Development of resistive micromegas TPCS for the T2K experiment

摘要

The long baseline neutrino experiment T2K has launched the upgrade project of its near detector ND280, crucial to reduce the systematic uncertainty to less than 4%. An essential component of this upgrade consists of two new High-Angle TPCs (HA-TPCs), for 3D track reconstruction, momentum measurement and particle identification. These TPCs will be equipped with 32 resistive bulk-micromegas modules. The field cage will be realized with laminated composite panels covered with a kapton foil with copper strips for electric field shaping. The 34x42 cm~2 micromegas will use a ~0.5 MΩ/square Diamond-Like Carbon (DLC) foil to spread the charge over the pad plane, each pad being ~1 cm~2. In summer 2018, we have tested a resistive bulk-micromegas prototype on the Harp TPC cage with the CERN/PS beam with excellent results both for the space point resolution and for dE/dx resolution. We report on the design of the HA-TPCs and the preliminary results of the prototype performances with 0.8 GeV/c particles.