G. Pugliese

The CMS Barrel resistive plate chambers quality tests are performed at three different sites (Bari, Pavia and Sofia), where equivalent software and hardware tools are used. Data from the first 210 detectors are available for a comprehensive analysis. The paper describes the general experimental set-up, the test procedure and the cosmic muon test results. The muon trajectory reconstruction algorithm, used for precise studies, is presented. The criteria to accept or reject a detector are also given. The CMS final-design chambers show an average efficiency greater than 95%.

A novel version of the front-end electronics for the CMS Resistive Plate Chambers is described. It is based on a new front-end ASIC, designed and manufactured in the 0.8μm BiCMOS technology by Austria Mikro Systeme. The main improvements with respect to the previous version (Loddo et al., Proceedings of the Fourth International Workshop on Resistive Plate Chambers and related Detectors, Napoli, 15–16 October 1997) [1] concern the input impedance, the threshold uniformity and the timing performance. Simulation and test results will be shown, together with a brief description of the automatic test system for both front-end chip and board.

A model to simulate the avalanche formation process and the induced signal in a Resistive Plate Chamber is presented. A first investigation of the effects of various parameters on the performance of this detector is reported.

Endothelial dysfunction has been shown to be a critical early component of organ injury after myocardial ischemia and reperfusion. Circulating levels of adhesion molecules have been regarded as a valid index of endothelial activation. Recent reports suggest that statins, widely used in the control of hypercholesterolemia, exert a protective effect on the endothelium reflected by a reduced level of circulating adhesion molecules. In this study, the effects of preoperative simvastatin treatment, at doses equivalent to those used orally for cholesterol control, were studied on plasma levels of VCAM-1, ICAM-1, and ELAM-1. A case-control study. University hospital. Fifteen patients taking simvastatin with good control of cholesterol levels, 15 patients not responsive to the simvastatin treatment, and 15 normocholesterolemic patients (control) undergoing elective coronary artery bypass surgery. The plasma levels of VACM-1, ICAM-1, and ELAM-1 were evaluated at baseline; during cardiopulmonary bypass; and 6 hours, 24 hours, and 48 hours postoperatively. In the late postoperative samples, the plasma levels of ICAM-1 and ELAM-1 were lower in both simvastatin-treated patients compared with the control patients. No significant difference was found between the patients responsive to statin and those not responsive. Finally, no significant difference was found for VCAM-1 plasma levels between the control group and the 2 treatment groups. Pretreatment with simvastatin significantly reduces the increase of ICAM-1 and ELAM-1 after coronary artery bypass surgery, by a mechanism that seems not related to its efficacy in lowering cholesterol levels.

The formation of highly reactive compounds in the gas mixture during Resistive Plate Chambers (RPCs) operation at the CERN Gamma Irradiation Facility (GIF) is studied. Results from two different types of chambers are discussed: 50 × 50 cm2 RPC prototypes and two final CMS-RB1 chambers. The RB1 detectors were also connected to a closed loop gas system. Gas composition, possible additional impurities as well as fluoride ions have been monitored in different gamma irradiation conditions both in open and closed loop mode. The chemical composition of the RPC electrode surface has also been analyzed using an electron microscope equipped with an EDS/X-ray.

The CMS collaboration considers upgrading the muon forward region which is particularly affected by the high-luminosity conditions at the LHC. The proposal involves Gas Electron Multiplier (GEM) chambers, which are able to handle the extreme particle rates expected in this region along with a high spatial resolution. This allows to combine tracking and triggering capabilities, which will improve the CMS muon High Level Trigger, the muon identification and the track reconstruction. Intense R&D has been going on since 2009 and it has lead to the development of several GEM prototypes and associated detector electronics. These GEM prototypes have been subjected to extensive tests in the laboratory and in test beams at the CERN Super Proton Synchrotron (SPS). This contribution will review the status of the CMS upgrade project with GEMs and its impact on the CMS performance.

The status of the CMS RPC Gas Gain Monitoring (GGM) system developed at the Frascati Laboratory of INFN (Istituto Nazionale di Fisica Nucleare) is reported on. The GGM system is a cosmic ray telescope based on small RPC detectors operated with the same gas mixture used by the CMS RPC system. The GGM gain and efficiency are continuously monitored on-line, thus providing a fast and accurate determination of any shift in working point conditions. The construction details and the first result of GGM commissioning are described.

Several small single gap Resistive Plate Chambers and two RB1 CMS final stations have been exposed during the last year at the CERN Gamma Irradiation Facility to study possible long-term ageing effects. Up to now, an integrated charge of about 0.05C/(cm2gap) and 0.025 C/(cm2 gap) has been accumulated for the small RPCs and the large RB1 stations, respectively. Current, rate, fast charge and efficiency have been continuously monitored with muon beam or cosmics. Results concerning operation with a moisty mixture are also reported.

A bakelite double gap Resistive Plate Chamber (RPC), operating in avalanche mode, has been exposed to the radiation emitted from a 252Cf source to measure its neutron and gamma sensitivity. One of the two gaps underwent the traditional electrodes surface coating with linseed oil. RPC signals were triggered by fission events detected using BaF2 scintillators. A Monte Carlo code, inside the GEANT 3.21 framework with MICAP interface, has been used to identify the gamma and neutron contributions to the total number of collected RPC signals. A neutron sensitivity of (0.63±0.02)×10−3 (average energy 2 MeV) and a gamma sensitivity of (14.0±0.5)×10−3 (average energy 1.5 MeV) have been measured in double gap mode. Measurements done in single gap mode have shown that both neutron and gamma sensitivity are independent of the oiling treatment.

A long-term aging test of a Resistive Plate Chamber (RPC) was carried out with an intense gamma 137Cs source. The detector was operated in avalanche mode and had the bakelite surface treated with linseed oil. After the irradiation the estimated dose, charge and fluence were approximately equal to the expected values after 10 years of operation in the CMS barrel region. During and after the irradiation, the RPC performance was monitored with cosmic muons and showed no relevant aging effects. Moreover, no variation of the bakelite resistance was observed.

The formation of reactive compounds in the gas mixture during Resistive Plate Chambers (RPCs) operation at the CERN Gamma Irradiation Facility (GIF) is studied. Results from two different types of chambers are discussed: 50×50cm2 RPC prototypes and two final CMS-RB1 chambers. The RB1 detectors were also connected to a closed loop gas system. Gas composition and possible additional impurities have been monitored in different gamma irradiation conditions both in open and closed loop modes using a gas chromatograph. Dedicated measurements for fluoride concentration in the exhausted gas line were performed at different irradiations and operation conditions using a specific electrode and a High-Performance Liquid Chromatograph. The efficiency of the purifiers system present in the closed loop in removing the F- and others impurities has also been investigated. Finally, the chemical composition of the RPC electrode surface has been analyzed using an electron microscope equipped with an EDS/X-ray.

New results about the simulation of Resistive Plate Chambers are reported; particular enphasys is put in the understanding of charge spectra in regions where deviations from the pure avalanche mode of operation can be present.

Due to its large volume (18 m3)the Resistive Plate Chamber (RPC) detector of the Compact Muon Solenoid (CMS) experiment at the LHC proton collider (CERN, Switzerland) will employ a gas re-circulation system. Since the mixture composition and quality are crucial issues for the detector operation, CMS-RPC will use an online gas analysis and monitoring system. An overview of both the CMS-RPC gas system and gas monitoring system is given and the project parameters are described.

