Reducing IBF with a novel MPGD structure using a bulked mesh on a GEM

Due to their construction simplicity and accuracy for reconstructing particle trajectories, Micromegas (mesh-GAseous Structure) and Gas Electron Multiplier (GEM) detectors are commonly used as readout systems in Time Projection Chambers (TPCs). The main limitation of these two types of detectors is the ion backflow, which may result in space charge in the TPC. We present a new Micro-Pattern Gaseous Detector (MPGD) structure, which combines a mesh and a set made of a GEM surmounted by a mesh at only a few hundreds μm above. We report the performance results of two prototypes using this new structure. We show that this new detector is capable of reducing the ion backflow to less than 0.2% for a total gain of around 2000.