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Mohit Gola

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DOI: 10.1016/j.nima.2022.166716
2022
Cited 10 times
Quality control of mass-produced GEM detectors for the CMS GE1/1 muon upgrade
The series of upgrades to the Large Hadron Collider, culminating in the High Luminosity Large Hadron Collider, will enable a significant expansion of the physics program of the CMS experiment. However, the accelerator upgrades will also make the experimental conditions more challenging, with implications for detector operations, triggering, and data analysis. The luminosity of the proton-proton collisions is expected to exceed $2-3\times10^{34}$~cm$^{-2}$s$^{-1}$ for Run 3 (starting in 2022), and it will be at least $5\times10^{34}$~cm$^{-2}$s$^{-1}$ when the High Luminosity Large Hadron Collider is completed for Run 4. These conditions will affect muon triggering, identification, and measurement, which are critical capabilities of the experiment. To address these challenges, additional muon detectors are being installed in the CMS endcaps, based on Gas Electron Multiplier technology. For this purpose, 161 large triple-Gas Electron Multiplier detectors have been constructed and tested. Installation of these devices began in 2019 with the GE1/1 station and will be followed by two additional stations, GE2/1 and ME0, to be installed in 2023 and 2026, respectively. The assembly and quality control of the GE1/1 detectors were distributed across several production sites around the world. We motivate and discuss the quality control procedures that were developed to standardize the performance of the detectors, and we present the final results of the production. Out of 161 detectors produced, 156 detectors passed all tests, and 144 detectors are now installed in the CMS experiment. The various visual inspections, gas tightness tests, intrinsic noise rate characterizations, and effective gas gain and response uniformity tests allowed the project to achieve this high success rate.
DOI: 10.1016/j.nima.2018.11.061
2019
Cited 16 times
Layout and assembly technique of the GEM chambers for the upgrade of the CMS first muon endcap station
Triple-GEM detector technology was recently selected by CMS for a part of the upgrade of its forward muon detector system as GEM detectors provide a stable operation in the high radiation environment expected during the future High-Luminosity phase of the Large Hadron Collider (HL-LHC). In a first step, GEM chambers (detectors) will be installed in the innermost muon endcap station in the $1.6<\left|\eta\right|<2.2$ pseudo-rapidity region, mainly to control level-1 muon trigger rates after the second LHC Long Shutdown. These new chambers will add redundancy to the muon system in the $\eta$-region where the background rates are high, and the bending of the muon trajectories due to the CMS magnetic field is small. A novel construction technique for such chambers has been developed in such a way where foils are mounted onto a single stack and then uniformly stretched mechanically, avoiding the use of spacers and glue inside the active gas volume. We describe the layout, the stretching mechanism and the overall assembly technique of such GEM chambers.
DOI: 10.1029/rs025i005p00883
1990
Cited 24 times
High‐latitude irregularity spectra deduced from scintillation measurements
High‐latitude scintillation data show that the strength and spectral index of intensity scintillation are dependent on the propagation geometry. It will be shown that anisotropic irregularity spectra, with different indices along and across the magnetic field, lead to geometrical effects similar to those observed. In general, the spectrum along the magnetic field is steeper than that across the field, and the difference is more pronounced for nighttime conditions. Spectral anisotropy can be interpreted as a size‐dependent irregularity anisotropy. Our data indicate that large‐scale irregularities in the daytime and nighttime ionosphere are almost isotropic, while small‐scale irregularities are anisotropic and considerably more so at night than during the day. It will be shown that anisotropic irregularity spectra could account for the observed scintillation and in situ temporal spectra with frequency‐dependent slope. The effect depends strongly on the geometry.
DOI: 10.1016/j.nima.2020.164104
2020
Cited 8 times
Performance of prototype GE1<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="d1e1083" altimg="si14.svg"><mml:mo>∕</mml:mo></mml:math>1 chambers for the CMS muon spectrometer upgrade
The high-luminosity phase of the Large Hadron Collider (HL-LHC) will result in ten times higher particle background than measured during the first phase of LHC operation. In order to fully exploit the highly-demanding operating conditions during HL-LHC, the Compact Muon Solenoid (CMS) Collaboration will use Gas Electron Multiplier (GEM) detector technology. The technology will be integrated into the innermost region of the forward muon spectrometer of CMS as an additional muon station called GE1∕1. The primary purpose of this auxiliary station is to help in muon reconstruction and to control level-1 muon trigger rates in the pseudo-rapidity region 1.6≤|η|≤2.2. The new station will contain trapezoidal-shaped GEM detectors called GE1∕1 chambers. The design of these chambers is finalized, and the installation is in progress during the Long Shutdown phase two (LS-2) that started in 2019. Several full-size prototypes were built and operated successfully in various test beams at CERN. We describe performance measurements such as gain, efficiency, and time resolution of these prototype chambers, developed after years of R&D, and summarize their behavior in different gas compositions as a function of the applied voltage.
