Development of x-ray optical system for scan-type all-sky monitor

We have developed one-dimensional X-ray optics for the kind of scan-type detector like the Gas Slit Camera (GSC) onboard MAXI. GSC consists of gas proportional counters with slat collimators and has the sensitivity of order of 10 mCrab by an orbit (92 min) scan. Aiming to detect more fainter sources such as afterglows of gamma ray bursts and electromagnetic counterparts of gravitational wave events than the sensitivity, we investigate a scan camera with one-dimensional X-ray optics. By mounting one-dimensional X-ray optics in place of slat collimators on slit and sensor, the sensor receives more focused photons with small size without decreasing total field of view during an orbital period. We have developed X-ray tracing simulations of the optics by Geant4 including X-ray total reflection process with a goal of detection sensitivity to 1 mCrab/orbit.We fabricated the test model of flat mirror optics of conical approximation of Wolter-I which was designed based on the simulation, and the performed the measurement of X-ray image of the model at ISAS 30 m X-ray beam-line. We will report on the design of X-ray optics, the simulation by Geant4, and the results X-ray experiment.