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The current operation of the Resistive Plate Chamber (RPC) system within the CMS experiment involves approximately 95% tetrafluoroethane (C 2 H 2 F 4 , TFE). However, in response to climate change concerns, the European Union has instituted a ban on TFE owing to its elevated Global Warming Potential (GWP), resulting in an associated increase in market prices. In this framework, shared endeavors within the RPC EcoGas@GIF++ Collaboration, have been dedicated to investigating novel ecological gaseous mixtures based on tetrafluoropropene (C 3 H 2 F 4 , HFO-1234ze) to ensure the sustainable functionality of RPCs. This presentation will delve into the performance outcomes derived from improved RPC gas gaps operating on HFO/CO 2 -based mixtures as ecologically viable alternatives, particularly in anticipation of the High Luminosity LHC phase (HL-LHC). Additionally, the utilization of TFE/CO 2 mixtures will be explored as a pragmatic strategy to swiftly alleviate gas-related operational costs. [ABSTRACT FROM AUTHOR]

In anticipation of the High Luminosity LHC, an extensive upgrade is underway for the CMS Muon system to ensure its optimal performance in muon triggering and reconstruction. The indispensable role of Resistive Plate Chambers (RPC) as dedicated muon detectors stems from their exceptional timing resolution. To meet the requirements of Phase-II of the LHC, the RPC system will be expanded up to a pseudorapidity of 2.4. The forward Muon system's upcoming RE3/1 and RE4/1 stations will feature improved Resistive Plate Chambers (iRPC). Distinguished by a unique design and geometry, including a 2D strip readout, these iRPCs represent a significant advancement over the current RPC system. The enhancements include the use of thinner electrodes, a narrower 1.4 mm gas gap, and improved Front-End Board (FEB) allowing a 30 fC threshold. Two iRPC chambers were installed in station 3 of CMS during the year end technical stop (YETS) 2023/2024 and other 70 are being assembled at CERN and being prepared for installation next YETS 2024/2025. This paper provides a comprehensive summary of quality control (QC) and future plans for iRPC chambers in CMS detector. [ABSTRACT FROM AUTHOR]

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]

The ALICE Muon IDentifier is composed of 72 single-gap bakelite Resistive Plate Chambers, which have been operational since 2009 in avalanche mode with a Tetrafluoroethane/Isobutane/Sulphur Hexafluoride gas mixture, undergoing counting rates of the order of tens of Hz/cm 2. Here, the long-term performance and stability of the RPC system will be discussed, in terms of efficiency, dark current and dark rate. An assessment of potential signs of ageing observed in the detectors will be presented, together with a summary of the most common hardware problems experienced. [ABSTRACT FROM AUTHOR]

Resistive Plate Chambers (RPCs) are gaseous detectors widely used in high energy physics experiments, operating with a gas mixture primarily containing Tetrafluoroethane (C 2 H 2 F 4), commonly known as R-134a, which has a global warming potential (GWP) of 1430. To comply with European regulations, the RPC EcoGas@GIF++ collaboration, involving ALICE, ATLAS, CMS, LHCb/SHiP, and EP-DT communities, has undertaken intensive R&D efforts to explore new environmentally friendly alternative gas mixtures for RPC technology. A leading alternative under investigation is HFO1234ze, boasting a low GWP of 6 and demonstrating reasonable performance compared to R-134a. Over the past few years, RPC detectors with slightly different characteristics and electronics have been studied using HFO and CO 2 -based gas mixtures at the CERN Gamma Irradiation Facility. An aging test campaign was launched in August 2022, and during the latest test beam in July 2023, all detector systems underwent evaluation. This contribution will report the results of the aging studies and the performance evaluations of the detectors with and without irradiation. [ABSTRACT FROM AUTHOR]

