Micro-pattern Gas Detectors Research Articles

TMM: Triple Micro-Mesh gaseous structure with ultralow ion backflow for gaseous photon detectors

Gaseous photomultiplier tubes sensitive to visible light and based on micro-pattern gaseous detectors have been widely investigated due to their wide range of potential applications. This study presents a novel triple micro-mesh gaseous structure (TMM) specifically designed for this purpose, featuring ultralow ion backflow (IBF). Prototypes of the TMM were manufactured and characterized with both an X-ray source and an ultraviolet laser, and the results demonstrated an unprecedented IBF ratio of 3 × 10−5 at gas gains exceeding 1 × 105, indicating a promising capability of TMMs for visible light detection.

Spatial resolution studies using point spread function extraction in optically read out Micromegas and GEM detectors

Optically read out gaseous detectors are used in track reconstruction and imaging applications requiring high granularity images. Among resolution-determining factors, the amplification stage plays a crucial role and optimizations of detector geometry are pursued to maximize spatial resolution. To compare Micro Pattern Gaseous Detector (MPGD) technologies, focused low-energy X-ray beams at the SOLEIL synchrotron facility were used to record and extract point spread function widths with MICRO-Mesh Gaseous Structure (icromegas) and Gas Electron Multiplier (GEM) detectors. Point spread function width of ≈108µm for Micromegas and ≈127µm for GEM foils were extracted. The scanning of the beam with different intensities, energies and across the detector active region can be used to quantify resolution-limiting factors and improve imaging detectors using MPGD amplification stages.

PICOSEC-Micromegas Detector, an innovative solution for Lepton Time Tagging

The PICOSEC-Micromegas (PICOSEC-MM) detector is a novel gaseous detector designed for precise timing resolution in experimental measurements. It eliminates time jitter from charged particles in ionization gaps by using extreme UV Cherenkov light emitted in a crystal, detected by a Micromegas photodetector with an appropriate photocathode. The first single-channel prototype tested in 150 GeV/c muon beams achieved a timing resolution below 25 ps, a significant improvement compared to standard Micropattern Gaseous Detectors (MPGDs). This work explores the specifications for applying these detectors in monitored neutrino beams for the ENUBET Project. Key aspects include exploring resistive technologies, resilient photocathodes, and scalable electronics. New 7-pad resistive detectors are designed to handle the particle flux. In this paper, two potential scenarios are briefly considered: tagging electromagnetic showers with a timing resolution below 30ps in an electromagnetic calorimeter as well as individual particles (mainly muons) with about 20ps respectively.

Optimization of GEM detectors for applications in X-ray fluorescence imaging

In this work a set of simulations that aim at the optimization of Micropattern Gaseous Detectors (MPGD) for applications in X-ray fluorescence imaging in the energy range of 3–30keV is presented. By studying the statistical distribution of electrons from interactions of X-rays with gases, the energy resolution limits after charge multiplication for 6keV X-ray photons in Ar/CO2(70/30) and Kr/CO2(90/10) were calculated, resulting in energy resolutions of 15.4(4)% and 14.6(2)% respectively. These two mixtures were studied in simulations to evaluate the advantages of using krypton-based mixtures to reduce the presence of escape peaks in fluorescence spectra. A model to evaluate the X-ray fluorescence from the conductive materials inside the detectors was implemented, serving as a tool to estimate the extent of contamination of fluorescence spectra when using copper or aluminum layers in the material composition of MPGDs.