DOI: 10.1016/j.nima.2019.162967
2020
Cited 7 times
Performance of the triple GEM detector built using commercially manufactured GEM foils in India
The Gas Electron Multiplier (GEM) detectors has been utilized for various applications due to their excellent spatial resolution, high rate capabilities and flexibility in design. The GEM detectors stand as a promising device to be used in nuclear and particle physics experiments. Many future experiments and upgrades are looking forward to use this technology leading to high demand of GEM foils. Until now, CERN is the only reliable manufacturer and distributor of GEM foils, but with technology transfer, few other industries across the globe have started manufacturing these foils employing the same photo-lithographic technique. The Micropack Pvt. Ltd. is one such industry in India which produced first few 10cm×10cm GEM foils, which were then distributed to few collaborating partners for testing reliability and performance of foils before they can be accepted by the scientific community. Characterization of three such foils have already been performed by studying their optical and electrical properties. Using these foils a triple GEM detector has been built and various performance characteristics have been measured. In this paper, we specifically report measurements on gain, resolution and response uniformity, by utilizing local quality control set-ups existing at University of Delhi.
DOI: 10.1016/0021-9169(92)90146-c
1992
Cited 16 times
Behaviour of HILAT scintillation over spitsbergen
Results of the amplitude scintillation morphology of the HILAT satellite 137 MHz beacon transmission as measured at the Polish Polar Station at Hornsund, Spitsbergen (Δ = 73.4°) are presented. Seasonal, diurnal and latitudinal dependencies of scintillation intensity on magnetic activity were analyzed from over 2250 satellite passes recorded at solar minimum between April 1985 and March 1986. Regions with strong scintillation intensity appear to follow the auroral oval expansion and to move sunward with increasing level of magnetic activity. Maximum amplitude scintillation region coincides with the dayside cusp/cleft position during high magnetic activity. The dawn-dusk asymmetry in scintillation intensity is more distinct in winter than other months. The estimated summer/winter ratio of scintillation intensity is 1.4: 1. Numerical simulations compared with the observational results indicate that high latitude irregularities < 1 km are field-aligned and rod-like rather than sheet-like.
DOI: 10.1016/j.nima.2018.02.078
2018
Cited 5 times
Development, characterization and qualification of first GEM foils produced in India
The increasing demand for Gas Electron Multiplier (GEM) foils has been driven by their application in many current and proposed high-energy physics experiments. Micropack, a Bengaluru-based company, has established and commercialized GEM foils for the first time in India. Micropack used the double-mask etching technique to successfully produce 10 cm × 10 cm GEM foil. In this paper, we report on the development as well as the geometrical and electrical properties of these foils, including the size uniformity of the holes and leakage current measurements. Our characterization studies show that the foils are of good quality and satisfy all the necessary quality control criteria.
DOI: 10.1088/1748-0221/15/05/p05023
2020
Cited 4 times
Detector Control System for the GE1/1 slice test
Gas Electron Multiplier (GEM) technology, in particular triple-GEM, was selected for the upgrade of the CMS endcap muon system following several years of intense effort on R&D. The triple-GEM chambers (GE1/1) are being installed at station 1 during the second long shutdown with the goal of reducing the Level-1 muon trigger rate and improving the tracking performance in the harsh radiation environment foreseen in the future LHC operation [1]. A first installation of a demonstrator system started at the beginning of 2017: 10 triple-GEM detectors were installed in the CMS muon system with the aim of gaining operational experience and demonstrating the integration of the GE1/1 system into the trigger. In this context, a dedicated Detector Control System (DCS) has been developed, to control and monitor the detectors installed and integrating them into the CMS operation. This paper presents the slice test DCS, describing in detail the different parts of the system and their implementation.
