| 摘要 |
PURPOSE:To reduce the number of parts, especially A/D converters for use, and a cost by controlling the timing of data input to an A/D converter in time series by using a delay circuit. CONSTITUTION:A plurality of photomultiplier tubes (PMT) 3 are arranged on the back surface of a scintillator 1 and inputted with scintillation light. A plurality of the PMTs 3 are sequentially divided to a suitable number and, for every group thus obtained, an A/D converter 7 is arranged via a multiplexer 6. Digital data collected thereby are processed in a digital processing circuit 10 and a position calculation is conducted. The outputs of the PMTs 3 are added to one another in an adder 11 via corresponding preamplifiers 4 and inputted to a timing generating circuit 12. The delay time of a delay circuit 5 is controlled by a timing signal from the circuit 12. A sequence is selected by the multiplexer 6 and A/D-converted 7. An obtained digital signal is inputted to an held by a register 9 corresponding to the PMT 3 via a register 8 and the position calculation is conducted through a digital processing in the circuit 10.
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