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 uRWELL 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.

The PICOSEC Micromegas (MM) detector is a precise timing gaseous detector based on a MM detector operating in a two-stage amplification mode and a Cherenkov radiator. Prototypes equipped with cesium iodide (CsI) photocathodes have shown promising time resolutions as precise as 24 picoseconds (ps) for Minimum Ionizing Particles. However, due to the high hygroscopicity and susceptibility to ion bombardment of the CsI photocathodes, alternative photocathode materials are needed to improve the robustness of PICOSEC MM. Diamond-like Carbon (DLC) film have been introduced as a novel robust photocathode material, which have shown promising results. A batch of DLC photocathodes with different thicknesses were produced and evaluated using ultraviolet light. The quantum efficiency measurements indicate that the optimized thickness of the DLC photocathode is approximately 3 nm. Furthermore, DLC photocathodes show good resistance to ion bombardment in aging test compared to the CsI photocathode. Finally, a PICOSEC MM prototype equipped with DLC photocathodes was tested in muon beams. A time resolution of around 42 ps with a detection efficiency of 97% for 150 GeV/c muons were obtained. These results indicate the great potential of DLC as a photocathode for the PICOSEC MM detector.

The PICOSEC Micromegas detector is a precise timing gaseous detector based on a Cherenkov radiator coupled to a semi-transparent photocathode and a Micromegas amplifying structure. First single-pad prototypes demonstrated a time resolution below sigma = 25 ps, however, to make the concept appropriate to physics applications, several developments are required. The objective of this work was to achieve an equivalent time resolution for a 10 x 10 cm(2) area PICOSEC Micromegas detector. The prototype was designed, produced and tested in the laboratory and successfully operated with a 80 GeV/c muon beam. Preliminary results for this device equipped with a CsI photocathode demonstrated a time resolution below sigma = 25 ps for all measured pads. The time resolution was reduced to be below sigma = 18 ps by decreasing the drift gap to 180 mu m and using dedicated RF amplifier cards as new electronics. The excellent timing performance of the single-channel proof of concept was not only transferred to the 100-channel prototype, but even improved, making the PICOSEC Micromegas detector more suitable for large-area experiments in need of detectors with high time resolutions.

Timing information in current and future accelerator facilities is important for resolving objects (particle tracks, showers, etc.) in extreme large particles multiplicities on the detection systems. The PICOSEC Micromegas detector has demonstrated the ability to time 150 GeV muons with a sub-25 ps precision. Driven by detailed simulation studies and a phenomenological model which describes stochastically the dynamics of the signal formation, new PICOSEC designs were developed that significantly improve the timing performance of the detector. PICOSEC prototypes with reduced drift gap size (∼119 µm) achieved a resolution of 45 ps in timing single photons in laser beam tests (in comparison to 76 ps of the standard PICOSEC detector). Towards large area detectors, multi-pad PICOSEC prototypes with segmented anodes has been developed and studied. Extensive tests in particle beams revealed that the multi-pad PICOSEC technology provides also very precise timing, even when the induced signal is shared among several neighbouring pads. Furthermore, new signal processing algorithms have been developed, which can be applied during data acquisition and provide real time, precise timing.

The Multi-gap Resistive Plate Chamber (MRPC) has been used in many high energy physics and nuclear experiments in the last decade, such as ALICE [1] and STAR [2]. Normally, the MRPC is built with commercial floating glass (bulk resistivity ρ≈ 1012Ω· cm), which limits the rate capability to less than 1 kHz/cm2. In modern high energy physics, with the increase of colliders beam energy and luminosity, the rate capability of MRPC has to be enhanced accordingly. One normal way is to decrease the bulk resistivity ρ of the resistive plate, as the low resistive glass developed by Tsinghua University for the CBM experiment [3]. Alternatively, the surface of the electrode is also a possible path for the neutralization of the avalanche charges. Recently, we managed to carry this method out by coating a Diamond-Like-Carbon (DLC) layer on the surface of the floating glass. The DLC layer, realized by the magnetron sputtering method, has very good physical and chemical stability. The demanded surface resistivity can be achieved easily. A series of DLC-coated glasses with different resistivity has been tested in our lab. We have also made some MRPC prototypes and tested them with cosmic rays. Some preliminar results, including the operating current, the efficiency and the time resolution, have been achieved. More research is ongoing to improve the design and performance of this new method of increasing the rate capability of MRPC.