DOI: 10.1088/1748-0221/14/08/p08004
2019
Cited 4 times
Stability tests performed on the triple GEM detector built using commercially manufactured GEM foils in India
The Gas Electron Multiplier (GEM) technology is based on thin polymer foils cladded with copper on both the sides with a regular matrix of holes. Due to the limited manufacturing capacity of CERN, these GEM foils are now commercially manufactured also by Micropack Pvt. Ltd., a company based in India. In order to gain an insight on the behaviour of detectors built using the foils from Micropack, it is important to study various long and short term effects on these foils due to the applied voltage as well as the flux of the incident particles. In this paper, we report the effect on gain stability of triple GEM detectors due to the polarising field induced by X-rays on the polyimide foils. Also, reducing the size of the amplifying structure to the microscopic scale results in a quick mitigation of the space charge effects which in turn helps in attaining a stable gain at very high incident flux. We report on the measurements of variations in the effective gain at very high particle flux of the order of MHz/mm2.
DOI: 10.1088/1748-0221/15/10/p10013
2020
Cited 4 times
Triple-GEM discharge probability studies at CHARM: simulations and experimental results
The CMS muon system in the region with 2.03<|η|<2.82 is characterized by a very harsh radiation environment which can generate hit rates up to 144 kHz/cm2 and an integrated charge of 8 C/cm2 over ten years of operation. In order to increase the detector performance and acceptance for physics events including muons, a new muon station (ME0) has been proposed for installation in that region. The technology proposed is Triple—Gas Electron Multiplier (Triple-GEM), which has already been qualified for the operation in the CMS muon system. However, an additional set of studies focused on the discharge probability is necessary for the ME0 station, because of the large radiation environment mentioned above. A test was carried out in 2017 at the Cern High energy AcceleRator Mixed (CHARM) facility, with the aim of giving an estimation of the discharge probability of Triple-GEM detectors in a very intense radiation field environment, similar to the one of the CMS muon system. A dedicated standalone Geant4 simulation was performed simultaneously, to evaluate the behavior expected in the detector exposed to the CHARM field. The geometry of the detector has been carefully reproduced, as well as the background field present in the facility. This paper presents the results obtained from the Geant4 simulation, in terms of sensitivity of the detector to the CHARM environment, together with the analysis of the energy deposited in the gaps and of the processes developed inside the detector. The discharge probability test performed at CHARM will be presented, with a complete discussion of the results obtained, which turn out to be consistent with measurements performed by other groups.
DOI: 10.1109/tns.2018.2871428
2018
Cited 3 times
Operational Experience With the GEM Detector Assembly Lines for the CMS Forward Muon Upgrade
The CMS Collaboration has been developing large-area triple-gas electron multiplier (GEM) detectors to be installed in the muon Endcap regions of the CMS experiment in 2019 to maintain forward muon trigger and tracking performance at the High-Luminosity upgrade of the Large Hadron Collider (LHC); 10 preproduction detectors were built at CERN to commission the first assembly line and the quality controls (QCs). These were installed in the CMS detector in early 2017 and participated in the 2017 LHC run. The collaboration has prepared several additional assembly and QC lines for distributed mass production of 160 GEM detectors at various sites worldwide. In 2017, these additional production sites have optimized construction techniques and QC procedures and validated them against common specifications by constructing additional preproduction detectors. Using the specific experience from one production site as an example, we discuss how the QCs make use of independent hardware and trained personnel to ensure fast and reliable production. Preliminary results on the construction status of CMS GEM detectors are presented with details of the assembly sites involvement.
DOI: 10.1007/978-3-319-73171-1_139
2018
Cited 3 times
Muon Chamber Endcap Upgrade of the CMS Experiment with Gas Electron Multiplier (GEM) Detectors and Their Performance
As the CERN LHC is heading towards a high luminosityHigh luminosity phase a very high flux is expected in the endcaps of the CMS Detector. The presence of muons in collision events can be due to rare or new physics so it is important to maintain the high trigger efficiency of the CMS muon system. The CMS Collaboration has proposed to instrument the high- $$\eta $$ region (1.6 $$< \mid \eta \mid<$$ 2.2) of the muon endcaps with Gas Electron Multiplier (GEM)Gas Electron Multiplier (GEM) detectors, referred to as GE1/1 chambers, during the LS2. This technology will help in maintaining optimum trigger performance with maximum selection efficiency of muons even in a high flux environment. We describe plans for a “Slice Test” to install a few GE1/1 chambers covering 50 $$^\circ $$ in azimuthal angle within the CMS detector in 2017, with subsequent operation during the current Run 2 of the LHC. We show the performance of the GE1/1 chambers to be installed during the slice test, specifically: GEM foil leakage currentsLeakage Current, chamber gas volume integrity, high voltageHigh voltage (HV) circuit performance, and effective gain.