Resistive Plate Chambers have been chosen as dedicated trigger muon detector for the Compact Muon Solenoid experiment [1] at the Large Hadron Collider [2] at CERN. The system consists of about 3000 m2 of double gap RPC chambers placed in both the barrel and endcap muon regions.

Performances of the Gas Gain Monitoring system of the CMS RPC muon detectors after one year of operation at the scaled down closed loop recirculation gas system are presented. The GGM is made of 12 single-gap RPC's arranged in a cosmic ray telescope, with charge readout for online monitoring of working point. Preliminary results on sensitivity to gas changes and to environmental variables will be reported on.

Aims Statins are a widely recognized weapon in the primary and secondary prevention of coronary artery disease for their pleiotropic effects. However, recent reports from the cerebrovascular and pharmacological literature are insinuating concerns about a potential increase in the haemorrhagic risk among statin users. The effect of statins in postoperative bleeding should be carefully investigated in major cardiac surgery that exposes per se to risk of bleeding. Methods In this retrospective cohort study, we evaluated 441 patients who received atorvastatin until surgery and 213 patients who had never been treated with statins, undergoing elective primary isolated on-pump coronary artery bypass grafting. Postoperative bleedings, blood products use and complications were monitored during hospitalization. Results Preoperative and intraoperative variables were similar between groups. Early and overall postoperative bleedings were reduced among statin users, who had lower C-reactive protein values in the first postoperative day. Atorvastatin carries a strong protective effect against major bleedings, with a propensity score-adjusted odds ratio of 0.28 (P < 0.01). Also, blood products use for statin-treated patients was lower compared with controls, with fewer transfused patients and fewer red-packed cells units per transfused patient. Conclusion Preoperative atorvastatin use is associated with reduced risk of bleeding and blood products use after coronary artery bypass grafting, likely due to a reduction in the postoperative inflammatory response. Statin continuation at the highest tolerable dose should be encouraged before cardiac surgery. The preoperative use of statins in cardiac surgery as ‘bleeding-preventers’ might have profound clinical implications.

The Resistive Plate Chambers (RPCs) are employed in the CMS experiment at the LHC as dedicated trigger system both in the barrel and in the endcap. This note presents results of the RPC detector uniformity and stability during the 2011 data taking period, and preliminary results obtained with 2012 data. The detector uniformity has been ensured with a dedicated High Voltage scan with LHC collisions, in order to determine the optimal operating working voltage of each individual RPC chamber installed in CMS. Emphasis is given on the procedures and results of the High Voltage calibration. Moreover, an increased detector stability has been obtained by automatically taking into account temperature and atmospheric pressure variations in the CMS cavern.

Resistive Plate Chambers were tested in a muon and pion beam to study the performances at different running conditions. Results on a first chamber built without the linseed oil treatment of the bakelite surfaces are presented together with an evaluation of the local effects due to the spacers. These results are extrapolated to the conditions expected at LHC.

During the summer 2006, a first integrated test of a part of the CMS experiment was performed at CERN collecting a data sample of several millions of cosmic rays events. A fraction of the Resistive Plate Chambers system was successfully operated. Results on the RPC performance are reported.

Results from the gas gain monitoring (GGM) system for the RPC muon detector in the CMS experiment at the LHC are presented. The system is designed to provide fast and accurate determination of any shift in the working point of the chambers due to gas mixture changes.

The CMS muon system includes in both the barrel and endcap region Resistive Plate Chambers (RPC). They mainly serve as trigger detectors and also improve the reconstruction of muon parameters. Over the years, the instantaneous luminosity of the Large Hadron Collider gradually increases. During the LHC Phase 1 (~first 10 years of operation) an ultimate luminosity is expected above its design value of 10^34/cm^2/s at 14 TeV. To prepare the machine and also the experiments for this, two long shutdown periods are scheduled for 2013-2014 and 2018-2019. The CMS Collaboration is planning several detector upgrades during these long shutdowns. In particular, the muon detection system should be able to maintain a low-pT threshold for an efficient Level-1 Muon Trigger at high particle rates. One of the measures to ensure this, is to extend the present RPC system with the addition of a 4th layer in both endcap regions. During the first long shutdown, these two new stations will be equipped in the region |eta|<1.6 with 144 High Pressure Laminate (HPL) double-gap RPCs operating in avalanche mode, with a similar design as the existing CMS endcap chambers. Here, we present the upgrade plans for the CMS RPC system for the fist long shutdown, including trigger simulation studies for the extended system, and details on the new HPL production, the chamber assembly and the quality control procedures.

Resistive Plate Counters (RPC) detectors at the Large Hadron Collider (LHC) experiments use gas recirculation systems to cope with large gas mixture volumes and costs. In this paper a long-term systematic study about gas purifiers, gas contaminants and detector performance is discussed. The study aims at measuring the lifetime of purifiers with new and used cartridge material along with contaminants release in the gas system. During the data-taking the response of several RPC double-gap detectors was monitored in order to characterize the correlation between dark currents, filter status and gas contaminants.

Abstract A new generation of resistive plate chambers, capable of withstanding high particle fluxes (up to 2000 Hz · cm -2 ) and instrumented with precise timing readout electronics is proposed to equip two of the four high pseudorapidity stations of the CMS muon system. Double-gap RPC detectors, with each gap made of two 1.4 mm High Pressure Laminate electrodes and separated by a gas gap of the same thickness, are proposed. The new layout reduces the amount of the avalanche charge produced by the passage of a charged particle through the detector. This improves the RPC rate capability by reducing the needed time to collect this charge. To keep the RPC efficiency high, a sensitive, low-noise and high time resolution front-end electronics is needed to cope with the lower charge signal of the new RPC. An ASIC called PETIROC that has all these characteristics has been selected to read out the strips of new chambers. Thin (0.6 mm) printed circuit board, 160 cm long, equipped with pickup strips of 0.75 cm average pitch, will be inserted between the two new RPC's gaps. The strips will be read out from both ends, and the arrival time difference of the two ends will be used to determine the hit position along the strip. Results from the improved RPC equipped with the new readout system and exposed to cosmic muons in the high irradiation environment at CERN GIF++ facility are presented in this work.

The Resistive Plate Chambers (RPCs) sensitivity to neutrons has been simulated using GEANT code with MICAP and FLUKA interfaces. The calculations have been performed as a function of the neutrons energy in the range 0.02 eV–1 GeV. To evaluate the response of the detector in the LHC background environment, the neutron energy spectrum expected in the CMS muon barrel has been taken into account; a hit rate due to neutrons of about 0.6 Hz cm−2 has been estimated for a 250×250cm2 RPC in the RB1 station.

A method to simulate the Resistive Plate Chambers (RPCs) γ sensitivity has been developed using a Monte Carlo code. The sensitivity has been evaluated as a function of the γ energy in the range 0.1–100 MeV and for different spectra. To evaluate the response of the detector in a Large Hadron Collider (LHC) background environment the γ energy spectrum expected in the CMS muon barrel has been taken into account and the RPC γ sensitivity evaluated as a function of the detector size.

