Triple Gas Electron Multiplier Research Articles

Secondary scintillation yield from GEM electron avalanches in - and --isobutane for CYGNO — Directional Dark Matter search with an optical TPC

CYGNO is an international collaboration with the aim of operating a ▪ optical time projection chamber (TPC) for directional Dark Matter (DM) searches and solar neutrino spectroscopy, to be deployed at the Laboratori Nazionali del Gran Sasso (LNGS). A ▪/▪ (60/40) mixture is used, along with a triple Gas Electron Multiplier (GEM) cascade to amplify the ionisation signal. The scintillation produced in the electron avalanches is read out using a scientific complementary metal–oxide–semiconductor (sCMOS) camera. This solution has proven to provide very high sensitivity to interactions in the few ▪ energy range. The inclusion of a hydrogen-based gas will offer an even lighter target, resulting in a more efficient energy transfer in a DM particle collision, and consequently, a lower detection threshold. Additionally, longer track lengths of light nuclear recoils are easier to detect with a clearer direction. However, the addition of such gas will contribute to quenching the scintillation, jeopardizing the TPC performance. In this work, we demonstrate the feasibility of adding 1% to 5% isobutane to the ▪/▪ (60/40) mixture by measuring the respective absolute scintillation yield output. The overall scintillation produced in the charge avalanches is not drastically suppressed by quenching due to the isobutane addition. The presence of Penning transfer from excited He atoms to isobutane molecules increases the number of electrons in the avalanches, partially compensating for the loss of scintillation due to quenching. For the highest applied GEM voltage, the total number of photons produced in the avalanche per ▪ deposited in the absorption region presents a decrease of only a factor of about three, from 2.30(20)×104 to 8.2(4)×103▪, as the isobutane content increases from 0 to 5%. The quantification of the visible component of the scintillation shows that isobutane quenches both visible and ultraviolet (UV) photons emitted by ▪/▪.

Investigation of the stability in the performance of triple GEM detectors for High Energy Physics experiments

Gas Electron Multiplier (GEM) is one of the mostly used technologies in the High Energy Physics (HEP) experiments. GEMs are widely used as tracking devices due to their high-rate handling capability and good position resolution.An initiative is taken to study the stability in performance of the GEM chamber prototypes in the laboratory using external radiation for Argon/CO2 gas mixture in 70/30 volume ratio. The effect of ambient parameters on the gain and energy resolution are studied. Very recently some behavioural changes in the performance of a single-mask GEM chamber is observed. The details of the experimental setup, methodology and results are reported here.

Observation on the bias current variation of a single mask triple GEM chamber

Gas Electron Multiplier (GEM) detector, one of the advanced members of the Micro Pattern Gas Detector (MPGD) group, is widely used in High Energy Physics (HEP) experiments. The high rate handling capability and spatial resolution make it a desired tracking detector for high rate HEP experiments. Investigation of the long-term stability is an essential criterion for any tracking device used in HEP experiments. To investigate the long-term stability of a Single Mask (SM) triple GEM detector prototype, it is irradiated continuously using a 55Fe X-ray source of energy 5.9 keV. The chamber is operated with Ar/CO2 gas mixture in continuous flow mode. The gain and energy resolution of the chamber are calculated from the 5.9 keV X-ray peak and studied as a function of time. The applied voltage, divider current and also the environmental parameters (ambient temperature, pressure and relative humidity) are recorded continuously. It is observed that at a fixed applied voltage, the divider current of the detector is changing with time and as a result, the gain of the detector also changes. A systematic investigation is carried out to understand the probable reasons behind the observed variation in divider current and also to find its possible remedies. The details of the experimental setup, methodology and results are discussed in this article.

Track-based alignment for the BESIII CGEM detector in the cosmic-ray test

The Beijing Electron Spectrometer III (BESIII) is a multipurpose detector operating on the Beijing Electron Positron Collider II (BEPCII). After more than ten years operation, the efficiency of the inner layers of the Main Drift Chamber (MDC) decreased significantly. To solve this issue, the BESIII collaboration is planning to replace the inner part of the MDC with three layers of Cylindrical triple Gas Electron Multipliers (CGEM).The transverse plane spatial resolution of CGEM is required to be 120μm or better. To meet this goal, a careful calibration of the detector is necessary to fully exploit the potential of the CGEM detector. In all the calibrations, the detector alignment plays an important role to improve the detector precision. The track-based alignment for the CGEM detector with the Millepede algorithm is implemented to reduce the uncertainties of the hit position measurement. Using the cosmic-ray data taken in 2020 with the two layers setup, the displacement and rotation of the outer layer with respect to the inner layer is determined by a simultaneous fit applied to more than 160000 tracks. A good alignment precision has been achieved that guarantees the design request could be satisfied in the future. A further alignment is going to be performed using the combined information of tracks from cosmic-ray and collisions after the CGEM is installed into the BESIII detector.