DOI: 10.1088/1748-0221/15/02/p02003
2020
Cited 3 times
Development and qualification of triple-GEM detector built with large size single mask foils produced in India
The Gas Electron Multiplier (GEM) is the new age detector for nuclear and particle physics experiments, which was first developed by the European Center for Nuclear Research (CERN). It is comprised of an excellent insulator (Kapton/Apical) having a thickness of 50 μm which is covered with 5 μm copper layer on both sides and pierced by a regular array of holes. From its invention, CERN has been the sole supplier of the GEM foils until recently when few private companies started manufacturing GEM foils under the transfer of technology (TOT) from CERN. However, it's a long process to validate the foils delivered by these companies to claim that the GEM detectors made from them are compatible with high scientific standards. Along these lines, an India based company Micropack Pvt. Ltd. began fabricating both double and single mask GEM foils; at first Micropack produced 10 × 10 cm2 double mask foils which were tested both at foil and detector level by University of Delhi (DU) and it was confirmed to satisfy the required standards. Because of the double mask technique, the size of the GEM foil was constantly constrained so to overcome the confinement in size of GEM foils the single mask technique was developed in 2010. Micropack produced the first batch of 30 × 30 cm2 single mask foils in a joint effort with DU. A triple-GEM detector was constructed using these foils to test the fundamental quality controls, which include effective gain measurement, energy spectrum, and gain uniformity. Along with this, we will also report on the few advance studies which include discharge probability, rate capability, and charging up for this detector and foils.
DOI: 10.36106/ijar/2304941
2023
ASSESSMENT OF QUALITY OF SLEEP AND ITS ASSOCIATION WITH SOCIODEMOGRAPHIC AND CLINICAL FACTORS AMONG MEDICAL UNDER GRADUATES: A CROSS-SECTIONAL STUDY
Background- Sleep is a very important physiological process for many restorative functions. For maintaining the body's circadian rhythm sleep is essential. Reduced sleep quality can lead to excessive daytime sleepiness result in impaired daytime function, increased health problem, reduced work performance and impaired quality of life. A cross-sectional study was Methodsconducted among 590 medical undergraduates pursuing medical course. Blood pressure and anthropometric measurements of participants were recorded while Pittsburgh sleep quality index (PSQI) study tool was used to assess the sleep quality of medical undergraduates. Out of Results590 medical students, males and females were 60.7% and 39.3% respectively. 51% study subjects had poor sleep quality (PSQI score 5) with the mean global PSQI score of 6.44±1.80. The proportion of poor sleep quality among hypertensive and overweight/ obese medical students were 60.6% and 54% respectively. A statistically signicant association of sleep quality was found with gender (p= 0.033) and hypertension (p=0.027). It was also observed that 164 (27.8%) of study subjects had a sleep latency of more than 30 minutes while 196 (33.2%) had sleep duration less than 6 hours. Sleep efciency of more than 85% was observed among 576 (97.6%) of the study subjects and 542 (91.9%) did not use any sleep medicine during the past 1 month Conclusion: A high prevalence of poor sleep quality was found among medical undergraduate students.
DOI: 10.1016/j.nima.2023.168723
2023
Production and validation of industrially produced large-sized GEM foils for the Phase-2 upgrade of the CMS muon spectrometer
The upgrade of the CMS detector for the high luminosity LHC (HL-LHC) will include gas electron multiplier (GEM) detectors in the end-cap muon spectrometer. Due to the limited supply of large area GEM detectors, the Korean CMS (KCMS) collaboration had formed a consortium with Mecaro Co., Ltd. to serve as a supplier of GEM foils with area of approximately 0.6 m2. The consortium has developed a double-mask etching technique for production of these large-sized GEM foils. This article describes the production, quality control, and quality assessment (QA/QC) procedures and the mass production status for the GEM foils. Validation procedures indicate that the structure of the Korean foils are in the designed range. Detectors employing the Korean foils satisfy the requirements of the HL-LHC in terms of the effective gain, response uniformity, rate capability, discharge probability, and hardness against discharges. No aging phenomena were observed with a charge collection of 82 mC cm−2. Mass production of KCMS GEM foils is currently in progress.