ALICE (A Large Ion Collider Experiment) studies the Quark-Gluon Plasma (QGP): a deconfined state of nuclear matter obtained in ultra-relativistic heavy-ion collisions. One of the key probes for QGP characterization is the study of quarkonia and open heavy flavor production, of which ALICE exploits the muonic decay. In particular, a set of Resistive Plate Chambers (RPCs), placed in the forward rapidity region of the ALICE detector, is used for muon identification purposes. The correct operation of these detectors is ensured by the choice of the proper gas mixture. Currently they are operated with a mixture of C 2 H 2 F 4 , i-C 4 H 10 and SF 6 but, starting from 2017, new EU regulations have enforced a progressive phase-out of C 2 H 2 F 4 because of its large Global Warming Potential (GWP), which is making it difficult and costly to purchase. Moreover, CERN asked LHC experiments to reduce greenhouse gases emissions, to which RPC operation contributes significantly. A possible candidate for C 2 H 2 F 4 replacement is the C 3 H 2 F 4 (diluted with other gases, such as CO 2), which has been extensively tested using cosmic muons. Promising gas mixtures have been devised; the next crucial steps are the detailed in-beam characterization of such mixtures as well as the study of their performance under increasing irradiation levels. This contribution will describe the methodology and results of beam tests carried out at the CERN Gamma Irradiation Facility (equipped with a high activity 137Cs source and muon beam) with an ALICE-like RPC prototype, operated with several mixtures with varying proportions of CO 2 , C 3 H 2 F 4 , i-C 4 H 10 and SF 6. Absorbed currents, efficiencies, prompt charges, cluster sizes, time resolutions and rate capabilities will be presented, both from digitized (for detailed shape and charge analysis) and discriminated (using the same front-end electronics as employed in ALICE) signals. [ABSTRACT FROM AUTHOR]

The standard gas mixture for the Resistive Plate Chambers (RPC), composed of C 2 H 2 F 4 /i- C 4 H 10 / SF 6 , allows the detector operation in avalanche mode, as required by the high-luminosity collider experiments. The C 2 H 2 F 4 and SF 6 are now considered to be non-eco-friendly gases for their high Global Warming Potential (GWP). These gases are not recommended for industrial uses anymore, thus their availability will be increasingly difficult over time and the search for an alternative gas mixture is then of absolute priority. There are several studies on going which use different approach to find an alternative gas mixture suitable for experiment which work in high-radiation environment, as those operating at the Large Hadron Collider (LHC). One approach is to replace the standard gas with HFO1234ze/ CO 2 /i- C 4 H 10 / SF 6 , being the HFO1234ze/ CO 2 the main gas component and obtaining a gas mixture with a GWP ∼ 200. The second approach, currently under study by ATLAS and CMS collaborations, is to introduce a small fraction of CO 2 in the standard gas mixture, thus reducing the emissions of C 2 H 2 F 4 . In this presentation the results on the performance achieved using a 1 mm gas gap RPC with both types of gas mixtures are reported. Moreover, the possibility to reduce the SF 6 fraction and to replace it at all with a new gas, the HFO1233zd, is also reported. The RPC performance are studied under strong photon irradiation which reproduces the gamma background of the ATLAS cavern and that expected during the High-Luminosity phase of the LHC. [ABSTRACT FROM AUTHOR]

A novel type of resistive plate chamber, based on diamond-like carbon (DLC) electrodes is under development for background identification in the MEG II experiment. The DLC-RPC is required to have a radiation hardness to mass irradiation since it is planned to be placed in a high-intensity and low-momentum muon beam. In this study, the aging test using a high-intensity X-ray beam was conducted to evaluate the radiation hardness of the DLC-RPC. The accumulated charge due to X-ray irradiation reached about 54 C/ cm 2 , which is approximately half of the one-year irradiation dose expected in the MEG II experiment. As a result, the degradation of the gas gain was observed due to fluorine deposition and insulators formed on the DLC electrodes. In addition, discharges via spacers were also observed repeatedly and interrupted the DLC-RPC operation. [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]

An efficient and safe gas mixture recirculation system for Resistive Plate Chambers (RPCs) detector is a crucial item for planning any future application. The system is based on a special valve that decouples a suction pump from the RPC, with the aim to keep the pressure inside the chamber in the range from 1 mbar to 3 mbar, regardless of variations in atmospheric pressure, recirculated flow, and temperature. The circulating gas is flushed in pure water where the impurities developed inside the detector are expected to be soluble and trapped. [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]