The CMS detector at the LHC has a redundant muon system.Two independent muon systems are used in the L1 trigger.One of them is based on wire chambers, the other on RPC detectors.Properly combining the answers of the two systems results in a highly efficient L1 trigger with high flexibility from the point of view of rate control.Simulation results show, however, that the RPC system suffers from false triggers caused by coincidence of spurious hits.System improvements, which could avoid oiling the chambers, are possible.RPCs have also proved to be very useful for muon track reconstruction.

During 2013 and 2014 (Long Shutdown LS1) the CMS experiment is upgrading the forward region installing a fourth layer of RPC detectors in order to complete and improve the muon system performances in the view of the foreseen high luminosity run of LHC. The new two endcap disks consists of 144 double-gap RPC chambers assembled at three different production sites: CERN, Ghent (Belgium) and BARC (India). The chamber components as well as the final detectors are subjected to full series of tests established in parallel at all the production sites.

The Resistive Plate Chambers (RPCs) are employed in the CMS Experiment at the LHC as dedicated trigger system both in the barrel and in the endcap. This article presents results of the radiation background measurements performed with the 2011 and 2012 proton-proton collision data collected by CMS. Emphasis is given to the measurements of the background distribution inside the RPCs. The expected background rates during the future running of the LHC are estimated both from extrapolated measurements and from simulation.

During Phase-2 of the LHC, known as the High Luminosity LHC (HL-LHC), the accelerator will increase its instantaneous luminosity to 5 × 1034 cm−2 s−1, delivering an integrated luminosity of 3000 fb−1 over 10 years of operation starting from 2027. In view of the HL-LHC, the CMS muon system will be upgraded to sustain efficient muon triggering and reconstruction performance. Resistive Plate Chambers (RPCs) serve as dedicated detectors for muon triggering due to their excellent timing resolution, and will extend the acceptance up to pseudorapidity values of |η|=2.4. Before Long Shutdown 3 (LS3), the RE3/1 and RE4/1 stations of the endcap will be equipped with new improved Resistive Plate Chambers (iRPCs) having different design and geometry than the present RPC system. The iRPC geometry configuration improves the detector's rate capability and its ability to survive the harsh background conditions of the HL-LHC . Also, new electronics with excellent timing performances (time resolution of less than 150 ps) are developed to read out the RPC detectors from both sides of the strips to allow for good spatial resolution along them. The performance of the iRPC has been studied with gamma radiation at the Gamma Irradiation Facility (GIF++) at CERN. Ongoing longevity studies will help to certify the iRPCs for the HL-LHC running period. The main detector parameters such as the current, rate and resistivity are regularly monitored as a function of the integrated charge. Preliminary results of the detector performance will be presented.

The Gas Gain Monitoring (GGM) system of the Resistive Plate Chamber (RPC) muon detector in the Compact Muon Solenoid (CMS) experiment provides fast and accurate determination of the stability in the working point conditions due to gas mixture changes in the closed loop recirculation system. In 2011 the GGM began to operate using a feedback algorithm to control the applied voltage, in order to keep the GGM response insensitive to environmental temperature and atmospheric pressure variations. Recent results are presented on the feedback method used and on alternative algorithms.

The performance at low pressure of 2 mm gap bakelite Resistive Plate Chambers, operated in streamer mode with a gas mixture of 58% Ar, 40% n-butane and 2% CF3Br, have been studied. Efficiency, time resolution and strip multiplicity appear satisfactory up to pressures of about 600 mbar, corresponding to altitudes around 4000m a.s.l.

A 3 mm wide-gap Resistive Plate Chamber, as proposed for CMS, has been tested in the H2 Cern beam line. Results on efficiency, rate capability, time resolution and cluster size are reported.

In this paper a model simulating the main aspects of avalanche growth and signal development in Resistive Plate Chambers (RPCs) is presented. The model has been used to compute the performances, in particular, charge distribution and efficiency of single- double- and multi-gap RPCs, and to compare them with the available experimental results. This model could be used to optimize the characteristics of this type of detector with a view to its use in the future large experiments at LHC: ATLAS and CMS.

The HL-LHC phase is designed to increase by an order of magnitude the amount of data to be collected by the LHC experiments. To achieve this goal in a reasonable time scale the instantaneous luminosity would also increase by an order of magnitude up to 6 · 1034 cm−2s−1. The region of the forward muon spectrometer (|η| > 1.6) is not equipped with RPC stations. The increase of the expected particles flux up to 2 kHz/cm2 (including a safety factor 3) motivates the installation of RPC chambers to guarantee redundancy with the CSC chambers already present. The current CMS RPC technology cannot sustain the expected background level. The new technology that will be chosen should have a high rate capability and provide a good spatial and timing resolution. A new generation of Glass-RPC (GRPC) using low-resistivity glass is proposed to equip at least the two most far away of the four high η muon stations of CMS. First the design of small size prototypes and studies of their performance in high-rate particles flux are presented. Then the proposed designs for large size chambers and their fast-timing electronic readout are examined and preliminary results are provided.

We report on a systematic study of double-gap and four-gap phenolic resistive plate chambers (RPCs) for the Phase-2 upgrade of the CMS muon system at high η. In the present study, we constructed real-sized double-gap and four-gap RPCs with gap thicknesses of 1.6 and 0.8 mm, respectively, with 2-mm-thick phenolic high-pressure-laminated (HPL) plates. We examined the prototype RPCs with cosmic rays and with 100-GeV muons provided by the SPS H4 beam line at CERN. To examine the rate capability of the prototype RPCs both at Korea University and at the CERN GIF++ facility, the chambers were irradiated with 137Cs sources providing maximum gamma rates of about 1.5 kHz cm−2. For the 1.6-mm-thick double-gap RPCs, we found the relatively high threshold on the produced detector charge was conducive to effectively suppressing the rapid increase of strip cluster sizes of muon hits with high voltage, especially when measuring the narrow-pitch strips. The gamma-induced currents drawn in the four-gap RPC were about one-fourth of those drawn in the double-gap RPC. The rate capabilities of both RPC types, proven through the present testing using gamma-ray sources, far exceeded the maximum rate expected in the new high-η endcap RPCs planned for future phase-II runs of the Large Hadron Collider (LHC).

Minimization of bleeding to reduce the use of blood products is of utmost importance in cardiac surgery. Statins are known for their pleiotropic effects beyond lipid-lowering properties, and the use of atorvastatin preoperatively is associated with reduced risk of bleeding and blood product use after coronary surgery. However, no studies have investigated if this beneficial effect also extends to aortic valve surgery. In this retrospective cohort study, 1145 consecutive patients undergoing elective primary isolated aortic valve replacement meeting the inclusion and exclusion criteria were selected from January 2009 to December 2017 (547 in the atorvastatin group, 598 in the control group). Postoperative bleeding, blood product use, and complications were monitored during hospitalization. Postoperative bleeding was significantly lower in the atorvastatin group compared with the controls in the first 12 h after surgery (372 ± 137 vs 561 ± 219 ml; P = 0.001) and considering overall bleeding (678 ± 387 vs 981 ± 345 ml, P = 0.001). A total of 32.3% of controls and 26.3% of atorvastatin users received packed red blood cells (P = 0.027), and major surgical complications were similar between the groups. Postoperative length of stay was shorter in the atorvastatin group with an average reduction of 1 day of hospitalization (6.0 ± 1.4 vs 6.9 ± 2.1 days; P = 0.001). Postoperative bleeding among the atorvastatin-treated patients was significantly greater in those taking lower doses compared to those taking higher doses of atorvastatin with a 20% between-group difference (P = 0.001). Preoperative treatment with atorvastatin might reduce postoperative bleeding and transfusion of packed red blood cells in patients undergoing elective isolated aortic valve replacement. This result might translate into faster recovery after surgery and reduced hospitalization costs.

