Nondestructive inspection of patterns formed on inner surfaces of small diameter pipes
Inspection of patterns formed on inner surfaces of copper pipes with a small diameter of 2 mm was investigated. At first, space patterns with widths of 20-30 μm were lithographically formed using a handmade laser-scan exposure system. The exposure system was equipped with a monitoring system of a laser beam spot irradiated on the inner surface of pipe for the exposure. Pattern inspection was executed utilizing this monitoring system. In the case of exposure for patterning, the beam monitor was used for confirming the position and size of the laser beam. However, being prevented by the bright beam spot, background views were not clearly observed. For this reason, the pinhole that is initially inserted for reshaping the laser beam and making an appropriately small spot was removed, and the brightness of the beam spot was mitigated. In addition, inspected camera images were stored as video images in a personal computer using a video capture. As samples for the inspection, space patterns in resist films and groove patterns etched in copper pipes were used. As a result, resist space patterns were observed quite clearly, and pattern widths were measurable. In addition, the measured pattern widths almost agreed with the ones measured using a scanning electron microscope after cutting a half of the pipe off. On the other hand, etched groove patterns were not so clear as resist patterns. However, it was clarified that fatal pattern defects such as kinks, shifts, and breaks were detected, if the pattern images stored in the computer were carefully investigated. The new nondestructive inspection method is effective.
Arbitrary Patterning onto Inner Surfaces of Small-Diameter Pipes Using Laser Scan Lithography
Arbitrary patterning onto inner surfaces of fine pipes with an inner diameter of 2 mm was investigated. A handmade exposure system was used as the patterning tool, and the specimen pipes were moved for relatively scanning the laser light-beam with a wavelength of 408 nm. At first, character patterns with a height of approximately 200 μm were delineated. Although several element patterns stuck out of the jointed patterns, all the delineated characters were legible, and the pattern widths were almost homogeneous except the parts where other element patterns were closely delineated. Next, arrays of V-shape patterns were delineated. Measured width fluctuation was approximately ±5 μm for the average width of 44 μm. Finally, the resolution limit or the the pattern-pitch limit of dense line-and-space patterns was investigated. As a result, the minimum pattern pitch was 29 μm, and the finest continuous resist pattern with a width of 6 μm was obtained. It was verified that arbitrary patterns were certainly delineated onto the inner surfaces of the fine pipes.
A technique for large-field, superficial electron therapy.
The application of electron beams to radiation therapy has received increased attention in recent years. This interest stems largely from the special characteristics of the electron depth-dose distribution; the fall-off in depth dose near the end of the range of the electrons is particularly rapid for electron beams having energies less than about 10 Mev. Such an electron beam is suitable for the treatment of widespread, superficial lesions, where it is desirable to minimize the dose to deep tissues. All the common sources of super-voltage x-rays, apart from radioactive substances, are inherently capable of producing an external beam of electrons, though with varying degrees of complexity. Electrons of about the energy suitable for superficial therapy (several Mev) may be used to produce an x-ray beam which is sufficiently penetrating for the treatment of even the deepest lesions. The Stanford medical linear accelerator was designed to provide both x-rays and electron beams. The accelerator and its applic...