The standard gas mixture for the Resistive Plate Chambers (RPC), composed of C 2 H 2 F 4 /i- C 4 H 10 / SF 6 , allows the detector operation in avalanche mode, as required by the high-luminosity collider experiments. The gas density, the low total charge delivered inside the gas and the comfortable avalanche-streamer separation guarantee high detection efficiency, rate capability and slow detector aging. The standard RPC gas mixture is mostly based on Hydrofluorocarbons, HFCs, extensively used in the refrigeration industry. The Hydrofluorocarbons are now considered to be non-eco-friendly gases for their high Global Warming Potential (GWP). The SF 6 has the largest GWP, 22 900, but, due to its low concentration, it contributes only with few tens of units to the total value. The major contribution comes from the main standard gas mixture component, the C 2 H 2 F 4 (GWP ≈ 1300). These gases are not recommended for industrial uses anymore, thus their availability will be increasingly difficult over time and the search for an alternative gas mixture with low-GWP is then of absolute priority within the RPC community. We report the performance of the RPC working with new environment-friendly gases which could replace the standard mixture. In this work the standard mixture main component, the C 2 H 2 F 4 , is replaced by a proper mixture of CO 2 (GWP = 1) and Tetrafluoropropene ( C 3 H 2 F 4 , GWP ≈ 6). The other high-GWP component, the SF 6 , is replaced by a molecule, the Chloro-Trifluoropropene ( C 3 H 2 ClF 3 , GWP ≈ 5) never tested in RPC detectors. The mixtures studied have a total GWP ≈ 10. We report, for several eco-gas mixtures, the detection efficiency, streamer probability, electronic and ionic charge as a function of the high voltage. Moreover, the timing properties are studied and the detector time resolution is measured. We also focus the attention on a new category of signals having intermediate properties between avalanche and streamer, called "transition events". This category is negligible for the standard gas mixture but relevant for HFO/ CO 2 -based gas mixtures. We show a direct comparison between SF 6 and C 3 H 2 ClF 3 to study in depth the possibility to replace the SF 6. [ABSTRACT FROM AUTHOR]

A new generation of gaseous particle detectors named Resistive Cylindrical Chamber (RCC) (Cardarelli, 2021; Rocchi, 2022) [1,2] has been developed to overcome the limitations of Resistive Plate Chambers (Santonico and Cardarelli, 1981) [3] and broaden their application range. The principle behind this new technology consists in the transition from a planar to a cylindrical geometry while maintaining an almost planar electric field. The cylindrical structure of the electrodes allows to reach the following goals: increase the gas pressure to improve the intrinsic efficiency of the detector even for thin gas gaps or light gas mixtures; design the detector in order to produce an electric field gradient possibly useful to contain the development of the avalanche discharge. These features could lead to design detectors of simple mechanical realization with time resolution comparable with that of MRPCs maintaining a high efficiency of detection on a single thin gas-gap. The device pressurization could also allows to use new gases in view of the transition to eco-friendly gas. [ABSTRACT FROM AUTHOR]

Resistive Plate Chamber detectors are largely used in current High Energy Physics experiments, typically operated in avalanche mode with large fractions of Tetrafluoroethane (C2H2F4), a gas recently banned by the European Union due to its high Global Warming Potential (GWP). An intense R&D activity is ongoing to improve RPC technology in view of future HEP applications. In the last few years the RPC EcoGas@GIF++ Collaboration has been putting in place a joint effort between the ALICE, ATLAS, CMS, LHCb/SHiP and EP-DT Communities to investigate the performance of present and future RPC generations with eco-friendly gas mixtures. Detectors with different layout and electronics have been operated with ecological gas mixtures, with and without irradiation at the CERN Gamma Irradiation Facility (GIF++). Results of these performance studies together with plans for an aging test campaign are discussed in this article. [ABSTRACT FROM AUTHOR]

We present a study of the response of the highly granular Digital Hadronic Calorimeter with steel absorbers, the Fe-DHCAL, to positrons, muons, and pions with momenta ranging from 2 to 60 GeV/c. Developed in the context of the CALICE collaboration, this hadron calorimeter utilises Resistive Plate Chambers as active media, interspersed with steel absorber plates. With a transverse granularity of 1 × 1 cm2 and a longitudinal segmentation of 38 layers, the calorimeter counted 350,208 readout channels, each read out with single-bit resolution (digital readout). The data were recorded in the Fermilab test beam in 2010–11. The analysis includes measurements of the calorimeter response and the energy resolution to positrons and muons, as well as detailed studies of various shower shape quantities. The results are compared to simulations based on Geant4 , which utilise different electromagnetic and hadronic physics lists. [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]

