Gunji Shinoda

Frequency Response of Semicircular Magnetic Spectroscope

The performance of a semicircular magnetic spectrograph and spectrometer has been studied from the point of view of the Fourier-analysis. The approximate expression for the intensity distribution of the image is given and the spatial frequency response has been calculated as in the field of lens optics. The applications of the theory are described for (i) determination of the optimum condition of experiments (ii) evaluation of the performance of spectroscope (iii) estimation of the input spectrum through the output and for (iv) measuring intervals for discrete recording. The approach described here may be useful for the comparison of performance of various different types of magnetic spectroscopes and may give the first step to introduce information theory into the problem of magnetic spectroscopy.

Mechanism of Precipitation of α from β in 60:40 Brass

Body-centred cubic β brass, containing ca. 40% Zn, obtained by quenching from 850°∼900°C. shows reversal process of Kurdjumow and Sachs type transformation during tempering. Various intermediate structures between β and face-centred cubic α were ascertained by means of X-ray analysis using capillary and ordinary X-ray tubes. Such are body-centred and face-centred tetragonal structures having various axial ratios; therefore the transformation must take, place with gradual manner, although the formation of martenstic needles are well known. The decrease of solubility of Zn in a solid solution due to lowering of the temperature, determined from X-ray data, is more significant than of Konobejewski.

The Soft X-ray Spectroscopy of the Solid State by the Electronic Differentiating Method : Aluminium L3

A method was developed of observing soft X-ray emission spectra directly on the screen of a cathode-ray oscilloscope. Soft X-rays emitted from metals were detected by a photoelectric device which works under retarding voltages having saw-tooth wave form. The photoelectric current was differentiated three times by electronic differentiating circuits. The saw-tooth wave voltage corresponds to the reciprocal of wavelength, while the differentiated photoelectric current represents the intensity of soft X-ray emission. Using this method we obtained the emission spectra in about 1/100 sec, exposure without serious contamination of the anticathode. As an example, the structure of the L 3 emission spectrum of Al was studied.

Improved Counting Rate Meter for X-Ray Measurement

A new type instrument for measurement of X-ray intensity with a G-M counter is described. The advantages of this counting rate meter are as follows; (1) statistical fractional standard deviations are constant throughout whole range of 1:10 4 , (2) probable errors are also made constant by means of logarithmic scale, (3) the time required for reading is shorter in higher counting rate, and (4) therefore it is benefit-able to measure the counting rate from natural counting to saturate counting with probable error less than 3% using 0.8% accuracy meter and with only one scale.

Lattice Defect Research by Kossel Technique and Deformation Analysis

An electron probe microanalyzer (EPMA) was applied for the deformation analysis of aluminum single crystals. The lattice distortions caused by tensile stresses were observed by Kossel patterns, which are sensitive in their change of shape to lattice distortion. The effects of lattice distortion would appear as splitting, tearing, bending, broadening, disappearance, and shift of Kossel lines. This distortion behavior can be analyzed successfully. The inhomogeneities and anisotropy appearing on every line were explained by the crystallographic consideration of slip mechanisms. The lattice distortions and corresponding changes in Kossel patterns depend on the direction of elongation; the deformation modes of those crystals which show typical fcc behavior in stress—strain curves can be reasonably explained by a fragmentation model. It was also found that there are some portions in Kossel patterns where some specific Kossel lines, i.e., {200} and {111}, are very sensitive to lattice deformation.

STUDY ON CORROSION OF AUSTENITIC STAINLESS STEEL BY URANYL SALT SOLUTION

Applying surface radioactivity measurement, an autoradiographic method, and a weight-loss method, the corrosion resistance of some austenitic Cr--Ni steels against uranyl salt solution has been investigated. It was concluded that the count number and the autoradiographic method are useful to study the initial stage of corrosion mechanism. An x-ray diffractometer study was also made on welded specimens to examine the carbide precipitation and the ferrite formation, and the Nb carbide precipitated in the matrix was easily detected by in x-ray diffractometer study. The relative abundance of Nb carbide is less in the welded portion than in the other portion of base metal, and in the welded specimens there is no ferrite phase. Niobiumstabilized steels always show good corrosion resistance against uranyl salt solution. Some of the specimens were neutron- irradiated (10/sup 12/ cm/sup 2//sec, 8 Mev) at about room temperature, and the irridiated specimens showed no change in the structure and the corrosion characteristics. (auth)