DOI: 10.1088/1748-0221/18/11/p11029
2023
Impact of magnetic field on the stability of the CMS GE1/1 GEM detector operation
Abstract The Gas Electron Multiplier (GEM) detectors of the GE1/1 station of the CMS experiment have been operated in the CMS magnetic field for the first time on the 7 th of October 2021. During the magnetic field ramps, several discharge phenomena were observed, leading to instability in the GEM High Voltage (HV) power system. In order to reproduce the behavior, it was decided to conduct a dedicated test at the CERN North Area with the Goliath magnet, using four GE1/1 spare chambers. The test consisted in studying the characteristics of discharge events that occurred in different detector configurations and external conditions. Multiple magnetic field ramps were performed in sequence: patterns in the evolution of the discharge rates were observed with these data. The goal of this test is the understanding of the experimental conditions inducing discharges and short circuits in a GEM foil. The results of this test lead to the development of procedure for the optimal operation and performance of GEM detectors in the CMS experiment during the magnet ramps. Another important result is the estimation of the probability of short circuit generation, at 68 % confidence level, p short HV OFF = 0.42 -0.35 +0.94 % with detector HV OFF and p short HV OFF &lt; 0.49% with the HV ON. These numbers are specific for the detectors used during this test, but they provide a first quantitative indication on the phenomenon, and a point of comparison for future studies adopting the same procedure.
DOI: 10.1109/nssmicrtsd49126.2023.10338476
2023
mPMT photosensors development for the Water Cherenkov Test Experiment (WCTE)
In this work, we will discuss the development of mPMT photosensors for the Water Cherenkov Test Experiment (WCTE), which is set to operate in CERN's East Area T9 beam line. One of the primary objectives of WCTE development is to comprehend the technology and potential obstacles and apply it to Hyper-Kamiokande (Hyper-K) and its Intermediate Water Cherenkov Detector (IWCD). These mPMT modules are built using nineteen 3-inch PMTs, which allow the efficient detection of the Cherenkov radiation produced in the fiducial volume. We report on the novel procedure developed to build the mPMT modules and a concise overview of their mechanical and electronic components. Multiple tests were conducted on both the individual module components and the mPMT as a whole to validate the technology. These tests included optical scanning, pressure testing, and more. The WCTE operation is scheduled to begin in early 2024, with the production of mPMTs set to be completed by November 2023.
DOI: 10.1007/978-3-319-73171-1_22
2018
Various Studies with Gas Electron Multiplier (GEM) Detectors
High Energy Physics experiments are currently entering a new era which requires the operation of gaseous particle detectors at unprecedented high rates and integrated particle fluxes. Gas Electron Multiplier (GEM) introduced in 1997, constitutes a powerful addition to the family of fast radiation detectors. They allow to achieve both excellent localization accuracy and high rate capability that make this technology attractive for charged particle tracking at high luminosity colliders. Improvements in the performance of the GEM detectors were achieved by stacking more than one GEM foil inside the detector. A summary of the studies performed on $$10\,\mathrm{cm} \times 10\,\mathrm{cm}$$ Triple GEM detector and its performance is presented. We also report on performance of the $$100\,\mathrm{cm} \times 45\,\mathrm{cm} \times 22\,\mathrm{cm}$$ GEM detector such as GEM foil leakage currents, high voltage circuit performance, and effective gain. Along with that we describe some studies related to gas purity using Gas Chromatograph.
