| 摘要 |
PURPOSE:To increase an S/N ratio and obtain high resolution by utilizing a wide dynamic range effectively by providing a gain varying circuit which varies the gain of the output of a photoelectron multiplier tube (PMT), an adding circuit which obtains an energy signal by adding the output of the PMT, and a control circuit which controls the gain of the gain varying circuit according to the energy signal obtained from the adding circuit. CONSTITUTION:Many PMTs 2 are arrayed on the back surface of a scintillator 1 and coupled optically with one another, and their outputs are sent to adding circuits 3-5, whose outputs are sent to dividing circuits 14 and 15 through integration circuits 11-13 to calculates X/Z and Y/Z, so that position signals X and Y are outputted through sample holding circuits 16 and 17. Then, programmable amplifiers 7-9 are interposed between the adding circuits 3-5 and integration circuits 11-13. Then the adding circuit 6 adds the output of the PMT2. The control circuit 10 controls the gains of the programmable amplifiers 7-9 according to the output of the adding circuit 6.
|