Tracking performances of the ePIC detector at the Electron-Ion Collider

The ePIC (electron–Proton/Ion Collider) experiment is a future facility at the Electron-Ion Collider (EIC) complex, located at the Brookhaven National Laboratory, USA. It will use ∼70% longitudinally polarized beam of electrons, protons, and light ions to study their collisions to understand the properties of the quarks, gluons, and the strong force responsible for the formation of the nucleus. The layout of the central detector of the ePIC experiment is not symmetric along the beams axis consisting of barrel, forward, and backward detectors to achieve a wide pseudorapidity (|η|< 3.5) coverage. There are further far-forward and far-backward tracking detectors to measure the luminosity and reconstruct the particles and fragments for the study of the exclusive deep-inelastic scattering (DIS) processes. The experiment has a challenging environment due to the presence of the background radiations (synchrotron radiation, beam-gas interactions, minimum-bias events, etc.) which will produce additional background hits on the tracker. The synchrotron radiation is suppressed to some extent by coating the beampipe with a 5μm gold layer. The experiment uses state-of-the-art bent wafer-scale silicon monolithic active pixel sensors (MAPS) with a ∼5μs acquisition window, micro-pattern gas detector (MPGD) with a good time resolution (∼20–30ns), and time-of-flight detectors based on AC-LGAD sensors (time resolution ∼30ps). The timing information of each detector will play a crucial role in track finding and rejecting the background hits utilizing the 4-dimensional tracking (space, time) to ensure the excellent performance of the experiment. The article presents the expected tracking performance of the ePIC detector using the modular ePIC software stack for simulation, reconstruction, and analysis. The Geant4 toolkit is employed for full detector simulations, alongside DD4hep (Detector Description for High Energy Physics) for geometry definition and exchange. The reconstruction incorporates the JANA2 framework, in addition to the tracking and vertexing algorithms inherited from A Common Tracking Software (ACTS).

Development of high performance micro-Resistive Groove detector

The Micro-Resistive Groove (μRGroove) is a single-stage Micro-Pattern Gaseous Detector (MPGD) with a groove amplification pattern. The resistive protection electrode is Diamond-Like Carbon (DLC), ensuring the detector achieves gas gain (≥104) and maintains good stability. The top copper layer of the groove is strip-shaped and can be grounded for 1D-strip readout. Therefore, only an additional 1D-strip is required to achieve 2D spatial resolution. Because the 2D readout is divided on both sides of the amplification structure, the induced charge-sharing effect is avoided, effectively increasing the induced signal amplitude, which is beneficial for applications of large-area tracking and cylindrical MPGD. In this study, we present the design and performance of the 10cm×10cmμRGroove prototype, which can achieve an effective gain of 2×104, an energy resolution of approximately 25%, a maximum detection efficiency close to 98%, and 2D spatial resolution better than 80μm. It also introduces the 50cm×50cm large-area μRGroove, which shows preliminary results with a detection efficiency >96% and 2D spatial resolution better than 100μm, meeting the normal requirements for large-area tracking detection. Finally, it discusses the progress of the low-mass cylindrical μRGroove, with the first prototype having an effective area of 13.1cm in diameter and 10cm in length. Its energy resolution is ∼26% measured by 55Fe and further beam tests being planned. This design is expected to become a practical solution for the inner tracker of the STCF.

The [formula omitted]-RWELL technology for tracking apparatus in High Energy Physics

The micro-Resitive WELL (μ-RWELL) is a Micro Pattern Gas Detector (MPGD) that inherits some of the best characteristics of existing MPGDs, like GEMs and MicroMegas, while simplifying the detector construction. A significant progress towards large-scale applications has been achieved through the consolidation and industrial cost-effective manufacturing of this technology. The μ-RWELL, showing excellent spatial performance, good time resolution and stability under irradiation, is proposed for several tracking apparatus for future experiments at future accelerators such as FCC (CERN), CEPC (China) and EIC (Brookhaven National Laboratory). The reduced impact in terms of material budget makes this technology suitable for the development of tracking devices in the muon spectrometer. In addition, the flexibility of the μ-RWELL base material makes this device suitable for the development of very light, fully cylindrical inner trackers at future high luminosity tau-charm factories, SCTF (China). We report in this paper some results in the development of 2D readouts for IDEA apparatus and the construction steps of a cylindrical μ-RWELL.

