A Long lived radio-nuclide ⁴⁰K and stable nuclides of calcium produced by cosmic ray in iron meteorites were determined by mass spectrometry using surface ionization technique with an electron multiplier. These nuclides were extracted simultaneously in a systematic wet chemical separation scheme with other stable nuclides of titanium, vanadium and chromium and long lived nuclide ⁵³Mn. For the determination of absolute contents of the products, the dilution method was apllied using spikes, ³⁹K and ⁴²Ca. The contamination level of natural potassium and calcium was reduced as low as possible; the lowest, we obtained, was 0.2ppm potassium and 0.4ppm calcium. In such sample, the enrichment of ⁴²Ca, ⁴³Ca, ⁴⁴Ca and ⁴⁶Ca due to cosmic-ray products were observed at 70, 200, 20 and 200% respectively. It was not always possible to reach such low contamination level. On the other hand, the most of ⁴⁰K extracted from iron meteorites was found to be the cosmic-ray products even at a higher contamination level. For the isotope fractionation and the isotope discrimination problem, long lived ⁴⁰K seems not to be affected seriously because of the very high ratio of cosmic-ray product to natural ⁴⁰K and of being placed between two stable nuclides of potassium. When we got the lowest contamination, cosmic-ray-produced ⁴¹K should be detected at the about 5% enrichment in mass 41 peak. However, we have no mean to correct the isotope fractionation and discrimination of potassium and could not determine the ⁴¹K in this work. According to the spallation systematics and also our earlier works, fortunately, ⁴⁰Ca and ⁴⁸Ca are produced by negligible amounts by cosmic-ray irradiation. The isotope fractionation and discrimination in the mass spectrometry were corrected by normalizing ⁴⁰Ca and ⁴⁸Ca peaks in samples to their reference values which were selected from literatures and our data of reagent calcium. When sample size was very small, mass 42 and 43 peaks were usually disturbed by tenacious hydrocarbon peaks. In order to eliminate such disturbances, the cavity of ion source in mass spectrometer and the filament had to be baked before the measurement in each run. Examples of results are as follows[unit: 10¹³atom/g of meteorite]. ⁴⁰K: Grant A-350, 0.526, Grant Q-260. 0.541, Grant E-240, 0.470, Grant I-110, 0.42, Grant I-55, 0.458, Aroos, 0.715, Treysa, 0.546. ⁴³Ca: Grant A-350, 1.77, Grant Q-260, 1.6, Grant I-110, 1.6, Grant I-55, 1.42, Aroos, 2.29, Treysa, 1.55. A dependency on the depth in the meteorite Grant was found to be about 20%, smoothly decreased from the surface to the center for both ⁴⁰K and calcium. Our samples were not enough in number to determine the preatomospheric size of the meteorite yet. A fine structure in a cumulative spallation yield curve was examined in the isotopic ratios of cosmic-ray-produced calcium analyzed in a highly enriched sample. The yields of ⁴²Ca and ⁴⁴Ca were 10±5% higher than an expected yield of ⁴³Ca. When we borrow the data by H. Voshage, the yield of ⁴¹K was also found to be apparently lower. Experimental procedures, especially the chemical procedure and the mass spectrometry of very small amount of these elements are described in detail.

