The integration of resistive materials has fundamentally advanced Micro-Pattern Gaseous Detector (MPGD) technology, enabling robust, high-gain operation essential for modern particle physics experiments. Diamond-Like Carbon (DLC) has emerged as a superior material for this purpose due to its uniquely tunable electrical, mechanical, and chemical properties. This article provides a comprehensive review of the development, fabrication, and application of DLC-based resistive coatings for MPGDs, with a focus on work conducted by the University of Science and Technology of China MPGD group. We detail the material fundamentals of DLC, systematically introduce magnetron sputtering as the core deposition methodology, and analyze the critical relationship between coating properties—such as resistivity, uniformity, adhesion, and stability—and final detector performance. A thorough examination of specific detector architectures (μ-RWELL, μRGroove, THGEMs, RWELL, Picosecond Micromegas) demonstrates the transformative impact of DLC. Finally, we summarized the outstanding technical challenges and present a perspective on future research directions aimed at scaling this technology for next-generation experiments.

Resistive electrodes are a critical component of Micro-Pattern Gaseous Detectors (MPGDs) for dealing with discharges. This study introduces an advanced approach using germanium (Ge) thin films as resistive anodes in MPGDs. The Ge films are fabricated via vacuum thermal evaporation, which enables the production of large-area and uniform on rigid substrates. Characterization confirms the film stability for over 700 days, which is attributed to surface passivation. It also reveals an inverse correlation between resistivity and temperature. Micromegas detectors equipped with Ge resistive anodes achieve high gain, low spark rate and high rate capability. These results validate Ge-film resistive anodes as a reliable and scalable technology for improving the performance and stability of MPGDs in future particle physics experiments.

Micro-pattern gaseous detectors (MPGDs), when integrated with optical imaging sensors, have been proven to effectively and accurately capture radiation beam information. To address the challenges of monitoring the dose and profile of medical pencil proton beams (MPPB), which have a high density of greater than 109 Hz/cm2, an optical readout micro-mesh gaseous structure (ORM) was proposed. A Micromegas prototype was manufactured with a glass substrate coated with transparent indium tin oxide as the detector anode. Its effective area is 8 cm x 8 cm. The ORM was firstly characterized with an Iron-55 X-ray source (55Fe) and a silver target X-ray tube individually, good energy resolution of 14.5% (FWHM), high gain greater than 104, and spatial resolution of 400 mu m (10% MTF) were achieved. The prototype was then tested with the MPPB. The evaluation revealed linear dose responses exceeding 99% (R-squared value) for both single-point and nine-point beam spots at various beam energies and doses. The size and center position deviation of the nine-point spot measurement were within 0.35 mm and 1 mm, respectively, indicating the good potential of this method for MPPB spot quality assurance. Additionally, the ORM is expected to be expanded to monitor other types of high-flux beams, such as medical neutron and gamma beam inspections, by adding suitable conversion layers.

The PICOSEC Micromegas(MM)is a precise timing gaseous detector based on a Cherenkov radiator coupled with a semi-transparent photocathode and an MM amplifying structure.It features a two-stage amplification process that leads to a significant deterioration of non-uniformity when scaling up to larger areas.Since the performance of gaseous de-tectors is highly dependent on the choice of working gas,optimizing the gas mixture offers a promising solution to im-prove the uniformity performance.This paper addresses these challenges through a combined approach of simulation based on Garfield++and experimental studies.The simulation investigates the properties of different mixing fractions of gas mixtures and their impact on detector performance,including gain uniformity and time resolution.To verify the simu-lation results,experimental tests were conducted using a multi-channel PICOSEC MM prototype with different gas mix-tures.The experimental results are consistent with the findings of the simulation,indicating that a higher concentration of neon significantly improves the detector's gain uniformity.Furthermore,the influence of gas mixtures on time resolution was explored as a critical performance indicator.The study presented in this paper offers valuable insights for improving uniformity in large-area PICOSEC MM detectors and optimizing overall performance.

The electrode's resistivity is crucial for resistive gaseous detectors' rate capability. We developed a precise timing gaseous photodetector with a glass RPC structure (photo-RPC). The detector's rate capability and timing performance were measured with different resistive float glass. The results show that compared to the photo-RPC with a high-resistivity electrode, the detector with very low-resistivity (1.5 x 10(9) Omega cm) glass shows greatly improved rate capability, while the time resolution and gain remains unchanged.