RPC neutron sensitivity has been studied during two tests done with different neutrons energies. In the first test, neutrons from spontaneous fission events of 252Cf were used (average energy 2MeV); while in the second test neutrons were produced using a 50MeV deuteron beam on a 1cm thick beryllium target (average energy 20MeV). Preliminary results show that the neutron sensitivity in double gap mode is (0.52±0.03)×10−3 at about 2MeV and (5.3±0.5)×10−3 at about 20MeV.

The CMS experiment at the CERN Large Hadron Collider (LHC) is equipped with a redundant muon trigger system based on drift tubes chambers (DT) and cathode strip chamber (CSC), for the precise position measurement, and resistive plate chambers (RPC), for the bunch crossing identification and a preliminary fast measurement of the muon transverse momentum. The CMS RPC system is constituted by 480 chambers in the barrel and 756 chambers in the forward corresponding to a total surface of about 3500 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The design and construction has involved many laboratories scattered all over the word. An accurate quality control procedure has been established at different levels of the production to achieve final detectors with operation parameters well inside the CMS specifications. In the summer 2006 a preliminary slice test involving a fraction of the CMS detector was performed. The performance of the RPC system with cosmic rays was studied versus the magnetic field using final running hardware and software protocols. Results on the RPC main working parameters are reported.

New radioimaging techniques, exploiting the quantitative variables of imaging, permit to identify an hypothetical pathological tissue. We have applied this potential in a series of 72 adrenal incidentalomas (AIs) followed at our center, subdivided in functioning and non-functioning using laboratory findings. Each AI was studied in the preliminary non-contrast phase with a specific software (Mazda), surrounding a region of interest within each lesion. A total of 314 features were extrapolated. Mean and standard deviations of features were obtained and the difference in means between the two groups was statistically analyzed. Receiver Operating Characteristic (ROC) curves were used to identify an optimal cutoff for each variable and a prediction model was constructed via multivariate logistic regression with backward and stepwise selection. A 11-variable prediction model was constructed, and a ROC curve was used to differentiate patients with high probability of functioning AI. Using a threshold value of >-275.147, we obtained a sensitivity of 93.75% and a specificity of 100% in diagnosing functioning AI. On the basis of these results, computed tomography (CT) texture analysis appears a promising tool in the diagnostic definition of AIs.

The first CMS MB2 station, with one RPC and one DT module, has been tested with a muon beam under a high intensity photon flux at the CERN Gamma Irradiation Facility during the Autumn 2001 test. Results on efficiency, rate capability, cluster size and spatial resolution, for the RPC detector, are reported here. Studies with a small percentage of SF6 in the gas mixture, in order to decrease the noise rate, have also been carried out.

CMS experiment will use resistive plate chambers (RPCs) as dedicated muon trigger detectors. This requires good chamber global and local performance. To verify the chamber performance intensive tests are going on using a telescope installed at Bari Physics Department. The chamber efficiency is obtained by track reconstruction, which offers also the possibility to perform local efficiency studies. A brief description of the test set-up, reconstruction algorithm and test results are presented in this paper.

The CMS muon system is conceived for trigger and muon track reconstruction. The redundancy and robustness of the system are guaranteed by three complementary subsystems: drift tube in the barrel, cathode strip chamber in the end-cap and resistive plate chamber in barrel and end-cap. The installation of muon stations and read-out trigger electronic has been completed in middle 2007. Since than, a remarkable effort has been addressed to the detector commissioning in order to ensure the readiness of the hardware/software chain for the LHC start up operation. At the end of 2007, a test of an entire CMS slice has been performed, involving about 5% of muon stations. Several thousand cosmic muons events have been collected. Performance of the barrel chambers are reported.

In the CERN CMS experiment at LHC Collider special trigger signals called Technical Triggers will be used for the purpose of test and calibration. The Resistive Plate Chambers (RPC) based Technical Trigger system is a part of the CMS muon trigger system and is designed to detect cosmic muon tracks. It is based on two boards, namely RBC (RPC Balcony Collector) and TTU (Technical Trigger Unit). The proposed tracking algorithm (TA) written in VHDL and implemented in the TTU board detects single or multiple cosmic muon tracks at every bunch crossing along with their track lengths and corresponding chamber coordinates. The TA implementation in VHDL and its preliminary simulation results are presented.

Gas Electron Multiplier (GEM) technology is being considered for the forward muon upgrade of the CMS experiment in Phase 2 of the CERN LHC. Its first implementation is planned for the GE1/1 system in the 1.5 <| η |< 2.2 region of the muon endcap mainly to control muon level-1 trigger rates after the second long LHC shutdown. A GE1/1 triple-GEM detector is read out by 3,072 radial strips with 455 µrad pitch arranged in eight η-sectors. We assembled a full-size GE1/1 prototype of 1m length at Florida Tech and tested it in 20–120 GeV hadron beams at Fermilab using Ar/CO2 70∶30 and the RD51 scalable readout system. Four small GEM detectors with 2-D readout and an average measured azimuthal resolution of 36 µrad provided precise reference tracks. Construction of this largest GEM detector built to-date is described. Strip cluster parameters, detection efficiency, and spatial resolution are studied with position and high voltage scans. The plateau detection efficiency is [97.1 ± 0.2 (stat)]%. The azimuthal resolution is found to be [123.5 ± 1.6 (stat)] µrad when operating in the center of the efficiency plateau and using full pulse height information. The resolution can be slightly improved by ∼ 10 µrad when correcting for the bias due to discrete readout strips. The CMS upgrade design calls for readout electronics with binary hit output. When strip clusters are formed correspondingly without charge-weighting and with fixed hit thresholds, a position resolution of [136.8 ± 2.5 stat] µrad is measured, consistent with the expected resolution of strip-pitch/equation µrad. Other η-sectors of the detector show similar response and performance.

The CMS experiment will install a RE4 layer of 144 new Resistive Plate Chambers (RPCs) on the existing york YE3 at both endcap regions to trigger high momentum muons from the proton-proton interaction. In this paper, we present the detailed procedures used in the production of new RPC gas gaps adopted in the CMS upgrade. Quality assurance is enforced as ways to maintain the same quality of RPC gas gaps as the existing 432 endcap RPC chambers that have been operational since the beginning of the LHC operation.

In this paper, we report a systematic study of multigap Resistive Plate Chambers (RPCs) for high-η triggers in CMS. Prototype RPC modules with four- and six-gap structures have been constructed with phenolic high-pressure-laminated (HPL) plates and tested with cosmic muons and gamma rays irradiated from a 200-mCi 137Cs source. The detector characteristics of the prototype multigap RPCs were compared with those of the double-gap RPCs currently used in the CMS experiment at LHC. The mean values for detector charges of cosmic-muon signals drawn in the four- and six-gap RPCs for the efficiency values in the middle of the plateau were about 1.5 and 0.9 pC, respectively, when digitized with charge thresholds of 150 and 100 fC, respectively. They were respectively about one third and one fifth of that drawn in the current CMS double-gap RPC with a charge threshold of 200 fC. We concluded from the current R&D that use of the current phenolic-HPL multigap RPCs is advantageous to the high-η triggers in CMS in virtue of the smaller detector pulses.