DOI: 10.1088/1742-6596/1498/1/012054
2020
CMS phase-II upgrade with GEM detector
Abstract The Large Hadron Collider (LHC) will be upgraded in several phases that will allow significant expansion of its physics program. The final luminosity of the accelerator is expected to exceed 5 × 10 34 cm −2 s −1 , five times more than the original design value. The CMS muon system must be able to sustain a physics program after the increase of luminosity and maintain sensitivity for electroweak physics for TeV scale searches similar to what was achieved up to now. To cope with the corresponding increase in background rates and trigger requirements, the installation of additional sets of muon detectors based on Gas Electron Multiplier (GEM) technology, referred to as GE2/1 and ME0, has been planned. The installation and commissioning of the GE2/1 chambers is scheduled in 2022, and for ME0 detectors are expected to be installed between 2022 to 2024. We present an overview of the Muon Spectrometer upgrade using GEM technology, a detailed description of the GE2/1 and ME0 upgrade in terms of design, pre-production chambers, mechanics, installation services etc. We will focus in particular on the novel solutions adopted for realization of the latter project, with a summary of the ongoing R&amp;D activities
DOI: 10.1088/1742-6596/1561/1/012006
2020
Two years’ test of a temperature sensing system based on fibre Bragg grating technology for the CMS GE1/1 detectors
Abstract A temperature monitoring system based on fibre Bragg grating (FBG) fibre optic sensors has been developed for the gas electron multiplier (GEM) chambers of the Compact Muon Solenoid (CMS) detector. The monitoring system was tested in prototype chambers undergoing a general test of the various technological solutions adopted for their construction. The test lasted about two years and was conducted with the chambers being installed in the CMS detector and operated during regular experimental running. In this paper, we present test results that address the choice of materials and procedures for the production and installation of the FBG temperature monitoring system in the final GEM chambers.
DOI: 10.1088/1748-0221/15/12/p12019
2020
Interstrip capacitances of the readout board used in large triple-GEM detectors for the CMS Muon Upgrade
We present analytical calculations, Finite Element Analysis modelling, and physical measurements of the interstrip capacitances for different potential strip geometries and dimensions of the readout boards for the GE2/1 triple-Gas Electron Multiplier detector in the CMS muon system upgrade. The main goal of the study is to find configurations that minimize the interstrip capacitances and consequently maximize the signal-to-noise ratio for the detector. We find agreement at the 1.5–4.8% level between the two methods of calculations and on the average at the 17% level between calculations and measurements. A configuration with halved strip lengths and doubled strip widths results in a measured 27–29% reduction over the original configuration while leaving the total number of strips unchanged. We have now adopted this design modification for all eight module types of the GE2/1 detector and will produce the final detector with this new strip design.
DOI: 10.1007/978-3-319-73171-1_186
2018
A Novel Assembly Procedure of GE1/1 Detectors for CMS High Luminosity Phase of the LHC
The CMS muon group is investigating the possibility of enhancing muon tracking and triggering capabilities in the region 1.6 $$|$$ $$\eta $$ $$|$$ 2.18 of the CMS experiment at the LHC by instrumenting the end-cap muon system with large-area tipple GEM detectors. These GE1/1 detectors are considered as an important technology for High-Luminosity phase of the LHC and contain a triple-GEM with a 3/1/2/1 mm drift/transfer-1/transfer-2/induction field gap configuration and the active readoutReadout area of 0.345/0.409 m $$\times $$ m for the short/long chambers. We describe a novel assembly procedure of such detectors at LHC.
DOI: 10.1007/978-3-319-73171-1_217
2018
Design and Development of Gas Leakage Station for Gas Electron Multiplier (GEM) Chamber
CMS GEMGas Electron Multiplier (GEM) collaboration is planning to upgrade its GE1/1 station of end cap using GEM detectors to improve spatial and timing resolution for its high luminosityHigh luminosity phase. The GEM detectors will be assembled and subjected to series of quality control (QC) tests before they will be finally used in CMS. Among the various quality control (QC) tests, gas leak test is very important for the GEM detectors to qualify their use in CMS. We describe in detail design and construction of gas leakageGas Leakage Station setup primarily using electronic and pneumatic components. The setup measures pressure drop in the detector using a gauge pressure sensor interfaced with PC through Arduino board.
2020
A new technique to establish the uniformity of the induction gap in GEM based detector.
This work is proposing and exploring the use of multichannel readout electronics, already used in quality assurance for gain uniformity studies, to measure the uniformity of the induction gap in GEM based detectors. The measurement will furthermore provide a qualification of the readout electrodes in terms of disconnected or shorted channels. The proposed method relies on the dependence on the induction gap capacitance between the readout strips and the bottom of the GEM. The measurement is obtained inducing capacitively a signal on the readout strips pulsing the bottom layer of the GEM foil. In this work, the signals are read with the analog APV25 front-end chip and the RD51 Scalable Readout System (SRS). Studies on small and large area GEM detectors, relative variations under mechanical stress, and in presence of electrical fields will be shown. Sensitivity to defects in the readout plane will be proven.