Characterization and Commissioning of a Triple-GEM Detector

We present in detail the characterization and commissioning of a triple Gas Electron Multiplier (triple-GEM)detector. The response to various sources of radiation was studied, and its efficiency, gain, energy resolution,and temporal resolution were calculated. We found an energy resolution of 19.5%, a temporal resolution of40 ns., and a maximum gain of 5×106. We conclude that the detector can be confidently used in furtherstudies of medical dosimetry, since it is working in the proportional mode.

Charging-up effect and uniformity study of a single mask triple GEM detector

The Gas Electron Multiplier (GEM) detector is one of the advanced members of the Micro Pattern Gas Detector (MPGD) family, used in High Energy Physics (HEP) experiments as a tracking device due to its high rate handling capability and good spatial resolution. The uniformity in the performance of the detector is an essential criterion for any tracking device.The presence of the dielectric medium (Kapton) inside the active volume of the GEM chamber changes its behaviour when exposed to external irradiation. This phenomenon is known as the charging-up effect. In this article, the charging-up effect over the entire surface of a Single Mask (SM) triple GEM chamber of dimension 10 cm × 10 cm is reported. The study of uniformity in terms of gain, energy resolution and count rate for the same chamber is also presented before and after the charging-up of the GEM foils.

Electronics for the far-forward CMS muon detector upgrade, ME0

With the High Luminosity upgrade of the Large Hadron Collider (LHC) we expect increased instantaneous luminosities up to 7.5 × 1034 cm−2 s−1, or five times more than the original values. In order to maintain performance of the Compact Muon Solenoid (CMS) experiment under these conditions, ME0 is one of three new muon sub-detectors being added, along with GE1/1 and GE2/1, which use the triple Gas Electron Multiplier (GEM) technology. ME0 is designed to cover the forward region of 2.0 < |η| < 2.8, thus improving muon reconstruction at high background rates by supplementing other overlapping muon subsystems up to |η| = 2.4, while also extending the acceptance for the first time to |η| = 2.8. The readout electronics for ME0 must be designed to accommodate high data rates and be sufficiently radiation hard to operate close to the beamline. The Optohybrid (OH) board for ME0, which reads out data from the front-end VFAT3b ASICs, has therefore been designed to operate without an FPGA (unlike GE1/1 and GE2/1) to ensure radiation hardness. The ME0 OH uses the radiation-hard CERN-designed lpGBT ASIC and VTRx+ optical transceiver module for high bandwidth optical links up to 10.24 Gb/s. The backend system is based on the ATCA standard. The design and development status of the readout electronics for ME0 is presented, along with recent results from integration tests performed using the first prototypes.

Development of readout electronics for the CMS ME0 muon detector

The Large Hadron Collider (LHC) in the High Luminosity (HL-LHC) era will be upgraded to deliver instantaneous luminosities up to 5 × 1 0 34 cm − 2 s − 1 , five times more than the original design value. In order to maintain performance of the Compact Muon Solenoid (CMS) Experiment under these conditions, ME0 is one of the new muon detectors to be added, along with GE1/1, GE2/1, RE3/1 and RE4/1. ME0 uses the triple Gas Electron Multiplier (GEM) technology and is designed to cover the far-forward region of 2 . 0 < | η | < 2 . 8 . The readout electronics for ME0 must be designed to deal with high data rates and be sufficiently radiation hard to operate very close to the beamline. The design and development status of the readout electronics for ME0 are presented, along with recent results from integration tests performed using the latest electronics prototypes with GEM chambers.

Radiation dosimetry with a Triple-GEM detector

We studied the properties of the gaseous detector triple-GEM (triple Gas Electron Multiplier) as a dosimeter with different ionizing radiation sources used in medical applications. The detector was calibrated in energy with an Iron-55 radioactive source. We measured doses of radiation from different radioactive sources as well as from a medical portable X-ray machine, and compared them to reference values. The detector presents a linear dependence between radiation intensity and measured dose. A calibration factor of 1.13x104 was found, independently of the radiation source. These results allow us to conclude that the triple-GEM detector has the potential to be used as a dosimeter in medical applications.