A detailed study of the performance of resistive plate chambers, operated in streamer mode and filled with ozone safe gas mixtures, is reported; efficiency, time resolution, strip multiplicity, etc., have been measured both at atmospheric and at low pressure, to simulate a possible use of these detectors at high altitude.

A full-size prototype of the second barrel RPC station (RB2) for the CMS detector has been tested under high-irradiation flux at the CERN Gamma Irradiation Facility (GIF) during the 1999 beam test. The main requirements of RPCs as trigger detector have been studied: cluster size, time resolution, efficiency and rate capability. The timing features of a new front-end electronics were also investigated. Only the results obtained with the detector working in single-gap mode are reported here.

Results from aging tests on the bakelite used for the CMS RPCs are presented.Samples of melaminic bakelite were exposed to a heavy gamma and neutron radiation.Data on the bulk resistivity were collected while accumulating gamma and neutron doses and particles #uence up to values well beyond those expected in 10 years of RPCs operation in the barrel region of CMS.The test with gamma radiation was performed at the CERN Gamma Irradiation Facility (GIF) with a 20 Ci Cs source.A total absorbed dose of 5 Gy was accumulated during an irradiation period of about one month.The test with both neutron and gamma radiation was held at the Triga Mark II 250 kW reactor located in Pavia.A total of 80 h of exposure were accumulated integrating a neutron and gamma dose of about 80 Gy and a fast neutron #uence of some 10 cm\.Experimental data on dose rate in both the test facilities have been compared to simulation output and show a good agreement.

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 108ncm−2s−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.

The Resistive Plate Chambers (RPC) detector of the CMS experiment at the LHC proton collider (CERN, Switzerland) will employ an online gas analysis and monitoring system of the freon-based gas mixture used. We give an overview of the CMS RPC gas system, describe the project parameters and first results on gas-chromatograph analysis. Finally, we report on preliminary results for a set of monitor RPC.

Resistive Plate Chambers (RPC) have been chosen as dedicated trigger muon detectors for the Compact Muon Solenoid [CMS collaboration, Technical Design Report, CERN/LHCC 94-38, 1994. [1]] experiment at the Large Hadron Collider [The LHC project at CERN, LHC-project-report-36, 1996. [2]] at CERN. Four Italian groups from Bari, Frascati, Napoli and Pavia and two Bulgarian groups from Sofia have participated in designing and constructing the RPC barrel system. A sophisticated and complex production line has been organized by the collaboration to build the 480 RPC chambers, with a quality assurance (QA) test, made by 3 consecutive steps, in order to assure full functionality of the chambers. A final certification of the chambers has been made at ISR (CERN) with a month-long test. After that the RPCs have been coupled to the Drift Tube chamber and installed in the iron return yoke of the CMS solenoid. The first chamber was produced in 2002 and last was installed in October 2007. The system is now completely installed and commissioning has been going on since the second half of 2005 to complete the Large Hadron Collider (LHC) startup in the summer of 2008. The chamber construction, the test made, the main results achieved and a short description of all the services needed to run the RPC barrel system will be described in this paper.

With the increase of the LHC luminosity foreseen in the coming years, many detectors currently used in the different LHC experiments will be dramatically impacted and some need to be replaced or upgraded. The new ones should be capable to provide time information to reduce the data ambiguity due to the expected high pileup. We propose to equip CMS high |η| muon chambers with pairs of single gap RPC detectors read out by long pickup strips PCB. The precise time measurement (0<15 ps) of the signal induced by particles crossing the detector on both ends of each strip will give an accurate measurement of the position of the incoming particle along the strip. The absolute time measurement, determined by RPC signal (around 1.5 ns) will also reduce the data ambiguity due to the highly expected pileup and help to identify Heavy Stable Charged Particles (HSCP). The development of a specific electronic chain (analog front-end ASIC, time-to-digital converter stage and printed circuit board design) and the corresponding first results on prototype chambers are presented.

The CMS experiment recorded 177.75 /fb of proton-proton collision data during the RUN-1 and RUN-2 data taking period. Successful data taking at increasing instantaneous luminosities with the evolving detector configuration was a big achievement of the collaboration. The CMS RPC system provided redundant information for the robust muon triggering, reconstruction, and identification. To ensure stable data taking, the CMS RPC collaboration has performed detector operation, calibration, and performance studies. Various software and related tools are developed and maintained accordingly. In this paper, the overall performance of the CMS RPC system and experiences of the data taking during the RUN-2 period are summarised.

Two large double-gap resistive plate chambers, with 2 and 3 mm gap widths, were tested to study their response uniformity when operated in avalanche mode. The effects of mechanical tolerances and the presence of the spacers is thoroughly examined. Results on efficiency and time resolution are presented. We find that average performance and response uniformity over the whole chamber surface are fully adequate to the requirements of future collider experiments.

The muon spectrometer of the CMS (Compact Muon Solenoid) experiment at the Large Hadron Collider (LHC) is equipped with a redundant system made of Resistive Plate Chambers and Drift Tube in barrel and RPC and Cathode Strip Chamber in endcap region. In this paper, the operations and performance of the RPC system during the first three years of LHC activity will be reported. The stability of RPC performance, such as efficiency, cluster size and noise, will be reported. Finally, the radiation background levels on the RPC system have been measured as a function of the LHC luminosity. Extrapolations to the LHC and High Luminosity LHC conditions are also discussed.

During Run2 the high instantaneous luminosity, up to 2.21034cm−2s−1, lead to a substantial hit rate in the Compact Muon Solenoid experiment’s muon chambers due to multiple background sources to physics processes sought for at LHC. In this article we will describe the analysis method devised to measure and identify the contributions to such background in the Resistive Plate Chambers. Thorough understanding of the background rates provides the base for the upgrade of the muon detectors for the High-Luminosity LHC.

Adopting and maintaining a physically active lifestyle provides si¬gnificant health benefits to people with diabetes and prediabetes by increasing energy expenditure, insulin sensitivity, and physical fitness and decreasing chronic low-grade inflammation. Physical activity (PA)/exercise favors control of hyperglycemia and other risk factors for cardiovascular disease (CVD) and, therefore, it is recommended for diabetes prevention and treatment and for improving overall health. According to current guidelines, people with type 2 diabetes are re-commended to perform at least 150 min/week of moderate-to-vigorous intensity aerobic exercise plus 2-3 sessions/week of resistance exercise on non-consecutive days. Unfortunately, these individuals are usually well below the recommended level of PA and, hence, it is difficult for them to put into action guideline recommendations for a number of external and internal barriers, thus suggesting the need for effective strategies to promote a sustained behavior change. Several randomi¬zed clinical trials have shown that supervised exercise programs are effective in improving surrogate endpoints such as blood glucose and other CVD risk factors, physical fitness, and well-being. However, such programs are not suitable for long-term implementation in rou¬tine clinical practice and adherence to PA/exercise is usually strictly dependent on participation to supervised sessions and falls once the intervention ends. In this regard, counseling interventions appear to be more feasible and adequate to promote a true, long-lasting beha¬vior change. A limited number of studies have tested the efficacy of counseling interventions designed to promote walking through the provision of pedometers. These interventions resulted in modest and transient increases in moderate-to-vigorous PA (MVPA) and, accor¬dingly, failed to significantly improve CVD risk factors and other sur¬rogate outcomes or to produce sustained increases in cardiorespiratory fitness. These results are in contrast with those of several epidemio¬logical surveys, showing that, in physically inactive and sedentary or unfit individuals, even modest amounts of (MV)PA, corresponding to one-third to one-half of those recommended by guidelines, exert a beneficial impact on morbidity and mortality. This discrepancy might be explained by the fact that walking-based interventions are focused only on leisure-time MPVA. Conversely, current guidelines consider also other domains, such as sedentary behavior and light-intensity PA (LPA), and other settings, such as home, work and commuting, as they recommend also to decrease the amount of sedentary (SED)-time and to interrupt prolonged sitting with bouts of LPA every 30 min. In fact, in the Italian Diabetes and Exercise Study 2 (IDES_2), a counse¬ling intervention targeting both MVPA and sedentary behavior was effective in promoting increases in MVPA, which were modest but sustained over a three-year follow-up and associated with larger de¬creases in SED-time and corresponding increases in LPA. This resulted in clinically meaningful improvements in physical fitness and, to a les¬ser extent, in CVD risk factors and scores over a three-year follow-up. Conversely, no clinically meaningful effects were observed in counse¬ling intervention targeting only SED-time. In conclusion, counseling interventions are effective in producing clinically meaningful effects, even when resulting in only modest increments in leisure-time MVPA, provided that they also target the other domains and settings of PA/sedentary behavior.