The PICOSEC Micromegas detector can time the arrival of Minimum Ionizing Particles with a sub-25 ps precision. A very good timing resolution in detecting single photons is also demonstrated in laser beams. The PICOSEC timing resolution is determined mainly by the drift field. The arrival time of the signal and the timing resolution vary with the size of the pulse amplitude. Detailed simulations based on GARFIELD++ reproduce the experimental PICOSEC timing characteristics. This agreement is exploited to identify the microscopic physical variables, which determine the observed timing properties. In these studies, several counter-intuitive observations are made for the behavior of such microscopic variables. In order to gain insight on the main physical mechanisms causing the observed behavior, a phenomenological model is constructed and presented. The model is based on a simple mechanism of "time-gain per interaction" and it employs a statistical description of the avalanche evolution. It describes quantitatively the dynamical and statistical properties of the microscopic quantities, which determine the PICOSEC timing characteristics, in excellent agreement with the simulations. In parallel, it offers phenomenological explanations for the behavior of these microscopic variables. The formulae expressing this model can be used as a tool for fast and reliable predictions, provided that the input parameter values (e.g. drift velocities) are known for the considered operating conditions.

The multi-pad PICOSEC-Micromegas is an improved detector prototype with a segmented anode, consisting of 19 hexagonal pads. Detailed studies are performed with data collected in a muon beam over four representative pads. We demonstrate that such a device, scalable to a larger area, provides excellent time resolution and detection efficiency. As expected from earlier single-cell device studies, we measure a time resolution of approximately 25 picoseconds for charged particles hitting near the anode pad centres, and up to 30 picoseconds at the pad edges. Here, we study in detail the effect of drift gap thickness non-uniformity on the timing performance and evaluate impact position based corrections to obtain a uniform timing response over the full detector coverage.

The spherical proportional counter is a gaseous detector used in a variety of applications, including direct dark matter and neutrino-less double beta decay searches. The ACHINOS multianode structure is a read-out technology that overcomes the limitations of single-anode read-out structures for large-size detectors and operation under high pressure. A resistive ACHINOS is presented, where the 3D printed central component is coated in a Diamond-Like Carbon (DLC) layer. The production and testing of the structure, in terms of stability and resolution, is described. Further applications in fundamental physics and industry are also discussed.

We developed resistive THGEM (RTGEM) films with diamond-like carbon (DLC), a robust resistive material with adjustable resistivity. The RTGEM films were manufactured by coating DLC layers on PCB via magnetron sputtering and then mechanically drilling holes. RTGEM detector prototypes with different configurations with sensitive area ranging from 5 × 5 cm2 to 20 × 100 cm2 were successfully fabricated. To achieve higher gain, resistive well (RWELL) detectors were introduced by coupling single-faced RTGEM to anode PCB via resistive DLC layers. The RTGEM manufacturing process is simpler and efficient compared with the conventional THGEM with metallic electrodes, making it suitable for large-scale production. The resistive material can limit the energy of discharges occurring at high gas gains, making the detectors more robust. The single-stage RTGEM detectors achieved gains >103 and demonstrated good long-term gain stability. A large-area RTGEM detector (active area: 20 × 100 cm2) had good gain uniformity (∼12%). RWELL detectors achieved gains >8 × 103. Detailed fabrication process and performance study results are presented in this article.