High-precision time measurement electronics play a crucial role in many particle physics experiments. In this paper, the design and testing of RF-amplifier-based prototype electronics for the high-precision time measurement of fast signals are introduced. The effects of parameters such as bandwidth, noise performance, and gain on time precision are analyzed in this design. Based on the analysis, the pre-amplification circuit is optimized. Utilizing the optimized pre-amplification circuit and the Domino Ring Sampler (DRS4) chip with a sampling rate of 5.12 Gsps, the prototype electronics are developed. To evaluate the performance of the electronics, a series of tests were conducted using a high-speed pulse generator, achieving time precision better than 5 ps. Additionally, laser and beam tests were conducted using the electronics in combination with a fast-timing Micromegas detector. In the beam test, the time resolution of the overall system, including the electronics and detector, was better than 23 ps.

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 (mu RGroove) detector. The mu RGroove shares a similar compact stack geometry with the micro-Resistive WELL (mu RWELL) 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 mu RGroove (10 cm x 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 > 10(4), an energy resolution of similar to 25%, and negligible charging-up effects for 8 keV Cu X-rays. Additionally, the detection efficiency was found to be similar to 95%, with a position resolution of similar to 75 mu m for 150-GeV/c muons. The mu RGroove boasts a compact design and robustness against discharges. Furthermore, compared to the mu RWELL, it offers cost savings in detector fabrication and yields significantly higher signal amplitude (approximately double) at the same gas gain. These attributes position the mu RGroove as a promising candidate for large-area and low-material-budget tracking applications.

Fast timing detectors play an important role in high energy physics, medical imaging and other fields. In view of wider applications and potential in the future, new detector technologies need to be investigated. A novel detection concept of fast timing based on the double micro-mesh gaseous structure with a reflective photocathode (FT-DMM) is introduced in light of its good time resolution and long-term operation. A sufficient number of photoelectrons (PEs) and a time resolution of better than 300 picoseconds (ps) for single photoelectron (SPE) are obtained by simulations, suggesting that an overall time resolution better than 100ps is feasible. The FT-DMM prototype was fabricated and tested using ultraviolet (UV) light. The gas gain can reach up to 106, while the measured time resolution of SPE is consistent with the simulated one. Furthermore, a time resolution of approximately 115ps was achieved at an average number of PEs of 5.9, and better time resolution can be expected as more PEs to be generated. These results confirm the good potential of FT-DMM as a fast timing detector for charged particle and UV light detection.

The PICOSEC Micromegas (MM) detector is a precise timing gaseous detector consisting of a Cherenkov radiator combined with a photocathode and a MM amplifying structure. A 100-channel PICOSEC MM prototype with 10 × 10 cm 2 active area equipped with a Cesium Iodide (CsI) photocathode demonstrated a time resolution below σ = 18 ps. The objective of this work is to improve the PICOSEC MM detector robustness aspects, i.e. integration of resistive MM and carbon-based photocathodes, while maintaining good time resolution. The PICOSEC MM prototypes have been tested in laboratory conditions and successfully characterised with 150 GeV/c muon beams at the CERN SPS H4 beam line. The excellent timing performance below σ = 20 ps for an individual pad obtained with the 10 × 10 cm 2 area resistive PICOSEC MM of 20 MΩ/□ showed no significant time resolution degradation as a result of adding a resistive layer. A single-pad prototype equipped with a 12 nm thick Boron Carbide (B 4 C) photocathode presented a time resolution below σ = 35 ps, opening up new possibilities for detectors with robust photocathodes. The results made the concept more suitable for the experiments in need of robust detectors with good time resolution.

In this study, we address the design challenges related to hyperparameters, such as the number of layers and nodes in deep neural networks, by introducing an Improved Genetic Algorithm-based method for optimizing neural network structures (IGA-DNN). We apply this method to the practical problem of β function correction in particle accelerators and develop a storage ring β function correction scheme based on IGA-DNN. We compare our approach with traditional genetic algorithm-optimized neural networks to evaluate its performance. Our results reveal that the neural network optimized by the improved genetic algorithm reduces the number of layers by three and decreases training time by a factor of three, leading to a more efficient model. Moreover, the accuracy of β function simulation correction is enhanced using the IGA-DNN method. This approach can also be extended to optimize other optical parameters and tackle multi-parameter optimization problems, showcasing its versatility and potential for broader applications across various fields.

