Deposition fractions of aerosol particles in straight pipes widely used in routine air sampling were measured and compared. The experiment was made by using the monodisperse uranine methyleneblue particles with diameter of 4.2μm and geometric standard deviation of 1.1. Results are summarized as follows. The deposition characteristics of aerosol particles in a straight pipe are nearly the same independent of material of the pipe. In the laminar region the estimation of the deposition fractions can be made using the equation for a smooth pipe independent of the roughness of the inside wall of the pipe. In the turbulent region, however, the deposition is strongly affected by the wall roughness. The estimation of the deposition fractions in the pipe with the rough wall for the turbulent region can be made by using the friction factor corresponding to the roughness of the pipe. The flow velocity of the minimum deposition fraction for particles with diameter of 3-5μm is in the vicinity of 500cm/sec.
A thermoluminescence dosimeter has been used practically for personal monitoring of X-γ rays in our institute over two years. In this report, the dosimeter instrumentations are briefly outlined and the procedures to obtain a reliable estimation for each personal dose are mainly discussed. The results obtained are summarized and some of them are compared with those obtained by film badges. It was effective for accurate estimation to use the correction factors determined for individual elements. Careful treatments as described in this paper are necessary to perform the personal monitoring with an accuracy of 1 mrem per 2 weeks.