Thick gas electron multipliers (THGEM) exhibit a charging-up effect, causing detectors' gain evolution versus time. The simulation of charging-up process is helpful for better understanding of the detector's gain stability over time, which is important for the design and optimization of such detectors. Iterative simulation methods and algorithms based on the Garfield++ toolkit have been developed, and the results are in agreement with experimental observations. However, those simulation methods require hundreds of iterations and calculating the quantity of deposited charges on the insulator step by step, which has a high computing resource cost and is very time consuming. This work describes a fast iterative method to simulate the charging-up effect of THGEM. The method estimates the deposited charges by consecutively calculating the electric field on the dielectric surface, which is considered to directly contribute to the charge accumulation. The superposition theorem of static electric field is applied to update the electric field map of THGEM by surface charges. This efficient method only requires a few iterations before reaching gain stabilization. The detailed simulation process is described, and the simulation results fit the experimental data reasonably well.

Detectors with a time resolution of a few tens of picoseconds and long-term durability in high particle fluxes are necessary for an accurate vertex separation in future particle physics experiments. The PICOSEC-Micromegas detector concept is a Micro-Pattern Gaseous Detector (MPGD) based solution addressing this particular challenge. It is based on a Micromegas detector coupled to a Cherenkov radiator and a photocathode. Primary electrons from the incident particles are generated in the photocathode and the time fluctuations due to different primary ionisation positions in the gaseous volume are reduced. The feasibility to reach a good time resolution using this concept was demonstrated in test beam studies, and time resolution values down to 24 ps were measured with muon beams at the CERN SPS accelerator complex. The previously simulated effects of different detector parameters on the time resolution were confirmed by measurements. For these measurements, a femtosecond laser system is used. For a single photoelectron, a time resolution of better than 50 ps is achieved mostly by minimising the drift gap distance. Furthermore, gain and Amplitude-to-Signal ratio (A/Q) with different gas mixtures are compared.

This contribution describes the PICOSEC-Micromegas detector which achieves a time resolution below 25ps. In this device the passage of a charged particle produces Cherenkov photons in a radiator, which then generate electrons in a photocathode and these photoelectrons enter a two-stage Micromegas with a reduced drift region and a typical anode region. The results from single-channel prototypes (demonstrating a time resolution of 24ps for minimum ionizing particles, and 76ps for single photoelectrons), the understanding of the detector in terms of detailed simulations and a phenomenological model, the issues of robustness and how they are tackled, and preliminary results from a multi-channel prototype are presented (demonstrating that a timing resolution similar to that of the single-channel device is feasible for all points across the area covered by a multi-channel device).

The spatial dependence of the timing performance of the R3809U-50 Micro-Channel-Plate PMT (MCP-PMT) by Hamamatsu was studied in high energy muon beams. Particle position information is provided by a GEM tracker telescope, while timing is measured relative to a second MCP-PMT, identical in construction. In the inner part of the circular active area (radius r<5.5 mm) the time resolution of the two MCP-PMTS combined is better than 10 ps. The signal amplitude decreases in the outer region due to less light reaching the photocathode, resulting in a worse time resolution. The observed radial dependence is in quantitative agreement with a dedicated simulation. With this characterization, the suitability of MCP-PMTS as t(0) reference detectors has been validated.

This work presents the concept of the PICOSEC-Micromegas detector to achieve a time resolution below 30 ps. PICOSEC consists of a two-stage Micromegas detector coupled to a Cherenkov radiator and equipped with a photocathode. The results from single-channel prototypes as well as the understanding of the detector in terms of detailed simulations and preliminary results from a multichannel prototype are presented.

Electrode sectorization is an important design principle for large area GEM based detectors. It reduces the energy of discharges and permits to disconnect defective or shorted sectors, but induces a local signal distortion and a potential efficiency loss. We implemented and evaluated a new design approach for the insulating gaps between electrode sectors, to minimize or mitigate distortions and dead regions. By preserving the hole pattern of GEMs even in the insulating region between electrode sectors, the response of the detector in these regions was partly recovered resulting in reduced distortions. Single-side sectored GEMs were optically read out to study the influence of different sectorization patterns. Recorded images show a clear improvement with full holes both aligned with the rows and with a random alignment as compared to the traditional blank insulating strip between sectors. A sectored GEM manufactured on a substrate coated with a resistive DLC layer was evaluated and shown to minimize distortions. The investigated sectorization patterns provide a way of recovering signals in the insulating or resistive regions between sectors in GEM-based detectors.