The PICOSEC Micromegas precise timing detector is based on a Cherenkov radiator coupled to a photocathode operating in a semi-transparent mode and a Micromegas amplification structure. The first proof of concept single-channel prototype was able to achieve a time resolution below 25 ps. One of the crucial aspects in the development of precise timing gaseous detectors applicable in high-energy physics experiments is a modular design that enables large area coverage. The first 19-channel multi-pad prototype with an active area of approximately 10 cm(2) suffered from degraded timing resolution due to the non-uniformity of the preamplification gap thickness. A new 100 cm(2) detector module with 100 channels based on a rigid hybrid ceramic/FR4 Micromegas board for improved drift gap uniformity was developed. Initial measurements with 80 GeV/c muons showed improvements in timing response over the measured pads and a time resolution below 25 ps. More recent measurements with a thinner drift gap detector module and newly developed RF pulse amplifiers show that the pad centre resolution can be enhanced to the level of 17 ps. This work will present the development of the detector from structural simulations, design, and beam test commissioning with a focus on the timing performance of a thinner drift gap detector module in combination with new electronics using an automated timing scan method.

The stability of the beam orbit is essential for a storage ring based light source. An orbit feedback system is usually adopted to help maintain the beam circulating on a reference orbit. The movement and deformation of the Beam Position Monitor (BPM) chambers due to thermal effect can affect the BPM readings. The BPM misreading leads to shift of the reference orbit for the orbit feedback system. The feedback system then corrects the beam to a different closed orbit, resulting in a change in the real beam orbit. Online experiments are carried out to measure the BPM readings dependency on the temperature of BPM chambers in the Hefei Light Source II (HLS-II) storage ring. To improve the beam orbit stability, a compensation system is developed to mitigate the reference orbit shift accordingly. With this compensation system, the stability of the reference orbit is improved to be better than 10 μm in the horizontal plane and 5 μm in the vertical plane. This paper reports our work on the measurement of BPM readings dependency and the development of the reference orbit compensation system for the HLS-II storage ring. The online compensation results are also presented.

In this study, we introduce a new structure of micro-pattern gaseous detector, named proportional counter array (PCa). The standard Printed Circuit Board (PCB) process, which is cost-effective and easy to scale up, is used to manufacture the PCa prototypes. Both simulation and experimental studies were performed to characterise the prototypes, which demonstrated promising performance in terms of gas gain, rate capability, and ion backflow suppression. The prospects of the PCa technology are also discussed.

The ATLAS experiment will replace the present Small Wheel (SW) detector with a New Small Wheel detector (NSW) aiming to improve the performance of muon triggering and precision tracking in the endcap region at the High-Luminosity LHC. Small-strip Thin Gap Chamber (sTGC) is one of the two new detector technologies used in this upgrade. A few custom-designed ASICs are needed for the sTGC detector. We designed an sTGC ASIC interface board to test ASIC-to-ASIC communication and validate the functionality of the entire system. A test platform with the final readout system is set up and the whole sTGC readout chain is demonstrated for the first time. Key parameters in the readout chain are discussed and the results are shown.

The event plane detector (EPD), installed in the Solenoid Tracker at the Relativistic Heavy-Ion Collider located at the Brookhaven National Laboratory, is a plastic scintillator-based device that measures the reaction centrality and event plane in the forward region of the relativistic heavy-ion collisions. We used silicon photomultiplier (SiPM) arrays to detect the photons produced in the scintillator via the fiber connection. Signals from the SiPM arrays were amplified by the front-end electronic (FEE) board and sent to the analog-to-digital converter (ADC) boards for further processing via the receiver (RX) board. The full EPD system consisted of 24 super-sectors (SSs); each SS was equipped with two SiPM boards, two FEE boards and two RX boards, and they corresponded to 744 readout channels. All these boards were mass produced at the University of Science and Technology of China, with dedicated quality assurance (QA) procedures applied to identify any problems before deployment. This article describes the details of the QA method and the related test system. The QA test results are presented along with the discussions.

