Toshimasa Tomoda

A new system for real-time synthetic aperture ultrasonic imaging

The authors devised a way to generate in real time a cross-sectional image of an object with uniformly high resolution based on the synthetic aperture focusing technique (SAFT). A computer simulation was conducted to study the effects of essential parameters on the resulting images. An imaging system was built that produces a cross-sectional image composed of an assembly of line images of depth direction, i.e. processed A-scan images, and displays a scroll picture on a CRT (cathode ray tube) with no interruption regardless of the object size. It takes only 3 ms from the start of transmission of the ultrasonic wave to the completion of a line image reconstruction, and the framed image on a CRT is updated at the TV rate of 1/30 s. Imaging experiments were conducted using the system, and its expected performance was demonstrated.<<ETX>>

An In-Process X-Ray Measuring System with a Heat-Resistant Filter Transmitting Soft X-Rays for Light Elements

We constructed a RHEED-Si (Li) SSD measuring system which has the capability to detect, in-process, characteristic X-rays emitted from light elements such as oxygen. The feature of the system is that the X-ray detecting system uses a heat-resistant filter made of an Al film and a BN film in front of the SSD. The filter transmits soft X-rays and blocks light and heat radiation which emanate from processes and influence the SSD performance. It was demonstrated that the measuring system could detect change in the O-Kα X-ray intensity from a SiO2/Si(100) sample when it was heated to and kept at 500°C.