Resistive Plate Chambers (RPCs) are gaseous detectors with high performance, robustness, and construction simplicity used for many years in HEP experiments. In this work, prototypes with 1.0 mm gas gap thickness and 1.43 mm HPL electrode thickness, are characterized. The prototypes were tested under a muon beam and different intensities of gamma background radiation at GIF++ to measure the muon efficiency, muon cluster size, and time resolution among other performance features related to the 1.0 mm-gap thickness. As well, the last section reports the results of the detector response using eco-friendly gas mixtures based on HFO (R1234-ze) and CO2.

Boron Neutron Capture Therapy (BNCT) is an innovative and highly selective treatment against cancer. Nowadays, in vivo boron dosimetry is an important method to carry out such therapy in clinical environments. In this work, different imaging methods were tested for dosimetry and tumor monitoring in BNCT based on a Compton camera detector. A dedicated dataset was generated through Monte Carlo tools to study the imaging capabilities. We first applied the Maximum Likelihood Expectation Maximization (MLEM) iterative method to study dosimetry tomography. As well, two methods based on morphological filtering and deep learning techniques with Convolutional Neural Networks (CNN), respectively, were studied for tumor monitoring. Furthermore, clinical aspects such as the dependence on the boron concentration ratio in image reconstruction and the stretching effect along the detector position axis were analyzed. A simulated spherical gamma source was studied in several conditions (different detector distances and boron concentration ratios) using MLEM. This approach proved the possibility of monitoring the boron dose. Tumor monitoring using the CNN method shows promising results that could be enhanced by increasing the training dataset.

The performance of the Resistive Plate Chambers-based muon trigger of the CMS detector has been studied by means of a full simulation of the system under realistic operating conditions. Requirements on the performance of the chambers are deduced.

The Resistive Plate Chambers [M. Abbrescia, et al., Nucl. Instr. and Meth. A 550 (2005) 116] are used in the CMS experiment [CMS Collaboration, The CMS experiment at the CERN LHC 2008, J. Inst. 3 (2008) S08004] as a dedicated muon trigger both in barrel and endcap system. About 4000m2 of double gap RPCs have been produced and have been installed in the experiment since more than one and half Years. The full barrel system and a fraction of the endcaps have been monitored to study dark current behaviour and system stability, and have been extensively commissioned with Cosmic Rays collected by the full CMS experiment.

An RPC based system will be employed for the CMS muon first level trigger. Severe quality controls and certification have been established all along the entire production chain. Procedures are briefly described and results for the acceptance percentage are given for the second part of the single gaps and double gaps production. Summary results are also reported for the full sets of tested chambers.

Abstract The expected radiation background in the CMS RPC system has been studied using the MC prediction with the CMS FLUKA simulation of the detector and the cavern. The MC geometry used in the analysis describes very accurately the present RPC system but still does not include the complete description of the RPC upgrade region with pseudorapidity 1.9 &lt; |η| &lt; 2.4. Present results will be updated with the final geometry description, once it is available. The radiation background has been studied in terms of expected particle rates, absorbed dose and fluence. Two High Luminosity LHC (HL-LHC) scenarios have been investigated — after collecting 3000 and 4000 fb -1 . Estimations with safety factor of 3 have been considered, as well.

The CMS experiment implements a two-level triggering system composed of Level-1, instrumented by custom-design hardware boards, and a software High Level Trigger. To cope with the more challenging luminosity conditions, a new Level-1 architecture has been deployed during run II. This new architecture exploits in a better way the redundancy and complementarity of the three muon subsystems: Cathode Strip Chambers (CSC), Drift Tubes (DT) and Resistive Plate Chambers (RPC). The role of each subsystem in the Level-1 Muon Trigger is described here, highlighting the contribution from the RPC system. Challenges brought by the HL-LHC environment and new possibilities coming from detector and trigger upgrades are also discussed.

The high pseudorapidity ($\eta$) region of the Compact Muon Solenoid (CMS) muon system is covered by Cathode Strip Chambers only and lacks redundant coverage despite the fact that it is a challenging region for muons in terms of backgrounds and momentum resolution. During the annual Year-End Technical Stops 2022 & 2023, two new layers of improved Resistive Plate Chambers (iRPC) will be added, RE3/1 & RE4/1, which will completely cover the region of $1.8 < |\eta| < 2.4$ in the endcap. Thus, the additional new chambers will lead to increase efficiency for both trigger and offline reconstruction in the difficult region where the background is the highest and the magnetic field is the lowest within the muon system. The extended RPC system will improve the performance and the robustness of the muon trigger. The final design of iRPC chambers and the concept to integrate and install them in the CMS muon system have been finalized. In this report, the main results demonstrating the implementation and installation of the new iRPC detectors in the CMS muon system at high $|\eta|$ region will be presented.

Abstract The present RPC Link System has been servicing as one of the CMS subsystems since installation in 2008. Although the current Link System has been functioning well for the past 13 years, the aging of its electronic components and lack of radiation hard ASICs could present problems for future operations. Additionally, the needs to have a more robust control interface against electromagnetic interference, to improve the trigger performance with finer time granularity and to incorporate a higher bandwidth transmission lines led the idea of upgrading the Link System for the HL-LHC. This paper reviews the features of the recently developed prototype of the new Link System.

In this paper, we describe a dedicated test to study possible long-term aging effects on Resistive Plate Chambers (RPCs). A double gap detector was operated under gamma irradiation for a period approximately equal to 10 years of LHC in the CMS-barrel region: an integrated dose of about 1.6Gy and a total charge of about 0.05C/cm2 gap were accumulated on the chamber. The results show no relevant aging effect. Also the RPC sensitivity to 60Co gamma energies is measured.

