Present status of researches on exo-electron emission and its application for radiation dosimetry are briefly reviewed. After introducing the basic concept of emission center for exo-electron, the charactristic TSEE glow curves of representative exo-sensitive materials such as LiF, CaSO4 and BeO are mentioned with the sample preparations. And the applicability for practical dosimetory is discussed with each materials. Finally, the TSEE properties of anodic film of Ta2O5/Ta heat-treated, its emission center and the mean attenuation length of exo-electron in the film are introduced.
Radiation damage has recently become one of the key problems in nuclear reactor development for the first time in its history started over 30 years ago. The reasons why this problem has become so important will be explained for two crucially important materials, i. e. core structural materials of a fast breeder reactor and first wall materials of a fusion reactor. Advances achieved for about a decade in calculating number of displacements will be reviewed with two topics, cascade simulation calculations and damage energy deposition in multi-component materials, explained in some length. Essential problems arise from heavy exposure of fast neutrons to such an extent that each atom composing crystalline materials suffers displacement from its normal lattice site many times during service life. Change in microstructure by heavy irradiation causes changes in such important bulk properties as ductility, swelling and creep. Considerable parts of the studies of heavy irradiation effects have so far been performed using accelerators. The correlation between accelerator and neutron irradiation effects is discussed in a final section, in which suggestions are made to establish simulation correlations.
This viscometer is composed of two balls of equal diameter and equal mass, which are hung on the two arms of a balance whose ratio of arms LB and LA is ν. The liquid to be measured is put in two vessels, in which the balls are immersed. Each vessel is drawn up with desired constant velocities of υA and υB, such that their ratio becomes υB/υA=n=_??_. By adjusting a counter weight W, hung on the arm at the position of L from the fulcrum, the balance is brought into equilibrium. Let the weight W at υA=υB=0 be W0, the difference ΔW of the weights W0 and W, gives the viscosity η by the equation η=n/1-n•1/6πr•L/LA•ΔWg/υA, assuming Stokes' law of viscosity. Moreover, the viscosity η can be obtained independently of the lifting velocity, provided that the lifting velocity is small. The results of experiments show that the true value of the viscosity is obtainable by direct indication.
A new treatment of the suspension wire in hydrostatic weighing is developed in order to decrease the error which is caused by the instability of the meniscus. The suspension wire is coated by silicone oil, and is heated at a temperature of about 250°C or about 500°C. Two kinds of the suspension wire are then obtained, namely, the one coated at the lower temperature has a repellent surface and the other at the higher temperature has a dampish surface. The repellent surface becomes dampish by thermal oxidization at the high temperature. The repellent wires are comparable to those of platinum black coating hitherto obtained, while the dampish wires satisfactorily show higher reliabilityy to hydrostatic weighings. The standard deviations of the latter wires are several micrograms in case of wires with a diameter of 0. 1 to 0.2mm. and are little different from ordinary weighing in air.