A Novel Two-Dimensional Readout Design for Floating Strip Micromegas Detectors

Abstract

Floating strip Micromegas detectors are high-rate capable particle detectors with excellent spatial and time resolution, allowing single particle tracking with fluxes up to at least 7 MHz/cm2. The amplified ionization charge is collected on copper anode strips kept at a slightly floating electrical potential. The charge signal is coupled to two layers of perpendicular readout strips in x and y, insulated by thin Kapton layers. A complete understanding of the signal formation in the detector, particularly on the orthogonal y-strips, is achieved: simulations disentangle the signal coupling due to alternating weighting field lines with respect to the ion velocity vector and the response of charge sensitive front-end electronics. Different two-dimensional anode designs with optimized strip geometry have been developed based on the simulations. We present the performance of the detector for the different designs measured in 20 MeV proton/neutron and 180 GeV pion/muon beams, using APV25 front-end electronics.