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The concentration of cosmic-ray-produced stable nuclides of titanium and vanadium in iron meteorites, especially in the Grant meteorite, were determined by a surface ionization solid source mass spectrometer using an electron multiplier. A triple filament technique was applied for both elements. A rhenium ribbon was applied to the center(ionizing)filament and for titanium two tantalum ribbons and for vanadium tungsten ribbons to the side(sample)filaments respectively. Repeated experiments using 0.1-1 microgram quantity of reagent titanium and vanadium indicated a satisfactorily high reproducibility throughout the cource of this work. The results with the reagent titanium and vanadium were in a good agreement with the determinations by Hogg and by White et al respectively. Using about one gram of the iron meteorites specimen, the extractions of titanium and vanadium were performed simultaneously in a systematic wet chemical separation scheme with potassium, calcium, chromium, and manganese. For the determination of the absolute contents of cosmogenic nuclides, isotopic dilution analysis was made using enriched ⁴⁶Ti for titanium and reagent vanadium for vanadium as the spikes. The determination of above nuclides were possible with sufficiently low contamination of natural elements at the levels of 0.1 ppm for titanium and 0.01 ppm for vanadium. The enrichment in ⁴⁹Ti was observed most prominently in the mass spectrum of titanium samples separated from the iron meteorites. At the same time the other products, ⁴⁷Ti and ⁴⁶Ti were also determined with a high reproducibility. ⁵⁰Ti was also measurable though the error, ±30%, was still high. Examples of the data of cosmic ray produced stable titanium and vanadium are as follows;[unit:×10¹³ atoms/g. of meteorite]Aroos: ⁴⁶Ti 4.00, ⁴⁷Ti 4.85, ⁴⁹Ti 7.70, ⁵⁰Ti 0.27, and ⁵⁰V 5.45. We have completed a set of data at A=50which includes new data of ⁵⁰Ti and ⁵⁰V, and our previous data of ⁵⁰Cr and also ⁵⁰V.The distribution of these three isobars provides useful measure in the spallation systematics in meteorites. Two parameters, R and S, in the semi-empirical equation of spallation cross section, Inσ(Z)=-R(Z-SA)²+K, were calculated to be 1.5±0.2 and 0.469±0.001 respectively. The radiation age of Aroos was estimated applying widely ranged pairs of both radioactive and stable nuclides, which were now all available. Each age derived from different isobaric pairs agreed well and this may suggest the negligible effect of space erosion or similar mechanisms such as many small collisions in space. In Grant, the depth effect was found to be effectively negligible with ⁴⁹Ti and ⁵⁰V in contrast to lighter nuclides such as Ne and K. Any irregurality in a curve of spallation yield vs.ΔA was not observed in mass range of 46-49. The experimental procedure is described in detail.

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Electron biprism technique, if extended to any charged particles, will make comparison possible among two-beam interference fringes of electrons and other particles under the same(including wave length)geometrical condition. Combination of the technique with sharply focusing mass spectroscopy will realize such experiments. Due to the tradition since Young-Fresnel, it is believed that two-beam visibilities of particles of various masses under the same geometrical setup are constant and independent of each total sum of macroscopically separated path-lengths, which is not to be confused with ordinary path-difference.(See Fig. 2.)But the assumption of such constant visibility has never been verified experimentally and seems to become gradually unnatural as the masses increase. Experimental reexamination of the assumption is proposed with method of observing an expected mass effect on interdependence between visibility and pathlengths. The smaller visibilities are expected for the heavier masses and the longer path-lengths, contrary to conventional constant visibility; e.g., ≅0.4 for protons of wave length 0.02Å and beam width0.2μ in a realizable experimental setup. Technical problems for the experiment and effects to the observation theory are discussed.

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A Langmuir method has been used to determine the vapor pressure and the heats of vaporization of strontium atoms from strontium oxide applied on tungsten and rhenium surfaces. The data obtained are log P_atm=5.064-2.071×10⁴/T and l^To=4.11±0.14eV for tungsten, and log P_atm=6.095-2.496×10⁴/T and l^To=4.95±0.14eV for rhenium, respectively. By measuring the ion current of ⁸⁸Sr⁺ with a mass spectrometer the values of the heats of vaporization of strontium ions have also been obtained as l^T+=7.07±0.08eV and l^T+=6.73±0.07eV for tungsten and rhenium, respectively, under the assumption that the ion vaporization processes may be described by the, Saha-Langmuir equation. The work functions of the surfaces applied with strontium oxide have been discussed.

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Time variation of the emission of both positive ions and neutral particles was simultaneously examined with one-and two-component systems of alkali-metal iodides on a platinum wire heated to 1080°C. A “suppression effect” was observed: - by the presence of the heavier alkali-metal iodide, MHI, (1)the emission pattern of the lighter alkali-metal ion, ML⁺, was much changed, (2)the integrated emission current of ML⁺ was reduced to 40-60%, and(3)the reduction of ML⁺ emission current was accompanied by an increase in ML emission in the form of neutral particles by 20-30%, while the MH⁺ emission was not affected by the presence of WLI. Discussion on a mechanism of this effect is given from three view-points of the work function change, charge transfer, and recombination reaction. The conclusion is that the suppression effect is due to the recombination of ML⁺ and I^- on the filament surface enhanced by the presence of M_HI.

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A high sensitivity mass spectrometer with very low background was constructed for quantitative determinations of extremely small amounts of gas isotopes. The improvement of the ion source was carried out in order to reduce the background ions originating in the ion source itself. The ions desorbed from the electrode surface of the ion source by electron bombardment were found to give a large fraction of the background ions at pressures below 10^-9 Torr. The peak heights of these surface ions, e. g., H⁺, F⁺ and Cl⁺ changed with the geometrical structure and the operating condition of the ion source in a remarkably different way compared with the residual gas ions. The surface ions could be distinguished through their distinct feature of the dependence of their peak heights on the repeller voltage, and their reduction was accomplished by the improvement of the structure of the ionization chamber.

