Current dosimetry with solid-, liquid and gas-state dosimeters for high intensity X and gamma radiations is reviewed with a particular concern aboutthe ionization method, for which detailed discussions are given from the view-points of ion recombinations (in three cases of soft X-ray, cobalt gamma ray and pulsed shape ionizations), stem effects (radiation induced current, in insu-latorand secondary electron emission), character change of ionizing gas, temperature effects and high energy effects by quoting the author's experimental results andopinions. To explain mathe-matically the establishment of electronic equilibrium, an approximate expression for specific ioni-zation of electrons along their path is introduced. The concept of the dose of radiation is also discussed in detail and a proposal is made to revise the definition of Exposure.
The resolving characteristics of an X-ray image intensifier tube is a composite of characteris-tics of input target, electron lens and output fluorescent screen that constitute the tube. The output distributions of these constituents when subjected to narrow linear X-rays, electron source and electron rays are measured independently. They all are found nearly Gaussian with their half widths of about 0.50_??_0.55mm, 20_??_30μ and 25_??_30μ respectively. When the output distribution by a line energy source is assumed to be Gaussian, the response function obtained by Fourier conversion is of Gaussian distribution as well. Thus the response function of an image intensifier can easily be obtained as a product of response functions of the three constituents. From the above measured values, the estimated distribution was Gaussian of 6.5 line pairs/cm in nominal cutoff spatial frequency. The spatial frequency response, which was calculated fromoutput res-ponses obtained by imposing X-ray images of various wire patterns to input target, was close to the value calculated from output distributions of theconstituents.
With a combination of capillary method for measuring viscosity and drop-weight method for measuring surface tension and with a single capillary, viscosity and surface tension of liquids are simultaneously determined. The capillary and a liquid reservoir connected to the top of the capil-lary with a constantflow head device are placed in a thermostat and the rate of flow is controlled. For determination of viscosity, drops that require shorter time to form, and fordetermination of surface tension, drops that require longer time to form, are collected separately and by weighing them the mass of flow per unit time and the mass per drop are obtained. With nineteen capil-laries of different dimensions, measurements. are made on several sorts of pure liquids and aqueous solutions of glyceline. Variations of viscosity and surface tension of water with temperatureare also examined. The obtained results are in good agreement with the values given in authentic tables.
A Xenon arc lamp image furnace combined with an adequate floating zone apparatus has been, designed and successfully applied to zone melting of ironand alumina. Experiments are carried out to evaluate the stability of the moltenzone of the above substances. The results showed that the arc image furnace worked quite satisfactorily as demonstrated through the measurement of distribution coefficient for copper in iron and of surface tension of alumina at its melting point. This is attributable to the fact that a Xenon arc is more stable than a carbon arc as the radiation source. The details of operation and performance characteristics of this furnace are described.
A Mylar window type liquid hydrogen target has been devised for experiments with an INS electron synchrotron. A commercial Dewar vessel is used as the reservoir of liquid hydrogen and glass fiber “superinsulation” asthe thermal shield. The loss rate of liquid hydrogen is about 0.1 liter per hourwith no liquid nitrogen cooling and no high vacuum insulation.
Dynamical properties of surface tension of some liquids are studied experimentally. After a liquid is sucked up into a long glass capillary, the lower end which is kept just to touch the liquid surface, the liquid column is let free to fall. As the process may be treated as quasi-stationary, the term of inertia in the equation of motion of liquid column can be neglected and we get the :following relation between the falling velocity (v) and the length (l) of the liquid column, _??_ where, γ is the radius of capillary, θ the inclination of capillary to a vertical line, g the acceleration of gravity, ρ the density of liquid, η the coefficient of viscosity, σ the surface tension, and α the contact angle. From the linear relation between v and 1/l, η and σ cos α are determined. With the decreaseof flow velocity, the value of σ cos α decreases and the value of η tends to increase.