Feasibility study on a directional detection of WIMP using nano imaging tracker and X-ray microscope

We propose new measurement system for direct detection of WIMPs with directional information using nano imaging tracker (NIT) and X-ray microscope. The NIT made of fine grains of emulsion has a good spatial resolution of several tens nanometer and the X-ray microscope can work as a readout instrument for sub-micron track structure instead of ordinary optical microscope. Wolter type-I fluorescence X-ray microscope utilizing Ag-L line can be applied to this system. Crucial issues are reduction of background event due to random fog and to develop fast selection method of WIMP event candidates.