At Tsugu mine in Aichi Prefecture, antimony was mined and smelted until 1956. The amounts of antimony present in the soil
of the abandoned mine were measured to enable us to detect any traces of the operation of the mine and to measure the level
of environmental contamination with antimony. The quantity of antimony in rings of hinoki and sugi was also measured to obtain
information about chronological changes in environmental conditions. The quantity of antimony in the samples was determined
by INAA. The antimony concentrations in eight soil samples at different points in the Tsugu mine area were 8–17,000 ppm.
We have constructed a new system which could analyze a position distribution of several elements in a sample with 2 dimensional
prompt γ-ray analysis (2D PGA) system using focused neutron beam at JAEA. We aimed that the system could analyze local information
in a sample with a good signal γ-ray from interested elements to noise of background γ-ray ratio. As a result, this system
could determine the position resolution and spatial resolution within 1 mm.
A positron lifetime study has been done on dielectric multilayer cavity mirrors for free-electron-laser experiments by the use of a variable-energy pulsed positron beam. A long-lived ortho-positronium component has been observed at low positron energy region, corresponding to the depth of the top amorphous SiO2 layer. The intensity of the positronium component correlates with the degradation and restoration of the mirrors. We discuss the relation between the positronium intensity and degradation mechanism of the mirrors. The present studies revealed that the slow positron lifetime technique is highly sensitive to the properties of the mirrors and is useful for the evaluation of the mirrors.
In-beam Mössbauer spectra of 57Fe, decayed from short-lived 57Mn (T1/2 = 1.45 min) implanted into potassium permanganate, KMnO4, were measured at temperatures between 11 K and 130 K. This is the first application of a secondary RI beam to the study of valence states after nuclear transformation. The in-beam Mössbauer spectra obtained below 90 K could be analyzed with two components, a doublet and a singlet. From the calculations of the molecular orbital wave functions, the singlet is suggested to be substitutional 57Fe atoms for Mn-sites in tetrahedral [MnO4]– with an unusually high valence state of Fe8+.