For the High Luminosity (HL-LHC) upgrade an upgrade of the CMS detector is foreseen. One of the main projects is the development of the improved Resistive Plate Chamber (iRPC) detectors that will be installed in the forward region of CMS. To validate the performance of the new detector gaps with HL-LHC radiation levels, experimental tests have been conducted at the CERN Gamma Irradiation Facility (GIF++). One chamber equipped with electronics is studied and its parameters are monitored as a function of the accumulated charge. [ABSTRACT FROM AUTHOR]

A known volume of air is injected into or aspirated from a sealed vessel. In the ideal gas approximation, the corresponding vessel deformation is measurable. The linear correlation between pressure and deformation in the measurements carried out demonstrates the vessel's elastic response. Measurements of several RPC gas volumes are reported. Different expansion and compression slopes of pressure vs volume plots, highlight a structure problem, for example, unglued spacers. Defective stiffness values of the electrode materials are also highlighted by anomalous slope values. [ABSTRACT FROM AUTHOR]

Resistive Plate Chambers (RPCs) are essential active media of large-scale experiments as part of the muon systems and (semi-)digital hadron calorimeters. Among the several outstanding issues associated with the RPCs, the loss of efficiency for the detection of particles when subjected to high particle fluxes, and the limitations associated with the common RPC gases can be listed. In order to address the latter issue, we developed novel RPC designs with special anode plates coated with high secondary electron emission yield materials such as Al 2 O 3 and TiO 2. The proof of principle was obtained for various designs and is in progress for the rest. The idea was initiated following the achievements on the development of the novel 1-glass RPCs. Here we report on the construction of various different RPC designs, and their performance measurements in laboratory tests and with particle beams; and discuss the future test plans. [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]

Thin-gap Resistive Plate Chambers (RPCs) with a 1 mm gap size are introduced in the ATLAS Phase-II upgrade. Smaller avalanche charge due to the reduced gap size raises concerns for signal integrity. This work focuses on the RPC signal propagation process in lossless conditions, and an analytical study is implemented for the ATLAS RPC. Detector modeling is presented, and the simulation of the RPC signal is discussed in detail. Simulated characteristic impedance and crosstalk have been compared with the measured value to validate this model. This method is applied to different RPC design geometries, including the newly proposed η − η readout scheme. [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]

An optimized design of a neutron detector based on timing RPCs (Resistive Plate Chambers) with boron-10 neutron converters is presented. The detector is composed of a stack of ten double gap RPCs with aluminium cathode plates coated on both sides with 10B 4 C. This design enables simultaneous determination with high accuracy of both the neutron time-of-flight (down to ns resolution) and the interaction position in 3D (down to 0.25 mm resolution across and ∼ 1 mm along the beam). It is shown that the detection efficiency can approach 60% for neutrons with lambda = 4.7 Å. A new geometry with less material budget is introduced for the signal pick-up strip arrays. The results of simulation-based optimization of the design are reported considering the trade-off between the detection efficiency, the count rate capability and the amount of elastic scattering on the detector components. [ABSTRACT FROM AUTHOR]

Time resolution and efficiency of single-gap ( 300 μ m ) multi-strip timing resistive plate chambers (tRPC) have been investigated using 136 Xe ions accelerated at 560 A MeV with different rates. A time resolution of 37 ps (standard deviation) has been achieved for an irradiation rate of 12 Hz ∕ cm 2 . The tRPC also provides a detection efficiency above 98%. Our results show that an increase of the irradiation rate clearly leads to a degradation of the time resolution and a quenching of the signal charge. [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]

Driven by the recent improvement in additive manufacturing technologies, we designed a detector that can be fully printed with a standard and commercial 3D printer. The main goals of this research concern the marginal design and construction costs, the reproducibility/modularity of the products, and the reduced assembly time. During the first phase of this research, after determining the most suitable material, we produced 10 examples of detector. [ABSTRACT FROM AUTHOR]

