High granularity resistive Micromegas for tracking detectors in future experiments

Abstract After exploring different solutions and testing several options, the high granularity resistive Micromegas technology is now mature enough to offer an efficient operation up to particle rates of 10 MHz/cm2, maintaining the gas amplification above 104, with a large margin before breakdown in order to ensure a stable and reliable operation. The detector exploits small-size readout pads for occupancy reduction and a double Diamond-Like Carbon (DLC) resistive layer with a network of dot-connections to ground for a fast charge evacuation. The double-layer allows preserving the minimum resistance to suppress the discharge intensity for stable operations. The performance measured with particle beams at CERN have shown a spatial resolution below 100 μm for mm-wide readout pads and a few ns time resolution. Now, the technology is being scaled to larger areas, with the construction of detectors with an active area of ∼20×20 cm2 (already achieved) and new ∼40×50 cm2 prototypes under construction. An overview of the detector technology, including the latest results, is presented in terms of the gain and rate capability (measured in the laboratory) and efficiency, time and spatial resolution (measured at the CERN SPS). Possible applications in HEP experiments, as well as future developments, are also reported.