| 摘要 |
PURPOSE:To improve counting-rate characteristic and position operating accuracy and to make it possible to prevent the deterioration of an image by dividing the period into three or more stages in time for every pulse signal, performing integration, and converting the integrated value for two or more stages for beginning half part into the estimated value. CONSTITUTION:The combination of three or more sets of photoelectric converters, linear amplifiers, A/D converters and digital integrators is provided. The light from a scintillator is converted into the pulse signal. The pulse signal is linearly amplified. The digital position signal is obtained from the amplified pulse signal. In each integrator, an input digital signal Zd undergoes integration operation in an adder 61 and respective registers 62-64 during the respective periods. A plurality of the registers 62-64 are selected during the respective periods, which are divided into three or more stages in time from the rise-up with a multiplexer 65. At the normal time, the integrated values are added in an adder 68, and the integrated output INTZ is outputted. When the pile-up occurs, a value, which is stored in a conversion table memory 66 as an estimated value, is added to the sum of the values in the registers 62 and 63.
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