Kouichi Kurosawa

50 nm Hall Sensors for Room Temperature Scanning Hall Probe Microscopy

Bismuth nano-Hall sensors with dimensions ~50 nm × 50 nm were fabricated using a combination of optical lithography and focused ion beam milling. The Hall coefficient, series resistance and optimum magnetic field sensitivity of the sensors were 4×10-4 Ω/G, 9.1 kΩ and 0.8 G/√Hz, respectively. A 50 nm nano-Bi Hall sensor was installed into a room temperature scanning Hall probe microscope and successfully used for directly imaging ferromagnetic domains of low coercivity garnet thin films.

Influence of e-beam aperture angle on CD-SEM measurements for high-aspect ratio structure

The influence of e-beam aperture angle on CD-SEM measurements for a high aspect ratio (HAR) structure was investigated. The Monte-Carlo simulator JMONSEL was used to evaluate the measurement sensitivity to the variation in the bottom CD. The aperture angle of the primary electron greatly influences the measurement accuracy of the bottom CD in the HAR structure. Then, we utilized a technique for energy-angular selective detection to the Monte-Carlo simulation results and found that the measurement sensitivity for the large aperture angle was improved. In addition, the experimental results were qualitatively consistent with the results of the Monte-Carlo simulation. These results indicate that the detection is effective for the bottom CD measurement of a HAR structure.

BWR In-Core Monitor Housing Replacement Under Dry Condition of Reactor Pressure Vessel

A new method of In-Core Monitor Housing replacement has been successfully applied to Tokai Unit 2 (BWR with 1100 MWe) in April of 2001. It was designed to replace a housing under dry condition of reactor pressure vessel (RPV): this enabled the elimination of water filled-up and drained processes during the replacement procedure resulting in the reduction of implementation schedule. To realize the dry condition, the radiation shields were placed in the RPV and the hollow guide pipe (GP) was adopted to transfer the apparatuses from the top to the bottom work area.Copyright