Spatial Distribution Measurement of High Energy Particle using Time-Of-Flight Neutral Particle Energy Analyzer in Large Helical Device

The time-of-flight neutral particle measurement system1 has been installed on the 10-O port at the 2nd campaign. It has the capability of two-dimensional measurement with a larger viewing angle by using the pivot on the rectangular port, which is set inside of the 10-O mother port. The movable stage with the vertical scan mechanism rotates on the fan shaped stainless rails around the pivot. The sight lines of −2 to 32 degrees against the 10-O port surface makes the angle between the sight line and the magnetic axis of the standard configuration (3.6 m) of 95 to 35 in the 4th campaign. Therefore the analyzer can observe high-energy particles with these pitch angles. The higher scan speed of 0.17 degree/second than that in the last campaign (0.05 degree/s) can be obtained in this campaign. Precise spatial distribution of the high-energy particles can be expected because it enables the continuous scanning in the long discharge.