseous detectors operated in the hostile environment of the CMS underground cavern on the Large Hadron Collider where pp luminosities of up to 2 × 1 0 34 cm − 2 s − 1 are routinely achieved. The CMS RPC system performance is constantly monitored and the detector is regularly maintained to ensure stable operation. The main monitorable characteristics are dark current, efficiency for muon detection, noise rate etc. Herein we describe an automated tool for CMS RPC current monitoring which uses Machine Learning techniques. We further elaborate on the dedicated generalized linear model proposed already and add autoencoder models for self-consistent predictions as well as hybrid models to allow for RPC current predictions in a distant future. [ABSTRACT FROM AUTHOR]

With the HL-LHC upgrade of the LHC machine, an increase of the instantaneous luminosity by a factor of five is expected and the current detection systems need to be validated for such working conditions to ensure stable data taking. At the CERN Gamma Irradiation Facility (GIF++) many muon detectors undergo such studies, but the high gamma background can pose a challenge to the muon trigger system which is exposed to many fake hits from the gamma background. A tracking system using RPCs is implemented to clean the fake hits, taking profit of the high muon efficiency of these chambers. This work will present the tracking system configuration, used detector analysis algorithm and results. [ABSTRACT FROM AUTHOR]

A muon telescope equipped with four multi-gap Resistive Plate Chambers of 2 m2 per plane was tested with the muon scattering tomography technique. The telescope was operated during several hours with high atomic number materials located at its center with two detector planes on each side. With an intrinsic efficiency above 98%, spatial resolution around 1 cm and detector planes spaced by 45 cm, it was possible to identify the presence of a 5 cm thick tungsten block in 10 min of acquisition. The results obtained after five hours of acquisition are also presented in this communication. [ABSTRACT FROM AUTHOR]

In view of the High-Luminosity LHC (HL-LHC) phase, the Resistive Plate Chambers (RPC) system of the Compact Muon Solenoid (CMS) experiment will be extended by installing a new generation of improved-RPC. In the present study, a GEANT4 Monte Carlo simulation study has been done to estimate the background rate on the iRPCs expected in the future runs of HL-LHC. • CMS improved-RPC (iRPC) for the muon system upgrade. • GEANT4 simulation for the iRPC sensitivity study. • Estimation of the iRPCs background rate during HL-LHC. [ABSTRACT FROM AUTHOR]

Abstract: Particle Flow Algorithms (PFAs) have been proposed as a method of improving the jet energy resolution of future colliding beam detectors. PFAs require calorimeters with high granularity to enable three-dimensional imaging of events. The Calorimeter for the Linear Collider Collaboration (CALICE) is developing and testing prototypes of such highly segmented calorimeters. In this context, a large prototype of a Digital Hadron Calorimeter (DHCAL) was developed and constructed by a group led by Argonne National Laboratory. The DHCAL consists of 52 layers, instrumented with Resistive Plate Chambers (RPCs) and interleaved with steel absorber plates. The RPCs are read out by 1 x 1cm2 pads with a 1-bit resolution (digital readout). The DHCAL prototype has approximately 480,000 readout channels. This talk reports on the design, construction and commissioning of the DHCAL. The DHCAL was installed at the Fermilab Test Beam Facility in fall 2010 and data was collected through the summer 2011. [Copyright &y& Elsevier]

Abstract: The Digital Hadron Calorimeter (DHCAL) is a large prototype of an imaging calorimeter using Resistive Plate Chambers (RPCs) as active media. The readout is segmented into 1×1cm2 pads, each with a single bit resolution, hence the denomination of digital. The total channel count is close to 500,000. The DHCAL construction and assembly was completed in fall 2010, followed by a series of test beam campaigns in the FTBF test beam at Fermilab. In this paper we report on the analysis of events collected with the broadband muon beam. These events are utilized to geometrically align the layers horizontally and vertically, to establish the response as function of position on a single readout pad, and to measure the performance characteristics of the RPCs, i.e. the efficiency and average pad multiplicity. The latter were measured in both ‘clean’ regions of the detector, i.e. away from structures such as the rims of the chambers, and as function of position on the entire vertical plane. In addition, the paper reviews the preliminary measurements of the noise rate in the detector. [Copyright &y& Elsevier]

The resistive plate chambers (RPCs) muon trigger electronics of the Compact Muon Solenoid (CMS) detector performs a number of tasks: synchronization of detector signals, optical data transmission from the detector to the trigger electronics, pattern recognition, muons momentum measurement, selection of track candidates. For the diagnostic purposes, as well as for the calibration and real-time monitoring of the RPC detectors and electronic hardware, a set of flexible diagnostic modules was designed and implemented into the field programmable gate arrays on which the trigger electronics is based. These include: multichannel counters, timing histograms, test pulses generators, diagnostic readout and data spying ("snap-shots" of the data stream). Test results presented in this paper, including tests with Large Hadron Collider-like muon beam, illustrate the performance and the usefulness of these diagnostic modules [ABSTRACT FROM PUBLISHER]