Application of micro-pattern gaseous detectors (MPGD) to photon detection has been widely investigated over the past decades. A double micro-mesh gaseous structure (DMM) prototype is developed with a thermal bonding technique for this application. Excellent performance for detecting single photon has been demonstrated in various tests with X-ray and ultra-violet (UV) laser light. The gain of the DMM prototype can reach up to >106 for single electrons while maintaining a very low ion-backflow (IBF) ratio down to <0.05%, showing good potential to serve as the photon detector in Cherenkov light detection, as well as for other applications, e.g. TPC readout, where a very low level of IBF is needed. The method to further suppress the IBF of DMM is discussed, and verified by simulation and experimental studies.

To study the picosecond timing technology, a counter with compact structure, fast timing, and relatively low material budget has been developed. The prototype is composed of Cherenkov radiator, micro-channel plate photoelectron multiplier tube (MCP-PMT), and fast readout electronics. The readout electronics consists of a programmable differential amplifier, a multi-threshold differential discriminator, and a timestamp Time-to-Digital converter implemented in a field-programmable gate array (FPGA). The beam test demonstrates that it can achieve an excellent time resolution around 10ps. Its timing performance is also evaluated by a Geant4 simulation framework. The test and simulation result are consistent and there is still potential for improvement.

Diamond-Like Carbon (DLC) is a class of metastable amorphous carbon material that contains both diamond-structure and graphite-structure. DLC provides a new method to produce high-quality resistive materials for Micro-Pattern Gaseous Detectors (MGPDs) owing to its excellent properties, including availability of a wide range of resistivity with good control and good chemical stability. DLC production with magnetron sputtering technique has been studied, and different resistive materials based on DLC coating have been produced and tested in various MPGDs. The surface resistivity of DLC coating can vary from 5 M Omega/sq to 100 G Omega/sq with good control by adjusting the coating thickness and Hydrogen doping. The uniformity of surface resistivity is better than 15% over an area of 15 cm x 15 cm and about 23% over 25 cm x 25 cm. This paper describes the DLC coating technique and characterization of surface resistivity of the coating. A few examples of application of DLC-based resistive materials in MGPDs are also presented. Among them are two types of DLC resistive electrodes with different structures used in micro-Resistive WELL detectors, THGEMs with DLC coating on the dielectric surface to remove the charging-up effect, DLC coated Cherenkov radiators to serve as a radiation-hard photocathode in Picosecond Micromegas detector.

THGEM detectors usually exhibit time-evolution of gain, caused by avalanche charges accumulating on the open insulator surfaces (charging-up effect). Coating resistive layer on the insulator surfaces may help to release the charges to overcome the charging-up effect. Diamond-like carbon (DLC), as a class of amorphous carbon material, can be used as a resistive layer. In this study, thin DLC layers with stable and controllable resistivity were coated on a series of THGEMs by magnetron sputtering technique. A batch of single THGEM detectors was fabricated with these DLC-THGEM films. The gas gain of DLC coated THGEMs (DLC-THGEM) have been tested in detail and compared with normal THGEM. DLC-THGEM with suitable resistivity show very low gain variation versus time and literally no charging-up effect. However, a DLC-THGEM detector shows a gain decrease with increasing irradiation rate. A qualitative theoretical model was built to understand the gain decrease. And the simulation results fit the experimental results well.

The Micro-Resistive WELL (mu RWELL) detector is a novel spark-protected Micro-Pattern Gaseous Detector (MPGD) with a single well-type amplification stage. By integrating a well-type amplification structure with a resistive electrode on a readout board (mu RWELL PCB), the mu RWELL detector is only composed of a cathode PCB and a mu RWELL PCB, resulting in a very simple assembling process without any gluing, stretching, tensioning or other complicated operation commonly practiced in assemblies of other MPGDs. A critical component of the mu RWELL detector is the resistive electrode that is responsible for spark suppression, and hence maintains stable operation of the detector. In this paper, we present a 10 cm x 10 cm mu RWELL detector with two layers readout strips perpendicular to each other. Its resistive electrode is made of a thin coating of Diamond-Like Carbon by magnetron sputtering technique. The gain performance and rate capability of this mu RWELL detector were systematically studied with X-rays, and its detection efficiency and spatial resolution were measured with a test beam. The detector can achieve a spatial resolution better than 70 mu m in both dimensions while the detection efficiency is higher than 90%.