Effective Gain and Ion Back Flow study of triple and quadruple GEM detector

Gas electron Multipliers (GEM) are a new generation of gaseous avalanche devices in the Micro Pattern Gaseous Detector (MPGD) category. GEMs are widely used in both nuclear and high energy experiments as well as in medical science. Several parameters define the performance of these types of devices under various experimental conditions. This article focuses on the study of effective gain and Ion Back Flow (IBF) in both triple and quadruple GEM detectors. Effective gain and IBF are two of the most important parameters in determining the performance of GEM detectors.

Effect of relative humidity on the long-term operation of a single mask triple GEM chamber

The characteristic studies of a Single Mask (SM) triple Gas Electron Multiplier (GEM) detector are carried out using Ar/CO2 gas mixture in 70/30 volume ratio in continuous flow mode. A 55Fe X-ray source is used for this work. The gain and energy resolution are studied from the 5.9 keV X-ray energy spectra. After correcting the effects of ambient temperature and pressure variation, the effect of ambient relative humidity on the gain and energy resolution of the chamber is investigated. The details of the experimental setup, measurement methods and results are presented in this article.

Double-hit separation and dE/dx resolution of a time projection chamber with GEM readout

A time projection chamber (TPC) with micropattern gaseous detector (MPGD) readout is investigated as main tracking device of the International Large Detector (ILD) concept at the planned International Linear Collider (ILC). A prototype TPC equipped with a triple gas electron multiplier (GEM) readout has been built and operated in an electron test beam. The TPC was placed in a 1 T solenoidal field at the DESY II Test Beam Facility, which provides an electron beam up to 6 GeV/c. The performance of the readout modules, in particular the spatial point resolution, is determined and compared to earlier tests. New studies are presented with first results on the separation of close-by tracks and the capability of the system to measure the specific energy loss dE/dx. This is complemented by a simulation study on the optimization of the readout granularity to improve particle identification by dE/dx.

A Large Area GEMPix detector for treatment plan verification in hadron therapy

Quality Assurance in hadron therapy is crucial to ensure a safe and accurate dose delivery to the patients. This requires fast and reliable detectors with high spatial resolution. A first LaGEMPix prototype that combines a triple Gas Electron Multiplier and a highly pixelated readout based on a matrix of organic photodiodes coated on an oxide thin film transistor backplane has been built. The first version of the LaGEMPix has proven to have a limited spatial resolution, mainly attributed to the isotropic emission of the scintillation photons within the GEM holes. To improve the spatial resolution and confirm our predictions of the role of the photons, we built a new version of the detector with a reduced gap between the last GEM foil and the readout. Experimental results acquired using different methods and experimental set-ups show that the spatial resolution significantly improved with the new design.

High rate capability studies of triple-GEM detectors for the ME0 upgrade of the CMS Muon Spectrometer

The high-luminosity LHC (HL-LHC) upgrade is presenting new challenges for particle detector technologies. In the CMS Muon System gaseous detectors, the increase in luminosity will produce a particle background ten times higher than at the LHC. To cope with the high rate environment and maintain current performance, the triple-Gas Electron Multiplier technology is a promising candidate for high-rate capable detectors for the CMS-ME0 upgrade project in the innermost region of the forward Muon Spectrometer of the CMS experiment. An intense R&D and prototyping phase is currently ongoing to prove that such technology meets the stringent performance requirements of highly efficient particle detection in the harsh background environment expected in the innermost ME0 region. Here we describe the recent rate capability studies of triple-GEM detectors operated with an Ar/CO2 (70/30) gas mixture at an effective gas gain of 2 × 104 by using a high intensity 22 keV X-ray generator. Moreover, we present a novel foils design based on double-sided segmented GEM-foils, high voltage power distribution, and filtering, which the collaboration adopted for realization of the latter projects, and their impact on the performance of the detector in the light of new rate capability studies, with a summary of the ongoing R&D activities.

