| 摘要 |
PROBLEM TO BE SOLVED: To efficiently remove residual charge and to shorten the cycle for obtaining one sheet of an X-ray image signal by fluoroscopy and photography by obtaining the appropriate cycle range of AC electric field. SOLUTION: Generally, processing for removing the charge remaining in a photoconductive layer 57 is started immediately after obtaining one sheet of the X-ray image signal. The residual charge is removed in a state where the inside of the layer 57 is set to be the AC electric field by impressing the AC electric field on a photographic panel 12 from a power source part 28. When it is assumed that a value corresponding to time necessary for the charge to pass the layer 57 is (t), the cycle A (second) of the AC electric field is selected to satisfy an expression:τ×5<=A<=t×2×10<3> . In the expression t=L/(μ×E),μis the mobility of the charge and a larger one between an electron and a hole is used (cm<2>×V<-1>×second<-1> ), L is the thickness (cm) of the photoconductive layer and E is the intensity (V×cm<-1> ) of the electric field. Thus, the residual charge is efficiently removed.
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