[en] We reported a new device of phantom type compensating filters for pulmonary hilar tomography with polytome U at the 35th annual meeting of the Japanese Society of Radiological Technology. This report is to show application of this compensated method to the head, the hip joint and the lower thoracic spine in tomography. Using the filters optimal density can be obtained in all area of aim part on a X-ray film, and thus makes to get more information. 1) In the head clear shadow of pars nasalis, sinus paranasales and sella turcica is obtained. Destruction or defect of bone contour is easily detected. It is also useful to differentiate the disorders and to determine the expansivity of the lesion. 2) In the hip joint this method has advantages over the ordinary method. There is a few misdiagnosis in trochanteric lesions such as tuberculosis or bone tumor, because of high density at the trochanteric region in ordinary method, but in this method optimal density can be obtained, and misdiagnosis is improved. Soft tissue is sharply visualized, indicating usefulness in diagnosis of existence of hematoma or abscess. 3) In the lower thoracic vertebra it is useful to diagnosis of the thoracic spondylosis, tuberculous spondylitis and compression fracture of the vertebral body, since optimal density of the spine can be obtained. It is also quite useful to detect small ossifications in the vertebral foraman in ossification of the flavum ligament. (author)

[en] A combustion/ion chromatographic method has been studied for the sensitive determination of chlorine in graphite. A graphite sample was burnt at 900degC in a silica reaction tube at an oxygen flow rate of 200 ml/min. Chlorine evolved was absorbed in 20 ml of a 0.1 mM sodium carbonate solution. The solution was evaporated to dryness. The residue was dissolved with a small volume of water. Chlorine in the solution was determined using ion chromatography. The method was applied to JAERI graphite certified reference materials and practical graphite materials. The detection limit was about 0.8 μgCl/g for a 2.0 g sample. The precision was about 2.5% (relative standard deviation) for samples with chlorine content of 70 μg/g level. The method is also usable for coal samples. (author)

[en] Technetium-99 is a long-lived fission product with a half-life of about 2.1 x 10⁵ years, which decays by β-emission. For the transmutation of ⁹⁹Tc, research on solid technetium was started. Technetium metal powder purchased was analyzed by X-ray diffraction, γ-ray spectrometry, and inductively coupled plasma-atomic emission spectrometry and -mass spectrometry. The lattice parameters obtained were agreed with the reported values. The metallic impurity was about 15 ppm, where aluminum and iron contributed mainly. No impurity nuclide with γ-emission was found. Using the technetium metal powder, button-, rod-, and disk-shaped samples of technetium metal were prepared by arc-melting technique. Thermal diffusivity of technetium metal was measured on a disk sample from room temperature to 1173 K by laser flash method. The thermal diffusivity decreased with increasing temperature though it was almost constant above 600 K. (author)

[en] Exhaust ducts 2F and 3F of Research Building No.4 was renewed by replacing old steel ducts lining with vinyl chloride to hard type vinyl chloride ducts. Following the preparation works from July 1997, the construction was started at the beginning of December 1997 and finished at the end of April 1998. Before the construction, a working group consisting of the facility manager, the manager for radiation protection and the representative users of the facility was organized in order to discuss various things concerning the construction such as plans, specifications and so on. All of the management works during construction was done by the working group. In this paper, the renewal of exhaust ducts inside the radiation controlled area (Research Building No.4) is described. (author)

[en] An X-ray spectrometric method has been developed for the determination of ⁴¹Ca in the biological-shield concrete of nuclear reactors. The concrete sample was first decomposed with nitric, hydrofluoric, and perchloric acids. Calcium was then separated from other radionuclides by ion-exchange chromatography and recovered as an oxalate precipitate. X-rays at 3.3 keV from ⁴¹Ca in the calcium oxalate pellet were measured. The detection efficiency of the X-ray measurement at 3.3 keV was calculated from those obtained by measuring ⁵⁵Fe standard pellets at 5.9 keV using mass-absorption coefficients of the calcium oxalate pellet at each X-ray energy. A lower limit of determination of 8 Bq g^-1 was obtained for a sample weight of 1 g. (orig.)