Distribution of magnetic flux in the core of a mass spectrometer electromagnet of sector type with a narrow gap, which is used in usual mass spectrometers, was measured under the condition of the flux density lower than about 6000 gauss. The maximum ratio of the magnetic flux density in the core to that of the pole face was about 1.53. The ratios of the magnetic flux in the cores remained nearly constant for the flux density in the pole gap from 250 to 5600 gauss. The ratio of the stray magnetic flux to the magnetic flux passing through the pole piece was about 0.35 in the plane of the pole piece.
An improved instrument to measure or control the magnet field intensity by means of a cathode-ray tube is presented. The principle and the preliminary experiments on the present item were already reported; it is based on the simple fact that the magnet field intensity can be defined uniquely corresponding to the electric field intensity if they are impressed on a cathode-ray beam of constant energy perpendicularly with one another so as to keep the beam in a definite path. In the present work. a cathode-ray tube was specially designed to diminish the influence the stray field of the magnet, and the damping method of the motor-driven part of the electric power supply was improved in order to increase the response speed of the system. The maximum applicable magnet field to the tube was extended to about 35 gauss, while the magnitude of the noise of the system was reduced to about 2 milli-gauss(p-p)in terms of the magnetic field.
The determination of europium in samarium and gadolinium by isotope dilution method is described. This allows a comparatively precise determination of europium without separating it from other rare earth elements.
An attempt was made in order to. develop mass spectrometry to the type analysis of the mixture normal- and iso-paraffins which have only one branch. The present method cannot be applied the type analysis of the mixture in which iso-paraffins have two or more branches.The present analysis consists in making use of the pattern coefficients of parent ions and the summation of them of CnH2n-type ions. The precision in terms of relative error of the analysis is better than10%, and the present method is applicable to the type analysis of the mixtures ranging from C6 to C11 paraffinic hydrocarbons.
Even if the sample had been highly pure substance, various rearrangement peaks were observed the higher mass range than the parent ions. The determination of the small impurity peaks was carried out by examining the linearity of the peak height to the sample pressure. Some metastable peaks which may be caused from decomposition of metastable ions in the magnetic field were also observed.