Study of Negative-Ion TPC Using μ-PIC for Directional Dark Matter Search

Negative-ion time projection chambers(TPCs) have been studied for low-rate and high-resolution applications such as dark matter search experiments. Recently, a full volume fiducialization in a self-triggering TPC was realized. This innovative technology demonstrated a significant reduction in the background with MWPC-TPCs. We studied negative-ion TPC using the μ-PIC+GEM system and obtained sufficient gas gain with CS_2gas and SF_6 gas at low pressures. We expect an improvement in detector sensitivity and angular resolution with better electronics.