The PICOSEC-Micromegas detector was developed for precise timing of the arrival of charged particles with a resolution bellow 30 ps. This contribution, after a brief introduction presents results concerning the PICOSEC-Micromegas response to single photoelectrons, estimation of the photoelectron yield of various photocathode types, as well as its performance to time the arrival of test beam muons. In addition, results based on detailed simulation studies and a stochastic model developed for the understanding of the detector are presented. Finally, results of studies related to the development of large scale PICOSEC-Micromegas detector for practical applications are also presented, in particular, the timing performance of a multi-channel PICOSEC prototype.

An imaging hadron calorimeter with digital readout (DHCAL) using the micro-pattern gaseous detector (MPGD) technology is one of the hadron calorimeter options for the Circular Electron Positron Collider (CEPC). The sensitive detector of the CEPC DHCAL is required to be compact and highly efficient for MIPs with low hit multiplicity. A double-GEM detector and a resistive WELL (RWELL) detector based on the THGEM technique have been investigated as options for the DHCAL sensitive detector. A 030 cm × 3 cm double-GEM prototype with “3 mm-1 mm-1 mm” structure was built with the self-stretching technique to study the performance of the double-GEM detector for application to the CEPC DHCAL. The double-GEM prototype was read out with the MICROROC chip and tested with cosmic-rays. The results of the test show a detection efficiency higher than 95% and a hit multiplicity of 1.2. Compared with the GEM detector, the RWELL detector is advantageous in minimizing the dead area due to its simple assembly without stretching. In addition, it has a more compact structure than the double-GEM detector thanks to its single-stage gas amplification without any induction gap. A 25 cm × 25 cm RWELL prototype with a resistivie DLC electrode was developed by using the thermal bonding technique. And a fast grounding circuit was designed on its anode PCB to enhance the rate capability of the detector. Preliminary results from tests of the RWELL prototype with X-rays show that the detector could operate at a gain of 0∼800 with a 0∼2% uniformity, maintain such a gain when irradiated with 8 keV X-rays at a rate of 0∼30 kHz/cm2. Based on these results, the RWELL detector promises to be a good candidate as the sensitive detector of the CEPC DHCAL, which merits further studies.

The prospect of pileup induced backgrounds at the High Luminosity LHC (HL-LHC) has stimulated intense interest in developing technologies for charged particle detection with accurate timing at high rates. The required accuracy follows directly from the nominal interaction distribution within a bunch crossing (sigma(2) similar to 5 cm, sigma(t) similar to 170 ps). A time resolution of the order of 20-30 ps would lead to significant reduction of these backgrounds. With this goal, we present a new detection concept called PICOSEC, which is based on a "two-stage'' Micromegas detector coupled to a Cherenkov radiator and equipped with a photocathode. First results obtained with this new detector yield a time resolution of 24 ps for 150 GeV muons, and 76 ps for single photoelectrons.

A digital hadron calorimeter (DHCAL) has been proposed for precision jet-energy measurement by means of the particle flow algorithm for the experiment at the Circular Electron Positron Collider (CEPC). Among various candidate detector technologies for the sensitive layers of the CEPC-DHCAL, the gaseous electron multiplier (GEM) is an attractive option. A prerequisite for application of GEM to DHCAL is its scalability to very large size. The self-stretching technique is a novel method for assembling large-size GEM detectors, making it a promising GEM assembly technique in DHCAL application. As part of the R&D program for the CEPC-DHCAL, a double-GEM detector with an active area of 30 x 30 cm(2) has been constructed using the self-stretching technique. The double-GEM structure was adopted to better meet the requirement of compactness of DHCAL sensitive layers. The design and assembly of the double-GEM detector is described. Results from various tests of the detector with X-rays are also presented. Good performance of the double-GEM detector has been demonstrated for the DHCAL application.

An improved self-stretching technique is introduced to construct gaseous electron multiplier (GEM) chamber with size larger than 1 meter. This new assembly method, called as "sliding self-stretching", gives more uniform stretching force and better performance compared to its original version.