The STAR experiment at RHIC plans to implement a 60 m2 Time-of-Flight (TOF) system. The Multigap Resistive Plate Chamber (MRPC) is a suitable candidate for the STAR TOF system due to its time resolution of order of 60 ps with efficiencies in excess of 97%. We obtained this result with modules composed of 6 gas gaps of 220 μm and pad area of 20 cm2. In this paper, we report on the performance of this MRPC module and present the current status of the construction and installation into STAR of a prototype tray. [Copyright &y& Elsevier]

Resistive plate chambers (RPC) operated in streamer mode will provide the trigger of the ALICE forward muon spectrometer at the future large hadron collider at CERN. In a previous study, we had demonstrated that the time resolution of RPC in streamer mode could be improved significantly using a new discrimination technique called A DUaL Threshold (ADULT). The conclusions were based on a small sample of cosmic events, hence with almost zero incident flux, collected on a very simple test bench. The ADULT method has then been implanted in a custom integrated circuit and new data have been taken during beam and irradiation tests. The principle and the advantages of ADULT are reminded. The performances of the detector equipped with the new chip are given. [Copyright &y& Elsevier]

In the framework of an R&D program on the ALICE dimuon trigger system, the spatial resolution of Resistive Plate Chambers working in streamer mode has been investigated during beam tests. Preliminary studies with cosmic rays had evidenced a dependence of the charge profile to the high voltage and to the gas mixture. However, the spatial resolution measured from the beam tests is only slightly varying with the high voltage and is close to the expected value w/√ of 12 where w is the strip pitch, for strips of 1 and 2 cm width. The probability to fire a strip as a function of the distance from the strip to the particle impact has been measured for various high voltages. A simple parametrisation of this probability has been achieved. This allows to predict, under various working condition, the cluster size distributions for RPCs with different strip widths and also to account for the effect of the particle incident angle. [Copyright &y& Elsevier]

The compact muon solenoid (CMS) is one of the four experiments which is getting and analysing the results of the collision of protons at LHC. The CMS trigger system is divided into two stages, the level-1 trigger and high-level triggers, to handle the large stream of data produced in collision. The information transmitted from the three muon subsystems (DT, CSC and RPC) are collected by the Global Muon Trigger (GMT) Board and merged. A method for evaluating the RPC system trigger efficiency with data from pp collision was developed using the features of GMT. The results of the study with the real data of 2011 are shown and discussed here along with the comparison of Monte Carlo results. [ABSTRACT FROM AUTHOR]

Abstract: The work presented here describes the characterization of double layer, bakelite RPCs for the end-cap region of the “Compact Muon Solenoid” experiment at LHC, which were built, assembled and tested in India before their dispatch to CERN in 2008. These detectors consist of eight of RE⁎/2 and two of RE*/3 type geometry for the CMS. The RE*/2 detectors had gas-gaps made at KODEL, Korea, and the two RE*/3 detectors had gas-gaps from GT, Italy, supplied to us from the CMS spare pool. We discuss the efficiency, leakage currents, strip profile and cluster size of these detectors as has been evaluated with the cosmic hodoscope at ISR Laboratory, CERN, where all the eight RE*/2 RPCs qualified for the cosmic tests, thereby ascertaining the QA/QC procedures followed during assembly at RPC Laboratory, Nuclear Physics Division, BARC, Mumbai, which is also geared up for the RPC upscope for CMS. [Copyright &y& Elsevier]

Abstract: The muon system of the CMS (Compact Muon Solenoid) experiment at the LHC (Large Hadron Collider, Geneva-CH) consists of three gaseous detectors with complementary features: the Drift Tube Chambers (DT) in the barrel and the Cathode Strips Chambers (CSC) in the forward region provide good spatial resolution while the Resistive Plate Chambers (RPC), in both barrel and forward region, have an excellent time resolution. The measurements of these detectors are employed for triggering on muons in the hardware-based Level-1 trigger stage. In such scenario an algorithm has been developed, the Global Muon Trigger (GMT), which is in charge of collecting and merging the information provided by the three detectors and outputs muon trigger candidates (GMT candidates). The GMT candidates are henceforth transmitted to the L1 Global Trigger Logic which performs the final decision of accepting or rejecting the muon candidates. The GMT algorithm allows to trace back the detectors whose measurements have been used for each GMT candidate: such feature has been exploited in developing a method for the performance evaluation of muon trigger provided by the RPC system. [Copyright &y& Elsevier]