Abstract: The Resistive Plate Chambers are used in CMS as dedicated muon trigger detectors in both barrel and endcap regions. They also contribute to the identification, reconstruction and tracking of the muons, together with Drift Tubes in the barrel and Cathode Strip Chambers in the endcaps. In this paper a detailed report about the operation and performance of the system after three years of LHC activities with increasing instantaneous luminosity is given. This period allowed to accumulate enough statistics to measure the detector performance with an unprecedented accuracy on such a large amount of chambers. This provided new insights both on the detector fundamentals and on the related operational aspects. Special attention was devoted to the working point calibration procedures and to the stability of the system. A comparison between the initial and present performance is made, and an overview is given of what has been learned in almost three years of operation of one of the largest systems based on RPCs. [Copyright &y& Elsevier]

Abstract: The ARGO-YBJ experiment at 4300m above sea level on the Tibet plateau is a full-coverage array of Resistive Plate Chambers (RPCs) operated in streamer mode, covering a surface of 74×78m2 surrounded by a guard ring. It was designed to detect extensive air showers generated by primary cosmic rays in the energy range from a few hundred GeV up to about 1PeV. It has been running uninterruptedly with its complete layout since October 2007, providing results in astrophysics and cosmic-ray physics. Some of the main results obtained by ARGO-YBJ in the study of TeV rays from Supernova Remnants and from Active Galactic Nuclei and in the study of the medium-scale cosmic-ray anisotropy will be described. We also discuss the results of a test which proves the feasibility of the control procedure devised to stabilize the response of the detector. [Copyright &y& Elsevier]

Abstract: The performance of Multigap Resistive Plate Chambers (MRPCs) with pure Freon 134a was investigated. Two types of MRPCs with different number of gaps and different gap width have been studied; one with 10 gaps of and the other with 24 gaps of . From the beam tests performed at CERN, the time resolution of the MRPCs flushed with pure Freon has been found to be the same as when SF6 was added to Freon. The 10 gap MRPC has a time resolution better than 50ps and the 24 gap MRPC has a resolution of 21ps, at full efficiency and with no streamers. With pure Freon, the streamers start to develop at a lower electric field. [ABSTRACT FROM AUTHOR]

Abstract: We have simulated the gas avalanche in a multigap resistive plate chamber (MRPC). The results were then compared with our data from the MRPC . Up to now, the total amount of charge produced in a gas gap is considered to be given by the total number of positive ions generated by the gas avalanches. However, the total charge generated by the simulation program is much too large and is in conflict with our data. Our data indicate that nearly 100% of the negative ions recombine with the positive ions. The recombination effect dramatically reduces the amount of charge in the gas gap: a very important feature for MRPC technology especially for the rate capability. [Copyright &y& Elsevier]

Abstract: We present a pulse generator able to generate pulses statistically similar to the ones produced by RPC cells. The device generates up to four arrays of fast and narrow random-like pulses. Polarity, maximum amplitudes, widths and pulse rate in each channel may be modified independently in order to simulate different RPC setups and environments. This portable and cost-effective pulse generator is a versatile instrument for testing FE-Electronics and different real detector features related with the signal propagation inside the detector. It has been developed in the framework of the ESTRELA 1 [1] ESTRELA (Electrically Shielded Timing RPC Ensemble for Low Angles) is part of the upgrade of the HADES experiment at GSI with the aim of constructing an RPC-based time-of-flight wall that will cover around 8m2 in order to cope with the high particle multiplicities expected for heavy nuclei collision systems such as Au+Au. project of the HADES experiment at GSI. [Copyright &y& Elsevier]

Abstract: India-based Neutrino Observatory (INO) collaboration is proposing to build a 50kton magnetised iron calorimetric (ICAL) detector in an underground laboratory to be located in South India. Glass resistive plate chambers (RPCs) of about 2m×2m in size will be used as active elements for the ICAL detector. As a first step towards building the ICAL detector, a 35ton prototype of the same is being set up over ground to track cosmic muons. Design and construction details of the prototype detector and its data acquisition system will be discussed. Some of the preliminary results from the detector stack will also be highlighted. [Copyright &y& Elsevier]