Neutrons from a reactor and from a cyclotron have been used to characterise the CMS Resistive Plate Chambers (RPCs) front-end chip to neutron-induced damaging events. Single Event Upset (SEU) cross-sections have been measured up to 60MeV for different chip thresholds. Tests at a reactor were done with an integrated fast (En>3MeV) neutron fluence of 1.7×1010cm−2 and a thermal neutron fluence of 9.5×1011cm−2. High-energy neutrons from a cyclotron were used up to a fluence of 1012cm−2. Data indicate the existence of a chip SEU sensitivity already at thermal energy and a saturated SEU cross-section from 3 to 60MeV. Values of the SEU cross-sections from the thermal run well agree with those obtained by another CMS group that uses the same technology (0.8μm BiCMOS) though with different architecture. Cross-sections obtained with fast neutrons (from 3MeV to about 10MeV) are consistently higher by one order of magnitude compared to the thermal one. The average time between consecutive SEU events in each chip of the CMS barrel RPCs can be estimated to be 1h.

A new muon reconstruction algorithm is introduced at the CMS experiment. This algorithm reconstructs muons using only the central tracker and the Resistive Plate Chamber (RPC). The aim of this work is to study how a muon reconstructed only with tracker and RPC information would perform compared to the standard muon reconstruction of the CMS detector. The efficiencies to reconstruct and identify a RPC muon with a transverse momentum greater than 20 GeV/c are measured. The probabilities to misidentify hadrons as muons at low transverse momentum are also reported. These probabilities are compared to the standard muon identification used at CMS.

The Compact Muon Solenoid (CMS) experiment at the LHC is planning an upgrade of its muon detection system aiming to extend the muon detection capabilities in the forward region with the installation of new muon stations based on Gas Electron Multiplier (GEM) and Resistive Plate Chambers (RPC) technologies during the so-called Phase-2 upgrade scenario. With the imminent increase on luminosity to 5 × 1034cm-2s-1 and center of mass collision energy of 14 TeV an unprecedented and hostile radiation environment will be created, the most affected detectors will be the ones located in the forward region where the intense flux of neutrons and photons could potentially degrade the detector performance. Using FLUKA simulation the expected radiation environment is estimated for the regions of interest, possible shielding scenarios are proposed and the effect on the detector performance is discussed.

Gas Electron Multiplier (GEM) technology is being considered for the forward muon upgrade of the CMS experiment in Phase 2 of the CERN LHC. Its first implementation is planned for the GE1/1 system in the $1.5 < \mid\eta\mid < 2.2$ region of the muon endcap mainly to control muon level-1 trigger rates after the second long LHC shutdown. A GE1/1 triple-GEM detector is read out by 3,072 radial strips with 455 $\mu$rad pitch arranged in eight $\eta$-sectors. We assembled a full-size GE1/1 prototype of 1m length at Florida Tech and tested it in 20-120 GeV hadron beams at Fermilab using Ar/CO$_{2}$ 70:30 and the RD51 scalable readout system. Four small GEM detectors with 2-D readout and an average measured azimuthal resolution of 36 $\mu$rad provided precise reference tracks. Construction of this largest GEM detector built to-date is described. Strip cluster parameters, detection efficiency, and spatial resolution are studied with position and high voltage scans. The plateau detection efficiency is [97.1 $\pm$ 0.2 (stat)]\%. The azimuthal resolution is found to be [123.5 $\pm$ 1.6 (stat)] $\mu$rad when operating in the center of the efficiency plateau and using full pulse height information. The resolution can be slightly improved by $\sim$ 10 $\mu$rad when correcting for the bias due to discrete readout strips. The CMS upgrade design calls for readout electronics with binary hit output. When strip clusters are formed correspondingly without charge-weighting and with fixed hit thresholds, a position resolution of [136.8 $\pm$ 2.5 stat] $\mu$rad is measured, consistent with the expected resolution of strip-pitch/$\sqrt{12}$ = 131.3 $\mu$rad. Other $\eta$-sectors of the detector show similar response and performance.

Fifteen consecutive cases of ventricular septal defect (VSD) associated with aortic regurgitation (AR), observed from January 1972 to November 1980 in the Department of Cardiac Surgery of Massa Hospital were evaluated from a pathological and hemodynamic point of view and surgically treated. All patients underwent cardiac catheterization and selective aortography before and after surgical correction. The VSD was closed by Dacron patch in 10 cases and by direct suture in 5. Aortotomy was performed in 9 patients who presented moderate to severe AR; among these 7 underwent valvular repair and two prosthetic replacement. One patient died (6.6% mortality) 8 days after the operation; another developed complete atrioventricular block requiring insertion of epicardial pace-maker. Residual AR has been found in only one of the 6 patients with preoperative mild degree of AR in whom only the closure of the VSD was carried out. Residual AR is also present in 4 patients who required valvular repair, but only in one it is severe. We favor correction at preschool age on the principle that early closure of the VSD may control or prevent the progression of AR. However, in small children in whom the severity of AR may suggest the necessity of valve replacement, the operation is postponed as long as possible to avoid functional prosthetic stenosis later in life.

In this paper some results obtained by the CMS Resistive Plate Chamber collaboration during its five years long period of research and development are reported. The importance of the simulation in the design of the Resistive Plate Chambers for CMS is stressed.

A double gap Bakelite Resistive Plate Chamber (RPC) with common readout has been exposed to the radiation emitted from a 252 Cf source to measure its neutron and γ sensitivity.RPC signals were triggered by fission events detected using BaF 2 scintillators.A GEANT 3.21 Monte Carlo code with MICAP interface estimated the γ and neutron contributions to the total number of collected RPC signals.A neutron sensitivity s n = 0.46 × 10 -3 at ≈ 2 MeV and a γ sensitivity s γ = 12.6 × 10 -3 at ≈ 1.5 MeV have been measured for the double gap configuration.* Speaker.

The design and test of a single-gap resistive plate chamber instrumented with mini-strip readout is discussed. Efficiency and charge distribution are studied by means of cosmic muons using a small vertical telescope. The feasibility of inferring the position of the impinging particle is studied from the peak charge strip position. On the basis of these results a dedicated front-end VLSI is designed and prototyped.

The CMS experiment has 1054 RPCs in its muon system. Monitoring their currents is the first essential step towards maintaining the stability of the CMS RPC detector performance. The current depends on several parameters such as applied voltage, luminosity, environmental conditions, etc. Knowing the influence of these parameters on the RPC current is essential for the correct interpretation of its instabilities as they can be caused either by changes in external conditions or by malfunctioning of the detector in the ideal case. We propose a Machine Learning(ML) based approach to be used for monitoring the CMS RPC currents. The approach is crucial for the development of an automated monitoring system capable of warning for possible hardware problems at a very early stage, which will contribute further to the stable operation of the CMS RPC detector.

The Muon Upgrade Phase II of the Compact Muon Solenoid (CMS) aims to guarantee the optimal conditions of the present system and extend the η coverage to ensure a reliable system for the High Luminosity Large Hadron Collider (HL-LHC) period. The Resistive Plate Chambers (RPCs) system will upgrade the off-detector electronics (called link system) of the chambers currently installed chambers and place improved RPCs (iRPCs) to cover the high pseudo−rapidity region, a challenging region for muon reconstruction in terms of background and momentum resolution. In order to find the best option for the iRPCs, an R&D program for new detectors was performed and real size prototypes have been tested in the Gamma Irradiation Facility (GIF++) at CERN. The results indicated that the technology suitable for the high background conditions is based on High Pressure Laminate (HPL) double-gap RPC. The RPC Upgrade Phase II program is planned to be ready after the Long Shutdown 3 (LS3).

