Research Of Electron-traps And Foil Intensifying Screen Upon Gamma-ray Imaging Plate For Industrial Nondestructive Detection

In the 80^th, Fuji-Film Corporation invented the Imaging Plate (IP) for commercial use. IP has many merits over the traditional fluorescent film for its lower exposure dosage, richer grayness, easier digitalization and repeatable use. IP had been widely acknowledged and had gradually prevailed in medical fields in the end of last century.Clear and low exposure dosage radiography is not only the need of medical fields but also of the industrial non-destructive detection. The traditional fluorescent film now used in the non-destructive detection cannot satisfy the need of modern radiography requests for its low image quality, long detection time and serous pollution problems. Imaging plate, especially used for the purpose of detecting thick work pieces, can obviously reduce the exposure duration and enhance the image quality for its excellent properties.How to obtain clearer image by lower exposure dosage was emphasized in this paper. The feasibility of applying of IP in industrial non-destructive detection was firstly studied and the foil intensifying screen and F-centers were mainly focused on. The main works are listed as follows:1. Newly developed phosphor was made to Imaging Plate and clear X-ray andγ-ray images were obtained, which is the first time in domestic country. Themain merits and barriers of IP were also discussed in its way of industrial appliance.2. Foil intensifying manner used on films was studied to intensify IP. No such work has been done before.3. Intensifying coefficients of several fore- intensifying foils were measured. The relationship between the thickness of the foils and the photo-stimulated luminescence intensity was studied. Quantitative calculation of the secondary radiation on imaging plate after adding the foil was made by the interaction theories of the matter and radiation.4. The effect of back-intensifying foil on the PSL was studied, and the effect of back-screen on the imaging quality of the imaging plate was also discussed. The main factor of reducing the quality of image was sure to be the characteristic X-ray of the surroundings but not the back-scattering radiations.5. The effect of electron traps on the radiation storage and the PSL intensity was systematically studied. The theory that the PSL of high valent cations doped electron traps is always higher than the lower valent cations doped ones was put forth for the first time. It is also the first time to propose that the doped high valent cation impurities might be a factor of PSL enhancement of IP.