Abstract: The India-based Neutrino Observatory (INO) collaboration is planning to build a massive 50kton magnetised Iron Calorimeter (ICAL) detector, to study atmospheric neutrinos and to make precision measurements of the parameters related to neutrino oscillations. Glass Resistive Plate Chambers (RPCs) of about 2m×2m in size are going to be used as active elements for the ICAL detector. We have fabricated a large number of glass RPC prototypes of 1m×1m in size and have studied their performance and long term stability. In the process, we have developed and produced a number of materials and components required for fabrication of RPCs. We have also designed and optimised a number of fabrication and quality control procedures for assembling the gas gaps. In this paper we will review our various activities towards development of glass RPCs for the INO ICAL detector. We will present results of the characterisation studies of the RPCs and discuss our plans to prototype 2m×2m sized RPCs. [Copyright &y& Elsevier]

Abstract: The ARGO-YBJ array for EAS detection at high altitude (4300m a.s.l.) is the largest RPC-based detector in operation at present (active area of out of a total instrumented surface of about ). The constant monitoring of the main operational and environmental parameters is essential for both keeping the detector status under control and understanding the detector behaviour more deeply. Exploiting the information provided by the ARGO-YBJ Detector Control System, the present status of the detector is described and some correlations between the environmental and the operational parameters of the ARGO-YBJ RPCs are shown. This study was performed using the monitored data from the complete ARGO-YBJ array which has been in operation since October 2007. Preliminary results on the observations of the Moon shadow and of -ray point sources are also presented. [Copyright &y& Elsevier]

Abstract: The HARP resistive plate chamber (RPC) system was designed for time-of-flight measurement in the large-angle acceptance region of the HARP spectrometer. It comprised 46 four-gap glass RPCs covering an area of . The design of the RPCs, their operation, intrinsic properties, and system performance are described. The intrinsic time resolution of the RPCs is 127ps leading to a system time-of-flight resolution of 175ps. It is argued that gross differences between pion and proton timing in multi-gap timing RPCs, reported recently in the literature, do not exist. [Copyright &y& Elsevier]

Single gap Resistive Plate Chamber (RPC) is one of the very popular gaseous detectors used in high-energy physics experiments nowadays. It is a very fast detector having low cost of fabrication. The RPCs are usually built using glass or bakelite plates having high resistivity ∼ 1 0 10 – 1 0 11 Ω cm. Bakelite RPCs are generally fabricated with a linseed oil coating inside to make the inner electrode surface smoother which helps to reduce the micro discharge probability. Linseed oil coating also reduces the surface UV sensitivity dramatically and effectively protect the bakelite surfaces from the Hydrofluoric Acid (HF), produced by the interaction of fluorine with the water vapour. There is a conventional way to do this linseed oil coating after making the gas gap as done in experiments e. g. ALICE, CMS etc. A new technique is introduced here to do the linseed oil coating on the bakelite plate before making the gas gap. 100% Tetrafluoroethane (C 2 H 2 F 4) gas is used to test the RPC module in the avalanche mode with cosmic rays. Conventional NIM electronics is used for this study. The efficiency and noise rate are measured. In this article, the detailed method of fabrication and the first test results are presented. [ABSTRACT FROM AUTHOR]

In this work, we present a comprehensive method to measure the gas parameters, such as the effective Townsend coefficient and electron drift velocity in homogeneous high electric fields (up to 100 kV/cm) at atmospheric pressure and room temperature. A pulsed laser facility with micro-meter spatial accuracy and picosecond pulse duration is used to ignite primary ionizations at specific positions in the gas gap of a Resistive Plate Chamber (RPC) detector prototype. The gas parameters are determined solely by the RPC signals. The main component of the current standard gas for RPC is Tetrafluoroethane (R134a) which has a high Global Warming Potential. Therefore, using Tetrafluoropropene (HFO-1234ze) is under research as an eco-friendly substance. We measure the parameters of these two types of working gases. It is the first direct measurement of the gas parameters of timing RPCs under working conditions. By comparison with existing data from other investigation points, we observe a dependence of gas parameters on the pressure. [ABSTRACT FROM AUTHOR]

Abstract: Resistive Plate Chambers (RPCs) are being developed for use in a hadron calorimeter with very fine segmentation of the readout. The design of the chambers and various tests with cosmic rays are described. This paper reports on the measurements with multi-bit (or analog) readout of either a single larger or multiple smaller readout pads. [Copyright &y& Elsevier]

Abstract: Hadron Outer (HO) scintillators located around the CMS coil are sensitive to muons. They can be used in coincidence with RPC chambers for the Muon Trigger. This paper contains a brief description of the two systems and the proposal of how they can be integrated. Backgrounds, efficiencies, and trigger rates have been calculated. The conclusion is that rate reduction factors as high as 100 can be obtained for efficiency. [Copyright &y& Elsevier]