Design and optimization of a hadronic calorimeter based on micropattern gaseous detectors for a future experiment at the Muon Collider

Micro-pattern gaseous detectors (MPGDs) are a promising readout technology for hadronic calorimeters (HCAL) thanks to their good spatial resolution, longevity and rate capability. We describe the development of a HCAL based on MPGDs for an experiment at the proposed Muon Collider. The design of a semi-digital MPGD-HCAL is shown and its performance is calculated with Monte Carlo simulations with high-energy pions, showing an energy resolution down to 8% for 80GeV pions. We also present the performance of twelve MPGD prototypes with different technologies (MicroMegas, μ-RWELL and RPWELL) assembled and operated in test beam first with high-energy muons and later with pions in a hadronic calorimeter prototype of ∼1λI length; the detectors have a good response uniformity (lower than 17%) and spatial resolution and their performance in the calorimeter shows very good agreement with the Monte Carlo shower calculation.

Corryvreckan framework integration for [formula omitted]-RWELL tracking detectors

This study is dedicated to enhancing the Corryvreckan framework, a versatile platform designed for the reconstruction and analysis of test beam data, by integrating an interface for the Scalable Readout System (SRS)+APV25 Front End Electronics (FEE). The SRS+APV25 represents the initial stage of a very popular readout chain for acquiring and processing Micro Pattern Gaseous Detectors (MPGD) signals. Initially, Corryvreckan was optimized by its developers for use with pixelated silicon-based detectors. This project, for the first time, aims to exploit all the potentialities of the Corryvreckan framework for the analysis of gaseous detectors data, specifically the μ-RWELL tracking detectors with strip readout. Detectors with different readout layouts were tested, thanks to the test beam carried out in June 2023 by the collaboration of FCC-ee, LHCb and CLAS12 groups. The analysis performed with Corryvreckan was benchmarked against the analysis conducted using the GRAAL framework, which is the standard tool currently employed, proving that Corryvreckan’s modular approach not only simplifies the process of adapting it to various types of detectors but also enhances the efficiency of data analysis by providing a streamlined, user-friendly interface.

Performance of a triple-GEM detector with capacitive-sharing 3-coordinate (X–Y–U)-strip anode readout

The concept of capacitive-sharing readout, described in detail in a previous study, offers the possibility for the development of high-performance three-coordinates (X–Y–U)-strip readout for Micro Pattern Gaseous Detectors (MPGDs) using simple standard PCB fabrication techniques. Capacitive-sharing (X–Y–U)-strip readout allows simultaneous measurement of the Cartesian coordinates x and y of the position of the particles together with a third coordinate u along the diagonal axis in a single readout PCB. This provides a powerful tool to address multiple-hit ambiguity and enable pattern recognition capabilities in moderate particle flux environment of collider or fixed target experiments in high energy physics HEP) and nuclear physics (NP). We present in this paper the performance of a 10 cm × 10 cm triple-GEM detector with capacitive-sharing (X–Y–U)-strip anode readout. Spatial resolutions of the order of σxres = 71.6±0.8μm for X-strips, σyres = 56.2±0.9μm for Y-strips and σures =75.2±0.9μm for U-strips have been obtained at a beam test at Thomas Jefferson National Accelerator Facility (Jefferson Lab). Modifications of the readout design of future prototypes to improve the spatial resolution and challenges in scaling to large-area MPGDs are discussed.