Present outcome from the NUMEN R&D phase

The NUMEN experiment aims at measuring double charge exchange reaction cross sections using heavy-ion beams of unprecedented intensity on specific isotopes. In order to get data-sets with good statistical significance from challengingly low cross sections it asks for the upgrade of the pre-existing magnetic spectrometer MAGNEX at INFN-LNS, in Catania. These reactions prove to be a way of getting information on the nuclear matrix elements of the neutrino-less double beta decay, the most promising probe to establish the Majorana or Dirac nature of the neutrino, and to evaluate the effective neutrino mass. A new setup for the target system is under development and adequate detectors are under study for the tracking and the identification of heavy ions at the expected rate up to 5 Mpps and for gamma-ray measurements. The tracker is a time projection chamber with electron amplification based on a triple Thick Gas Electron Multiplier (THGEM) foil, the particle identification is performed with telescopes composed of Silicon Carbide (SiC) and Thallium doped Cesium Iodide (CsI(Tl)) sensors, the gamma-ray detection is sustained with Cerium doped Lantanum Bromide (LaBr3(Ce)) scintillator detectors. Here a selection of results of the R&D phase and the integration study are presented.

Comparative study on charging-up of single, double and triple Gas Electron Multipliers (GEM)

In this paper, a detailed investigation has been carried out to understand the physics behind GEM charging-up and its effects on gain. Experiments have been performed on both double and triple GEM with the help of 55Fe X-ray source and a comparative study of these configurations along with the single GEM results observed in our previous work has been reported.The increase in gain due to polarization of GEM foil dielectric and reduction in gain due to charge accumulation on dielectric are studied for various field configurations and different radiation intensities.

Electronics integration for the GE2/1 and ME0 GEM detector systems for the CMS phase-2 muon system upgrade

The Large Hadron Collider is currently undergoing its High Luminosity upgrade, which is set to increase the instantaneous luminosity by about a factor of five. Consequently, the Compact Muon Solenoid experiment is upgrading its muon spectrometer to cope with the increased muon flux in the forward region. The GE2/1 triple-gas electron multiplier detector, which has recently entered the mass production phase, and the ME0 triple-GEM detector system, which is in the late prototyping phase, are undergoing electronics integration. These proceedings briefly discuss the frontend electronics for the GE2/1 and ME0 detector systems, the electronics integration testing process, and the future plans for the frontend electronics of these two detector systems by the CMS GEM collaboration.

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 2–3×1034 cm−2s−1 for Run 3 (starting in 2022), and it will be at least 5×1034 cm−2s−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.

High rate capability studies of triple-GEM detectors for the ME0 upgrade of the CMS muon spectrometer

The high-luminosity LHC (HL-LHC) upgrade is presenting new challenges for particle detector technologies. In the CMS muon system gaseous detectors, the increase in luminosity will produce a particle background ten times higher than at the LHC. To cope with the high rate environment and maintain current performance, the triple-gas electron multiplier technology is a promising candidate for high-rate capable detectors for the CMS-ME0 upgrade project in the innermost region of the forward muon spectrometer of the CMS experiment. An intense R&D and prototyping phase is currently ongoing to prove that such technology meets the stringent performance requirements of highly efficient particle detection in the harsh background environment expected in the innermost ME0 region. Here, we describe the recent rate capability studies of triple-GEM detectors operated with an Ar/CO2 (70/30) gas mixture at an effective gas gain of 2 × 104 by using a high intensity 22 keV X-ray generator. Moreover, we present a novel foil design based on double-sided segmented GEM-foils, high voltage power distribution and filtering, which the CMS muon collaboration adopted for realization of the CMS-ME0 project, and their impact on the performance of the detector in the light of new rate capability studies, with a summary of the ongoing R&D activities.

Simulation study of ternary gas mixture transport properties and their gain in GEM detectors used for muon tracking

Gas electron multiplier (GEM) has been installed in the high η region of the Compact Muon Solenoid experiment (CMS) because as example of its high-rate capability. The operational gas of the GEM plays an important role in providing an efficient detection of muon. This work aims to search for a safe and a high-performance gas mixture through a numerical study of the transport properties of ternary gas mixtures. The gas mixtures consists of a noble gas (Ar-Ne-Xe-He) mixed with CO2 and a third gas (N2-C5H12 -CH4 - iC4H10) with different proportions. The gain of single and triple GEM for the mixtures, which show optimal properties, is calculated to estimate their performance in the detector. It is found that the N2 included mixture is giving a high drift velocity while the C5H12 based mixture has the highest Townsend coefficient, which results in higher gain in both single and triple GEM.