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A vacuum ultraviolet monochromator and a quadrupole mass spectrometer have been combined with the differential pumping systems, since hydrogen, helium and argon gases were used as the carrier gas for the photon source. The photoionization efficiency curves were observed by the hydrogen many-line spectrum. The photoionization efficiency curves for the parent and the fragment ions of (CH3)2 CO have been measured with the photon band width of 0.9Å. For the parent ion, autoionization for super-excited states was first observed in the threshold region of the photoionization.

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A large high resolution mass spectrometer has been constructed for the analysis of organic compounds. This apparatus is of a modified type of Nier-Johnson double focusing mass spectrometer. The dimensions for the ion trajectory were chosen as follows: central radius, deflecting angle and magnification of the electrostatic field are ae=500mm, φe=70°. and Me=0.555, and those in the magnetic field am=400mm, φ=70°, Mm=1.06, respectively. Therefore, the theoretical resolving power of this instrument is 71, 700 with the slit widths of the source and the collector are 0.005mm and 0.0028mm respectively. Step voltages of 9, 600, 7, 200, 4, 800, 3, 600 and 1, 800 V for ion acceleration were so established as to have respective mass ranges of M/e up to 450, 600, 900, 1200 and 1800. A new bright ion source having two dimensional parallel plate lens system was developed for this instrument. And, a secondary electron multiplier with a gain of 10⁶ was used to measure the ion currents. A maximum resolution was obtained with a mixture sample of xenon and tetrachlo roethylene. The ¹³¹Xe-C₂³⁵CI₂³⁷CI doublet with the mass difference of 1.47 mu at M/e 131 was separately recorded with a 10% valley, so that the resolving power of this instrument estimated with this doublet is approximately, 89, 100 with definition of 10% valley separation using an collector slit about 0.001mm. In this case, the source slit width was estimated about 0.003mm, then theoretical resolving power corresponds to 148, 000. As the other experimental result, metastable transition processes of molecules have been studied using precursor spectral method. Preliminary investigations of n-butane and iso-butane revealed a number of transitions not previously reported, in addition to a high intensity for several known transitions.

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After completely destroying the old large mass spectrograph by the high-tide typhoon in 1961, the reconstruction of a new large instrument, which has the quite similar dimensions in the main parts to the old one's, was planned. The machinery works of the main parts was finished in 1964, and their setting up works was begun in 1964 in the new building of our Science Faculty. The newly constructed large machine has the following points improved against the old one: in order to have better focus stabilities, the effective areas of the electric field and the main magnetic field are both somewhat extended; for eliminating charging up effect on the slit blades as much as possible, the blades can be baked. With the new machine, electric method can be used together with photographic method simultaneously, for measuring double mass differences. And, we call the new machine“the large double focusing mass-spectroscope”. The preliminary focus adjustment was carried out with photographic method. In this case, even in the best condition, the resolution obtained was only about 100, 000 or somewhat less, and in most cases it was only the half or one third of the above best valve. In order to find out this cause, the electric method was adopted. And as the results, the rather large a. c. stray magnetic field, filling in the room which affected the ion beam oscillation, was found. At present, as the results of eliminating such these stray magnetic field as much as possible, the half-width resolution of about 300, 000 has been obtained with the widths of main and collector slits of about 10μ Erespectively. In order to increase the absolute accuracy of doublet mass difference measurements, some preliminary experiments with electric method have been carried out. A few results obtained so far will be described in this report.

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Performance test of the electrical deflection type mass. spectrometer, being proposed in our previous paper, was carried out. Four stage type test tube showed the resolving power of about 6. On the other hand, if we assume an idealized deflection field and a well-focussed monochromatic ion beam, the resolving power of the tube is estimated to about 60. The discrepancy between theory and experiment is mainly caused by the following factors. 1. Fringing effect of the condenser field (a)weakening of the deflection field in boundary regions between adjacent condensers. (b)existense of the electric field component in the direction of tube axis which varies ion's axial velocity which must be constant. 2. Directional distribution of the ion beam. 3. Transit time of the rf deflection voltage, at the instant of phase inversion. The effect of the other factors, such as the energy distribution of beam ions which due to the ion source character, the constructional exactness of the electrode system, etc, was found to be sufficiently small in the present stage of experiment.

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