Towards large size pixelized Micromegas for operation beyond 1 MHz/cm2

Abstract

The R&D project being presented aims to improve the use of resistive Micromegas technology in high-energy physics experiments. The project focuses on achieving stable, reliable, and high-gain operation at particle flow rates above 1 MHz/cm2 on large surfaces. To achieve this, the project uses a configuration with small pads readout and requires innovative solutions for the spark protection resistive scheme. Different resistive patterns were investigated, and finally the solution based on a double layer of DLC foils was chosen, demonstrating the capability to perform equally for low and high rates under irradiation of X-rays on the full surface of 25 cm2 of the prototype detectors. With this technology and layout, a detector with an active area of 400 cm2 was recently built. In this work we present the results of high-rate capability, robustness, dependence on the irradiated area, obtained with high intensity X-rays measurements, as well as the results on efficiency and spatial resolution obtained, at low rates, at CERN SPS with high energy particle beams. Additionally, preliminary results of pixelized resistive Micromegas time response are reported. With the successful achievements of this detector and the construction of even larger small-pad resistive Micromegas next year, the project will establish the technology for future use in particle physics and other applications.