Cancer Management and Research is an international, peer-reviewed open access journal focusing on cancer research and the optimal use of preventative and integrated treatment interventions to achieve improved outcomes, enhanced survival and quality of life for the cancer patient.

The Resistive Plate Chambers (RPC) detector of the CMS experiment at the LHC proton collider (CERN, Switzerland) will employ an online gas analysis and monitoring system of the freon-based gas mixture used. We give an overview of the CMS RPC gas system, describe the project parameters and first results on gas-chromatograph analysis. Finally, we report on preliminary results for a set of monitor RPC.

Abstract As part of the Compact Muon Solenoid experiment Phase-II upgrade program, new resistive plate chambers will be installed in the region at low angle with respect to the beam collision axis, in order to improve the detection of muons with a low transverse momentum. High background conditions are expected in this region during the high-luminosity phase of the Large Hadron Collider, therefore an improved-RPC design has been proposed with a new front-end electronics to sustain a higher particle rate capability and better time resolution. A new technology is used in the front-end electronics resulting in low achievable signal detection of 1–20 fC. Crucial in the design of the improved-RPC is the capability of a two-dimensional readout in order to improve the spatial resolution, mainly motivated by trigger requirements. In this work, the first performance results towards this two-dimensional readout are presented, based on data taken on a real-size prototype chamber with two embedded readout planes with orthogonal strips.

Resistive Plate Chambers have been chosen as dedicated trigger muon detectors for the Compact Muon Solenoid experiment at the Large Hadron Collider at CERN. The barrel RPC detector consists of 480 chambers of different forms and sizes, equipped with 75,000 strips and covering an area of about 2400 m2. About one-third of RPC barrel chambers have been produced up to the end of 2003 and these 150 chambers, produced and assembled in Italy, have been extensively tested at the two Italian test stands of Bari and Pavia by the RPC barrel collaboration. Preliminary results of the production and test of the chambers will be described here.

The Resistive Plate Chambers (RPC) are used in the CMS experiment at the trigger level and also in the standard offline muon reconstruction. In order to guarantee the quality of the data collected and to monitor online the detector performance, a set of tools has been developed in CMS which is heavily used in the RPC system. The Web-based monitoring (WBM) is a set of java servlets that allows users to check the performance of the hardware during data taking, providing distributions and history plots of all the parameters. The functionalities of the RPC WBM monitoring tools are presented along with studies of the detector performance as a function of growing luminosity and environmental conditions that are tracked over time.

February 1 th 2013 marked the end of the first period of running of the Large Hadron Collider (LHC) and the start of a two-year break from operation (LS1) aimed at consolidating both the accelerator as well as the detectors. By the end of LS1, the LHC is expected to provide collisions at 13 Tev. While, by 2020, the ultimate instantaneous luminosity is expected to be 1034/cm2/s. To prepare for this scenario, the Resistive Plate Chamber system at the CMS experiment is planning several detector maintainance and consolidation interventions. These include High Voltage and Low Voltage system reparations, gas leak identification and reparation, signal channel connectivity and functionality. Commissioning and upgrade plans for the existing CMS RPC system are presented here.

For the High-Luminosity LHC (HL-LHC) phase the CMS GEM Collaboration is planning to install new large-size (990×220–455mm2) triple-GEM detectors, equipped with a new readout system, in the forward region of the muon system (1.5< |η| <2.2) of the CMS detector. Combining triggering and tracking functionalities the new triple-foil Gas Electron Multiplier (GEM) chambers will improve both the performance of the CMS muon trigger and the muon reconstruction/identification in CMS experiment. The addition of triple-GEM chambers to the forward region of the CMS muon system will add a necessary layer of redundancy. Starting from 2009 the CMS GEM Collaboration has built several small and full-size prototypes with different geometries, keeping improving the assembly techniques. All these prototypes have been tested in laboratories as well as with beam tests at the CERN Super Proton Synchrotron (SPS) and at Fermi National Accelerator Laboratory. In this contribution we will report on the status of the CMS upgrade project with triple-GEM chambers and its impact on the CMS performance as well as the hardware architectures and expected capability of the CMS GEM readout system.

In view of the high-luminosity phase of the LHC, the CMS Collaboration is considering the use of Gas Electron Multiplier (GEM) detector technology for the upgrade of its muon system in the forward region. With their ability to handle the extreme particle rates expected in that area, such micro-pattern gas detectors can sustain a high performance and redundant muon trigger system. At the same time, with their excellent spatial resolution, they can improve the muon track reconstruction and identification capabilities of the forward detector, effectively combining tracking and triggering functions in one single device. The present status of the CMS GEM project will be reviewed, highlighting importants steps and achievements since the start of the R&D activities in 2009. The baseline design of the triple-GEM detectors proposed for installation in different stations of the CMS muon endcap system will be described, along with the associated frontend electronics and data-acquisition system. The expected impact on the performance of the CMS muon system will be discussed, and results from detector tests, both in the lab and in test beams will be presented.

In the framework of the High Luminosity LHC upgrade program, the CMS muon group built several different RPC prototypes that are now under test at the new CERN Gamma Irradiation Facility (GIF++). A dedicated Detector Control System (DCS) has been developed using the WinCC-OA tool to control and monitor these prototype detectors and to store the measured parameters data. Preliminary efficiency studies that set the base performance measurements of CMS RPC for starting aging studies are also presented.

We report on a systematic study of double-gap and four-gap phenolic resistive plate chambers (RPCs) for future high-η RPC triggers in the CMS. In the present study, we constructed real-sized double-gap and four-gap RPCs with gap thicknesses of 1.6 and 0.8 mm, respectively, with 2-mm-thick phenolic high-pressure-laminated (HPL) plates. We examined the prototype RPCs for cosmic rays and 100 GeV muons provided by the SPS H4 beam line at CERN. We applied maximum gamma rates of 1.5 kHz cm-2 provided by 137Cs sources at Korea University and the GIF++ irradiation facility installed at the SPS H4 beam line to examine the rate capabilities of the prototype RPCs. In contrast to the case of the four-gap RPCs, we found the relatively high threshold was conducive to effectively suppressing the rapid increase of strip cluster sizes of muon hits with high voltage, especially when measuring the narrow-pitch strips. The gamma-induced currents drawn in the four-gap RPC were about one-fourth of those drawn in the double-gap RPC. The rate capabilities of both RPC types, proven through the present testing using gamma-ray sources, far exceeded the maximum rate expected in the new high-η endcap RPCs planned for future phase-II LHC runs.

The muon spectrometer of the Compact Muon Solenoid (CMS) at the CERN Large Hadron Collider (LHC) is equipped with a redundant muon system based on Drift Tubes (DT) Chambers, Cathode Strip Chambers (CSC) and Resistive Plate Chambers (RPC) for muon identification, precise momentum measurement and triggering. On 30th March 2010, LHC started proton proton collisions at a center of mass energy of 7 TeV. The operations and performance of the DT and RPC systems during the first three years of LHC activity with increasing instantaneous luminosity will be reported. The DT local trigger performance is described, showing how the challenging design goals have been met. Special attention will be given to the RPC working point calibration procedure and to the efficiency stability of the RPC system, confirming the excellent behavior and the fulfillment of the CMS requirements. Finally the radiation background levels in the DT and RPC systems have been measured. Extrapolations to the LHC design conditions are also discussed.