DETECTIVE QUANTUM EFFICIENCY OF THE 25 MU-M PIXEL SIZE IMAGING PLATE FOR TRANSMISSION ELECTRON-MICROSCOPES

The signal to noise ratio (S/N) and the detective quantum efficiency ( DQE) of the 25 mu m pixel Imaging Plate for transmission electron micr oscopy (TEM) were measured as a function of the number of incident ele ctrons. The S/N increased with increasing the number of incident elect rons, but tended to saturate in high exposure region, although the goo d linearity between the number of incident electrons and image signal was reserved in the region. The DQE at 100 kV and 200 kV had the maxim um values of about 70% and 45% under high gain mode, and about 20% and 10% under low gain mode, respectively. The DQE at 600 kV had the maxi mum value of similar to 30%, while that at 1250 kV had similar to 5%. Comparing the S/N curves with the DQE curves, the optimum electron int ensity regions for high quality TEM images were discussed.