A general description is presented of detectors which are mainly employed in the high energy experiments. We discuss their performance from the point of view of two-dimensional, position detectors. The detectors described are the ones whose operations are connected with gaseous discharge. The position sensitive solid-state detectors are described briefly. The discussion is also presented on the mechanism of gaseous discharges.
New methods for measuring sound velocity are described. Photo-electric detection of the first order spectrum in the double diffraction of a laser beam by two successive ultrasonic waves makes it possible to generate a light beat at a difference frequency of the two ultrasonic waves. From a theoretical discussion of the phase of this light beat three measurements of sound velocity are predicted. That is a comparison of two sound velocities one of which is known, the absolute measurement of the velocity in a small limited volume in the medium, and the instantaneous value of the velocity which changes with time. These methods are confirmed experimentally using an NaCl solution. A change in sound velocity down to 0.05ms-1 can be detected when it is varying with time.
The Maker fringe method has been employed to determine the magnitude of the nonlinear optical susceptibility accurately in ferroelectric NaNO2 as well as the relative sign in NaNO2 and Ca2Sr(CH3CH2CO2)b, both by rotating a plane-paralleled sample and by sliding a slightly wedge-shaped one. An analysis of the Maker fringe in nonabsorbing biaxial crystals has also been made, including corrections of the birefringence effect. As a result, we have obtained d31=0.23±0.02, d32=5.2±0.7, d33=0.30±0.02, d15=0.23±0.02 and d24=5.2±0.7 in NaNO2 relative to d11 in quartz for a fundamental wavelength 1.06μm, and d31•d33<0, d32•d33>0, d24•d33>0 in NaNO2 and d31•d33<0 in Ca2Sr(CH3CH2CO2)6. Further, the domain effect, the experimental errors and a comparison of the sliding method with the rotating method are discussed.
This paper describes a method of obtaining experimental evidence on the existence of an interfacial layer in Si Schottky barriers. It is shown that capacitance-voltage and photoresponse measurements on metal-Si Schottky barriers can be utilized to investigate the properties of a metal-Si interface. By applying this method to Au-Si Schottky barriers, it becomes evident that the interfacial layer in Au-Si system is a thin SiO2 film with a thickness of about 10Å. This method is applicable to metal-SiO2-Si structures with an oxide thickness less than 20Å and Si donor concentrations between 1×1015 and 5×1016/cm3. Brief discussions are given on the donor concentration dependence of the barrier height and the current transport mechanism of Au-Si Schottky barriers.
This paper describes the digital image restoration of atmospherically degraded images. By using the computer simulation technique, the influences upon the image restoration of the decision error of the parameter determining the point spread function due to air-turbulence and of the gradient of the H-D curve of the film used to record the degraded image have been investigated. The final results clearly prove the usefulness and advantage of the method of least squares in handling atmospherically degraded images.