DOI: 10.1007/978-981-33-4408-2_174
2021
Design and Development of Gas Mixing Unit for Gas Electron Multiplier (GEM) Chamber
Gaseous detectorsKumar, Hemant are the important components in each High Energy Physics (HEP) Experiment [1]. The operation of such detectors depends upon the mixture of various gases such as Ar, CO $$_2$$ , CF $$_4$$ , etc.Ahmed, Asar However, the purity and the appropriate mixture of these gases is always the key component andGola, Mohit has a direct impact on various properties of the detectors like gain, spatial, timing, and energy resolutions. The present work describes the design andAhmed, Rizwan construction of flexible and cost-effective Gas Mixing Unit (GMU) which is very useful for providing the appropriate mixture to various gaseous detectors like drift tubes (DTs),Kumar, Ashok Gas Electron Multipliers (GEMs), Resistive Plate Chambers (RPCs), etc. We also present some preliminary results to demonstrate its stability with the changes in ambient conditions. The results were obtained by using this newly developed GMU with GEM 10 cm $$\times $$ 10 cm as a test detector.Naimuddin, Md.
2021
Performance of a Triple-GEM Demonstrator in $pp$ Collisions at the CMS Detector
The Phase-II high luminosity upgrade to the Large Hadron Collider (LHC) is planned for 2023, significantly increasing the collision rate and therefore the background rate, particularly in the high $\eta$ region. To improve both the tracking and triggering of muons, the Compact Muon Solenoid (CMS) Collaboration plans to install triple-layer Gas Electron Multiplier (GEM) detectors in the CMS muon endcaps. Demonstrator GEM detectors were installed in CMS during 2017 to gain operational experience and perform a preliminary investigation of detector performance. We present the results of triple-GEM detector performance studies performed in situ during normal CMS and LHC operations in 2018. The distribution of cluster size and the efficiency to reconstruct high $p_T$ muons in proton--proton collisions are presented as well as the measurement of the environmental background rate to produce hits in the GEM detector.
DOI: 10.1016/j.nima.2021.165826
2021
A new technique to establish the uniformity of the induction gap in GEM based detectors
This work explores the use of multichannel readout electronics, already in use for quality assurance in gain uniformity studies, to measure the uniformity of the induction gap in Gas Electron Multipliers (GEM) based detectors. The devised procedure also provides a qualification of the readout electrodes in terms of disconnected or shorted channels. The measurement is based on inducing a signal on the readout strips by pulsing the bottom layer of the GEM foil, and measuring the amplitude of the induced signal. In this work, signals are readout using the analog APV25 front-end chip and the Scalable Readout System (SRS) developed by the RD51 collaboration at CERN. Studies on small and large area GEM detectors, effects of mechanical stress, and of electric fields are presented. Sensitivity to defects in the readout plane is also verified.
DOI: 10.1088/1748-0221/16/12/p12026
2021
Benchmarking LHC background particle simulation with the CMS triple-GEM detector
Abstract In 2018, a system of large-size triple-GEM demonstrator chambers was installed in the CMS experiment at CERN's Large Hadron Collider (LHC). The demonstrator's design mimicks that of the final detector, installed for Run-3. A successful Monte Carlo (MC) simulation of the collision-induced background hit rate in this system in proton-proton collisions at 13 TeV is presented. The MC predictions are compared to CMS measurements recorded at an instantaneous luminosity of 1.5 ×10 34 cm -2 s -1 . The simulation framework uses a combination of the FLUKA and GEANT4 packages. FLUKA simulates the radiation environment around the GE1/1 chambers. The particle flux by FLUKA covers energy spectra ranging from 10 -11 to 10 4 MeV for neutrons, 10 -3 to 10 4 MeV for γ's, 10 -2 to 10 4 MeV for e ± , and 10 -1 to 10 4 MeV for charged hadrons. GEANT4 provides an estimate of the detector response (sensitivity) based on an accurate description of the detector geometry, the material composition, and the interaction of particles with the detector layers. The detector hit rate, as obtained from the simulation using FLUKA and GEANT4, is estimated as a function of the perpendicular distance from the beam line and agrees with data within the assigned uncertainties in the range 13.7-14.5%. This simulation framework can be used to obtain a reliable estimate of the background rates expected at the High Luminosity LHC.
1981
Theoretical scintillation spectra of the in-phase and quadrature wave components
1985
Model of Mid-Latitude Ionospheric Electron Content at Minium Solar Activity
1986
HiLat scintillation measurements at Spitsbergen