A new emulsion scintillator used for the liquid scintillation counting has been proposed, and its composition and various characteristics are described. The use of this scintillator enables the measurement with a high counting efficiency and a large figure of merit, not followed by a large amount of ehemilumineseenee, compared with the other emulsion scintillator.
An apparatus applied to α-particle irradiation experiments in dosimetric materials was designed and the performances were tested. The characteristics of the apparatus were as follows. (1) The particle flux density of 102 cm-2⋅s-1 and the energy flux density of 10-3 erg⋅cm-2⋅s-1 were available. (2) The irradiation conditions such as the energy and flux density of α-particles or the irradiation time could be regulated independently of each other. (3) The apparatus could be simply constructed and simply operated, for example, it could be used also in the area other than the radiation controlled area.
The distribution and the origin of 21 elements in fresh waters in the Mikurajima Island were studied. The determination of these elements in stream water and rain water samples collected in the Island were carried out by using the thermal neutron activation method. The results are as follows: In the first place, it was concluded that a great portion of alkali and alkaline-earth elements in stream waters might be driven from sea salt. Meanwhile, the existence of trace elements such as Al, Fe, Mn, Sc, Sm, etc. might be explained by transfer from soil particle in the drainage basin. Furthermore, it seems that trace elements such as As, Co, Cr, Sb, V, W, etc. were supplied from airborne dust by precipitation. In the second place, in general, the contents of Cl, Na, Al and Sc in stream waters in the Island were higher by several times than those in the headwater areas of the Tamagawa river and the Arakawa river in the mainland. On the other hand, the contents of trace elements such as As, Sb, W, etc. in the Island were much lower than these in the mainland.
In our neclear medicine laboratory the quality control (QC) of radioimmunoassay (RIA) has been performed along the line of WHO program for standardization and quality control of RIA. The QC procedure was automated using a minicomputer in order to avoid tedious and time-consurming hand processing. The program was written with BASIC language. The counts of radioactivity measured in autowell counters are recorded in PTR, through which the data are read into a minicomputer (Scintipac 200) . After informations on the concentrations of standards are registered through keyboard of CRT, the data processing is performed including curve fitting, dose calculation and quality control. As the indicators for QC response error relationship (RER), standard curve, precision profile and QC chart are displayed on CRT. On the basis of rejection criteria using these indicators, bad assays are identified to be omitted from reporting. The subroutine installed in the minicomputer system is used for the storage of data on QC samples in each assay, which are used for construction of QC charts. The use of a minicomputer enables implementation of QC of RIA on routine basis with ease and speed.