The micro-resistive groove detector: a new compact single amplification-stage MPGD

In this paper, we introduce a novel single amplification-stage Micro-Pattern Gaseous Detector (MPGD) that incorporates a Diamond-Like Carbon (DLC)-based resistive electrode at the bottom of micro-groove structures, the micro-Resistive Groove (μRGroove) detector. The μRGroove shares a similar compact stack geometry with the micro-Resistive WELL (μRWELL) detector, but it distinguishes itself by employing a groove structure for charge amplification instead of a well. The top metal layer of the grooves naturally forms an array of strips. By incorporating additional 1-dimensional (1D) readout strips beneath the DLC electrode, a 2-dimensional (2D) strip-readout scheme can be easily implemented. Two prototypes of the μRGroove (10 cm× 10 cm) were manufactured in 2022 at CERN, and their performance was evaluated through X-ray and beam tests. The results indicate a gas gain > 104, an energy resolution of ~ 25%, and negligible charging-up effects for 8 keV Cu X-rays. Additionally, the detection efficiency was found to be ~ 95%, with a position resolution of ∼ 75 μm for 150-GeV/c muons. The μRGroove boasts a compact design and robustness against discharges. Furthermore, compared to the μRWELL, it offers cost savings in detector fabrication and yields significantly higher signal amplitude (approximately double) at the same gas gain. These attributes position the μRGroove as a promising candidate for large-area and low-material-budget tracking applications.

Characterisation of resistive MPGDs with 2D readout

Micro-Pattern Gaseous Detectors (MPGDs) with resistive anode planes provide intrinsic discharge robustness while maintaining good spatial and time resolutions. Typically read out with 1D strips or pad structures, here the characterisation results of resistive anode plane MPGDs with 2D strip readout are presented. A µRWELL prototype is investigated in view of its use as a reference tracking detector in a future gaseous beam telescope. A MicroMegas prototype with a fine-pitch mesh (730 line-pairs-per-inch) is investigated, both for comparison and to profit from the better field uniformity and thus the ability to operate the detector more stable at high gains. Furthermore, the measurements are another application of the RD51 VMM3a/SRS electronics.

Studies on a hadronic calorimeter with MPGD technology for a future Muon Collider experiment

In the context of the European strategy for particle physics, the Multi-TeV Muon Collider has emerged as a compelling alternative for advancing our understanding of the Standard Model, after the full exploitation of the High-Luminosity LHC. The physics programme at the Muon Collider includes precise measurements in the Higgs boson sector and the search for new physics at the TeV scale. Achieving these goals relies on accurate full event reconstruction, including the identification and precise four-momentum estimation of various particles. The Particle Flow (PF) algorithm is one of the most suitable approach for this task, exploiting information from tracking, calorimeter, and muon detectors for particle identification and measurements of their momenta/energies. Tracking detectors measure charged particle momenta, while calorimeters provide energy measurements for photons and neutral hadrons. Therefore, a combination of an exceptional tracking system and high-granularity calorimeters is necessary. However, one of the biggest challenges for a future experiment at the Muon Collider is to discriminate the product of the μμ collisions from the intense beam-induced-background (BIB), due to the unstable nature of muons, whose decay products interact with the detector material. To address this, an innovative hadronic calorimeter (HCAL) based on Micro Pattern Gas Detectors (MPGDs) is proposed. MPGDs offer robust technology for high radiation environments and a high granularity for precise spatial measurements. Dedicated studies are needed to assess and optimize the performance of an MPGD-based HCAL, including the development of medium-scale prototypes for performance measurements. The response of HCAL to incoming particles is examined through Monte Carlo simulations using Geant4, comparing the performance of digital and semi-digital readouts, with energy resolution as the figure of merit. The simulated geometry will be integrated into the Muon Collider software to study its impact on jet reconstruction within the full apparatus and in the presence of BIB. The simulation will be also validated through the test of a small-size calorimeter cell equipped with advanced resistive MPGD technologies, namely resistive MicroMegas, resistive μRWELL and RP-WELL.

