Development of negative-ion gaseous TPC using micro pattern readout for direction-sensitive dark matter search

Abstract

NEWAGE is the experiment of direction-sensitive dark matter search using low pressure gaseous TPC with micro pattern strip readout (μ-PIC). It allows to measure the distribution of angles of WIMP-nuclear recoil by track reconstruction, and it allows a positive signature of dark matter. In recent years, large size (∼1 m3) TPC filled with SF6 gas, which is so called “negative-ion gas”, is under development. A TPC with negative ions is a novel technology for the measurement of absolute position of drift direction coordinates in a self-triggering system. The determination of the absolute track position allows to discriminate nuclear recoils in the target gas volume from alpha-rays from the detector surface, which is one of the background sources. Furthermore, diffusion of drifting negative ions is expected to be lower than that of nominal electron drift, which allows to improve angular resolution. This presentation reports the status of the development of negative-ion gaseous TPC with a prototype small chamber. In addition, we started to develop O(100) μm pitch gaseous TPC detector with pixel type readout system to achieve reconstruction of short track nuclear recoils with good angular resolution. It enables to explore lower mass region of direction-sensitive dark matter searches. We also report about the status of the pixel detector development.