A 20 cm, 90° direction focussing mass spectrometer was constructed for laboratory use in isotope geochemistry. The mass spectrometer is of conventional design but has a greater flexibility for future modifications. For obtaining high vacuum of better quality and for its easy maintenance, a 40 l/s getter ion pump was employed in the main pumping system together with a chemisorption pump. Without using an oil diffusion pump, vacuum of better than 10^-8mm Hg was easily obtained, although argon background was always high as expected. The absolute amount of the residual argon in the analyzer tube was found to range from 1 to 10 × 10^-7ml STP.
The mass spectrometer was used for the high sensitivity mass spectrometry of rare gases using a six-stage secondary electron multiplier. It was demonstrated that the system has a enough sensitivity to measure 10^-9ml STP xenon. The residual gases in the analyzer up to xenon mass regions were also analyzed.

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The half-life of ¹³⁰Te double β-decay was determined by a mass-spectrometric method. The samples were old tellurium ores (such as tetradymite: Bi₂Te₂S), obtained from Oya gold mine in Japan. The amount of ¹³⁰Xe, which was occluded in the tellurium ores as the daughter of ¹³⁰Te double β-decay, was measured by isotope dilution method using ¹²⁸Xe as a spike. The mass spectrometer used is 20 cm radius, 90° single focusing type. The detection limit for xenon under static operation is about 10⁵-10⁶ atoms by using a 12-stages Cu-Be electron multiplier followed by a vibrating reed electrometer as a measuring system of ion currents. Th spike ¹²⁸Xe used was prepared by neutron irradiation of KI in a nuclear reactor. The amount of four samples used were 17.5g (33.8% Te), 10.9g (13.2% Te), 22.3g (22.4% Te) and 12.4g (22.4% Te) .
The decay products: ¹³⁰Xe, occluded in tellurium ores, were extracted by heating them in an electric furnace at about 700-1200 °C. Pure calcium metal, titanium-filament, tangsten-filament and a dry ice trap were used to remove impurity gas components. In the mass spectra, excesses of ¹²⁹Xe, ¹³⁰Xe and ¹³¹Xe over normal xenon were found, and the excess of ¹³⁰Xe was predominant among them. The excess amount of ¹³⁰Xe obtained were(2.09±0.27) × 10^-11 ccSTP, (1.01±0.18) × 10^-11 ccSTP, (2.65±0.08) × 10^-11 ccSTP and(1.27±0.06) × 10^-11 ccSTP for above each sample, respectively. On the assumption that the ¹³⁰Xe excesses obtained above were entirely due to the ¹³⁰Te doubleβ-decay, the half-lives of ¹³⁰ Te doubleβ-decay were calculated to be10.7 × 10²⁰ years, 5.38 × 10²⁰ years, 7.29 × 10²⁰ years and 8.27 × 10²⁰ years for the above each case. The half-life of ¹³⁰Te double β-decay is(7.91±1.11) × 10²⁰ years on the average. This value agrees fairly with the result(1.4×10²¹ years)of Inghram-Reynolds, the result(3.3×10²¹ years)of Hayden-Inghram and the theoretical value(2×10^21±2 years)of Primakoff-Rosen, based on two neutrino theory. The xenon age of the tellurium ores, which was used for calculation of the above half-lives, was determined from the age of porphyrite, of which the age is expected to be about the same as that of the tellurium ores. The age of porphyrite was determined to be(9.06±0.29)×10⁷ years by K-Ar method with the same mass spectrometer as used for the above ¹³⁰Xe measurement.
The ratio of ¹²⁹Xe excess to ¹³¹Xe excess is obtained about 1.6, and the ratio, estimated from the neutron absorption cross sections for¹²⁸Te and¹³⁰Te and their abundance ratios, is about 0.6. These ratios are not in agreement one another. So these excesses in ¹²⁹Xe and ¹³¹Xe seem to be produced, in part, by neutron absorptions of ¹²⁸Te and¹³⁰Te and, in part, by different processes.

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The rate of exchange of lithium isotopes ⁷Li and ⁶Li ocurring between lithium chloride and lithium chloride-1, 4-dioxane complex has been studied in 1, 4-dioxane solution at 100°C.
The rate constant was calculated from the time dependence of the isotope abundance ⁷Li/⁶Li in the complex with the other informations obtained in the preliminary experiments. The apparatus used for the determination of ⁷Li/⁶Li is a sector type mass spectrometer with a surface ionization ion source of the triple-filament type.
The value of the second order reaction rate constant was found to be(1.99±0.13)×10^-2 l·mole^-1·sec^-1, which is comparable with the rate constants of other similar exchange reactions of metal complexes.

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Isotopic techniques involving ¹⁸O have been used to study of the reactions of potassium superoxide with water vapour and carbon dioxide. The isotopic analyses have been carried out with an analytical mass spectrometer. For the reactions of potassium superoxide with water vapour and with mixture of water vapour and carbon dioxide, tracer experiments prove that all of the oxygen gas liberated by these reactions originated from potassium superoxide. Carbon dioxide did not react with potassium superoxide without water vapour at room temperature.

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The isotopic ratios of lead, thorium, and uranium in minerals were determined by vacuum spark mass spectrography. The facts that no chemical separations were necessary, that size of minerals for analysis were very small, and that the isotopes of interest were examined in situ were advantages of this procedure. Preliminary dating by 207Pb/206Pb, 238U/206Pb, 235U/207Pb, and 232Th/208Pb by this method agreed well. The sources of discrepancies were discussed.

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The present investigation was undertaken to see if a practical method could be worked out for analysing the high boiling range naphthenic acids by the mass spectrometry. From the study, following method is recommended for the analysis of naphthenic acids:
The acids are converted into hydrocarbons by reduction via the alcohols (R·COOH→R·CH₂OH→R·CH₃) . The resulting hydrocarbons are separated into the saturated fraction and the aromatic fraction by liquid chromatography, and the latter is analysed by the mass spectrometer to determine the compound types and the carbon number distribution.
The saturated fraction is further converted into the aromatic hydrocarbons by dehydrogenation reaction with platinum black. The dehydrogenation product is separated into the saturates and the aromatics by chromatography. The sum of the five membered ring, gem-type and straight chain carboxylic acids is estimated from the weight of the saturates, and the compound types and the carbon number distribution of the six membered ring carboxylic acids are determined from the mass spectrometric data of the aromatic fraction.
Furthermore, the acids are converted into their acid anilides, which are measurable by the low energy ionization method. The compound types and the carbon number distribution of the five membered ring and the six membered gem-type carboxylic acids are also determined from both the data of the six membered ring analysis of the dehydrogenated product and the data of the analysis of the acid anilides. The carbon number distribution of the straight chain carboxylic acids are also known from the analysis of the acid anilides.

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