Highly radiation-stable DLC coatings for a new class of detectors: Structural and morphological features

Within the framework of the FTM-NEXT INFN (Fast Time Micropattern gaseous detectors - next of Nuclear Physics National Institute) experiment, we produced hydrogen-free diamond-like carbon films through pulsed-laser deposition to serve as resistive layers in modern resistive micro-pattern gaseous detectors that must work in extreme radiation environments at future colliders. To obtain homogeneous diamond-like carbon coatings, over medium-to-large size (3 cm × 3 cm), with excellent adhesion to the substrate and with typical surface resistivity values in the range of 1–100 MOhm/sq, growth conditions had to be optimized. In this paper we report on the stability of resistive diamond-like carbon layers subjected to increasing doses of irradiation with proton beams accelerated to an energy of 2 MeV. The morphological, structural, and electrical properties, also at the nanoscale level, of diamond-like carbon coatings following ion irradiation were studied by electron microscopy, electron diffraction, electrical transport characterization and scanning tunneling spectroscopy.

Noise in detectors containing distributed resistive elements

We discuss the thermal noise originating from distributed resistive materials in particle detectors like Resistive Plate Chambers or Resistive Micro-Pattern Gas Detectors. The complex impedance Z(f) of the detector as seen by the amplifier input terminal is the key number defining the noise power spectrum. We give some analytic examples and show how this number can be calculated for any detector geometry using numerical simulations programs.

Design and fabrication of low background, high energy resolution thermal bonding Micromegas detectors for the PandaX-III experiment

The high-pressure xenon time projection chamber (TPC) utilizing micro-pattern gaseous detector readout has emerged as a highly promising technical solution for the search of neutrino-less double beta decay events. This approach offers exceptional features, including high energy resolution, fine granularity, low background radioactivity, and scalability for large-scale experiments. In line with these advantages, the PandaX-III experiment aims to implement a 10 bar Xe136 TPC, employing a readout plane comprising 52 194 × 194 mm2 Micromegas detectors, within the China Jinping Underground Laboratory.To fulfill the stringent experimental requirements of PandaX-III, a low-background Micromegas detector with high energy resolution was proposed and developed using the thermal bonding method. The performance of the thermal bonding Micromegas prototypes was investigated using X-ray characterization under various gas mixtures with argon and isobutane from 1 bar to 10 bars. Remarkable results were presented at 1 bar gas pressure, where a maximum gas gain of ∼8 × 104 and the best energy resolution (FWHM @5.9 keV) of 13.6% is obtained, and at 10 bar pressure, where maximum gas gain exceeding 104, the best energy resolution of 19%, and excellent stability over a test duration exceeding 150 h is achieved.

First results on MPGD prototypes in test beam for MPGD-based HCAL at a future Muon Collider experiment

The Multi-TeV Muon Collider will allow significant advancement in particle physics and in the understanding of its Standard Model for the era after the High-Luminosity LHC. The Muon Collider physics program involves precise Higgs boson sector measurements and TeV-scale new physics exploration. These goals demand accurate full-event reconstruction. The Particle Flow algorithm, which utilizes tracking, calorimeter, and muon detectors, is ideal for identifying and precisely estimating particle momenta/energies and can accomplish this task. Tracking detectors measure charged particle momenta, while calorimeters provide energy measurements for photons and neutral hadrons. Therefore, combining an exceptional tracking system with high-granularity calorimeters is essential. A major challenge is discerning μμ collision products from beam-induced-background, due to muon decay. To address this, an innovative hadronic calorimeter (HCAL) using Micro Pattern Gas Detectors (MPGDs) is proposed. MPGDs provide robust technology for high radiation and ensure precise spatial measurements. Dedicated studies are needed to assess and optimize the performance of an MPGD-based HCAL, including the development of medium-scale prototypes for performance measurements.This article describes the studies for a hadronic calorimeter based on MPGDs, relying on advanced technologies such as μ-rwell, resistive MicroMegas, and RPWELL. To assess the performance of MPGD detectors, a test beam was conducted in July 2023 at the Super Proton Synchrotron at CERN. This test beam aimed to evaluate the performance of MPGD detectors with 1×1 cm2 pad readout under beam irradiation. Preliminary results from this test are presented.