We have investigated the operation of the multigap resistive plate chamber (MRPC) for the ALICE-TOF system with a gas mixture free of flammable components. Two different gas mixtures, with and without iso-C4H10 have been used to measure the performance of the MRPC. The efficiency, time resolution, total charge, and the fast to total charge ratio have been found to be comparable. [Copyright &y& Elsevier]

A big advance in resistive plate chamber technology happened in 1996 with the advent of the multigap resistive plate chamber (MRPC). The MRPC allows us to easily construct detectors with many small gas gaps and thus we obtain good timing together with high detection efficiency. Using this technology, it is now common to build detectors with gas gaps of 200–300 μm in width. This paper examines space-charge limited avalanche growth; this becomes a dominant effect for narrow gap resistive plate chambers. This effect controls gas gain and explains the reason for the excellent behaviour of MRPCs built with this gas gap. [Copyright &y& Elsevier]

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]

All the CMS muon stations will be equipped with Resistive Plate Chambers (RPCs). They will be exposed to high neutron background environment during the LHC running. In order to verify the safe operation of these detectors, an irradiation test has been carried out with two RPCs at high neutron flux (about 108 n cm−2 s−1), integrating values of dose and fluence equivalent to 10 LHC-years. Before and after the irradiation, the performance of the detectors was studied with cosmic muons, showing no relevant aging effects. Moreover, no indication of damage or chemical changes were observed on the electrode surfaces. [Copyright &y& Elsevier]

The trigger for the Dimuon Forward Spectrometer of the forthcoming ALICE experiment at CERN LHC will be provided by low-resistivity, single gap Resistive Plate Chambers working in streamer mode.Different ageing test were performed to measure and improve the life-time of the detector. Dummy chambers have been built to understand the effects of continuous gas flow upon the Bakelite resistivity: the results concerning our standard gas mixture (49% Ar, 40% forane, 7% isobutane and 4% SF6) are reported, and compared with the same mixture in which ∼1% of water vapor is added. Moreover, two ageing test of 1 month each have been carried out at the Gamma Irradiation Facility at CERN during 2001. The efficiency for cosmic rays under γ irradiation of RPCs coated with different thicknesses of linseed oil was measured. After protracted operation, the detectors have shown an increase of the current and of the background rate. The increase is slower in the chamber with a thicker oil coating. [Copyright &y& Elsevier]

For the identification of particles in the momentum range 0.5 to 2.5 GeV/c the ALICE experiment uses a time of flight array. The detectors used are Multigap Resistive Plate Chambers (MRPC) with 50 ps time resolution. The whole array covers a ∼150 m2 area and consists of detector elements in the form of MRPC strips. To cope with the high multiplicity expected for heavy ion collisions, the TOF array is segmented; pickup pads of 2.5×3.5 cm2 are used. Thus the whole system will have 160 000 read-out channels. Here we present results of the R&D program of the last 3 years, which led to the design of the final TOF system for ALICE. [Copyright &y& Elsevier]

The BaBar Collaboration has operated an instrumented flux return (IFR) system covering over 2000 m2 with resistive plate chambers (RPCs) for nearly 3 years. The chambers are constructed of bakelite sheets separated by 2 mm. The inner surfaces are coated with linseed oil. This system provides muon and neutral hadron detection for BaBar. Installation and commissioning were completed in 1998, and operation began mid-year 1999. While initial performance of the system reached design, over time, a significant fraction of the RPCs demonstrated significant degradation, marked by increased currents and reduced efficiency. A coordinated effort of investigations have identified many of the elements responsible for the degradation. This article presents our current understanding of the aging process of the BaBar RPCs along with the action plan to combat performance degradation of the IFR system. [Copyright &y& Elsevier]

This report describes in broad outline the development of RPC detectors from the beginning up to the RPC 2001 Workshop. Two specific RPC problems connected with the long-term electrical polarization of electrode materials and freon-based gas mixtures are noted. Typical parameters of modern RPCs used in streamer-spark and avalanche modes are given. Brief information about all large RPC detectors for physics is presented. [Copyright &y& Elsevier]