1970 Volume 19 Issue 11 Pages 489-500
Autoradiography using radioisotopes is one of the most useful toots for metatturgy ana other material research. Since microautoradiographic techniques, however, have not yet been fully established, a cooperative research on microautoradiography has been carried out by Subcommittee on Autoradio graph, the Physical Sciences and Industry Committee of Japan Radioisotope Association, mainly in order to investigate problems of the resolution, using various methods of sample preparation and experimental operation.
Test samples were prepared by alternately laminating radioactive 110mAg and nonradioactive Ag layers and rolling them at high or low temperatures. The attained thickness of each layer was between 17 μ and 2.5μ.
By using these samples, the resolution of microautoradiography in contact, stripping and dipping methods was studied, and also influences of sample thickness, separating layer thickness, pressure on photographic emulsion and humidity during exposure upon the resolution were examined in detail.
Distribution curves of blackening density obtained with several factors affecting autoradiograph of the test sample were theoretically calculated by means of numerical integration. The modulation transfer functions were also obtained from these curves.
The results obtained are summarized as follows:
1) The silver sample prepared by the above method is quite suitable for testing the resolution in microautoradiography.
2) Appropriate pressure must be applied on the emulsion layer for obtaining high resolution in the contact method.
3) The limit of resolving power in the stripping method was obtained when the layer thickness was about 5 μ.
4) As the influence of separating layer upon the resolution is remarkable, it is necessary to choose suitable materials and thickness of separating layer.
5) It is desired to keep the humidity between 30% and 40% during the exposure.
6) The modulation transfer function obtained from the experimental results agreed well with that calculated theoretically.