Fast timing detectors for the muon system of a muon collider experiment: requirements from simulation and prototype performance

Looking at the future path of high-energy physics, a muon collider offers incomparable potential for discovery in the multi-TeV energy range. However, its development must address some relevant technological challenges, which arise from the short muon lifetime, 2.2 μs, and from the difficulty of producing large numbers of muons in groups with small emittance. The first one in particular leads to the production of the so-called Beam-induced Background (BIB), which affects the design of the machine and detector.The purpose of this contribution is to describe the expected performance of the muon system of a multipurpose muon collider detector designed to reconstruct the products of multi-TeV collisions with extreme accuracy.We are proposing a design of the muon system fully based on Micropattern Gaseous Detectors (MPGD), which foresees the combination of tracking layers based on Triple-GEM detectors, with a timing layer based on a new generation MPGD called Picosec. Picosec was developed in the last few years by the RD51 collaboration, with the aim of obtaining a fast timing (sub ns) MPGD.A dedicated R&D is ongoing to optimize such a technology for the application in a muon collider experiment, both from the detector and the mechanics point of views.This contribution will present the results obtained during the R&D of the Picosec technology for the muon collider both from laboratory tests and test beams performed in 2023. Special attention will be given to the performance obtained with different gas mixtures. Moreover, we will discuss the plans for the R&D dedicated to the muon collider.

New generation B-Field and RAD-tolerant DC/DC power converter for on-detector operation

The increase in the number of readout channels in new detectors, like the Micro Pattern Gas Detectors (MPGD), in the order of several millions, requires a large amount of electrical power to supply the front-end electronics, up to hundreds kW. If this power is generated at long distances from the detector, the voltage drop on the connection cables puts serious constraints to the supply current, to the wire cross-section and to the power distribution. A large amount of voltage drop on the cables, apart an increased power dissipation on wire resistance, determines regulation issues on the load in case of current transients. To mitigate these problems, a new generation DC/DC converter, working in a heavily hostile environment and with a power density greater than 200 W/dm3, was developed. It is modular, with up to four independent modules, eight channels each, collected in a water-cooled crate, and can supply the load with an adjustable 10 to 12 V output up to 170 W per channel. In this contribution, the design constraints of such a converter are analysed, taking as a basis the environmental, electrical and mechanical requirements of the ATLAS New Small Wheel (NSW) project. Thermal considerations require the converter to be water-cooled, and the dimensional constraints impose the adoption of an innovative design to convey the dissipated heat towards the heat exchanger. The control and monitoring system allows for the full remote management of the converter. Main electrical parameters were measured and are reported. The converter was also characterized in a harsh working environment, with radiation tests in the CERN CHARM facility beyond the limits estimated for ten years operation in ATLAS, and with magnetic field tests in various orientations, using different magnets at CERN up to 1.3 T. A better common mode noise filtering design improvement was implemented after the first characterization. Final performance measurements after the modifications are also reported.

The μ-RWELL in High Energy Physics and beyond

The μ-RWELL, a resistive Micro-Pattern Gaseous Detector with a single amplification stage, is crafted using a copper-clad polyimide foil intricately micro-patterned with a blind hole (well) matrix. This matrix is integrated into the readout Printed Circuit Board, complemented by a thin Diamond-Like-Carbon sputtered resistive film, in order to mitigate the transition from streamer to spark regimes, enabling the attainment of substantial gains (≥104). However, this arrangement diminishes the detector's capacity to withstand high particle fluxes.For low-rate applications, the simplest resistive configuration utilises a single resistive layer with edge grounding. This design, however, exhibits a non-uniform response under elevated particle irradiation. To overcome this behaviour, new current evacuation geometries have been developed. In this work, we examine the efficacy of various high-rate resistive layouts, trialled at the prestigious CERN H8-SpS and PSI πM1 beam testing facilities. These designs are tailored to meet the demanding requisites of detectors operating in the HL-LHC environment, as well as those of future experiments at the next generation colliders, such as the FCC-ee/hh and CepC.