Development of Multichannel High Time Resolution Data Acquisition System for TOT-ASIC

We developed a multichannel high time resolution data acquisition (DAQ) system for time-over-threshold (TOT) application specific integrated circuit (ASIC). The developed field-programmable gate array-based DAQ is composed of 144 channels per board with an Ethernet readout to measure energy and timing information simultaneously. The measured time precision of the developed DAQ board was reduced to 62.5 ps. The proposed DAQ with TOT-ASIC can potentially be used for several radiation detection applications, such as positron emission tomography (PET) and Compton imaging. The DAQ board is applied to PET and named PET readout board with a high-speed network (PETNET). In the first version developed, the PETNET had a time precision of 1 ns by implementing a double data rate method. This demonstrates that this method is useful for capturing electron-positron pairs of
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Na using two PETNETs. We obtained 2-D cross-sectional images placing two 8 ×8 detectors facing each other. In the second version developed, the PETNET had a time precision of 125 or 62.5 ps by implementing a delay-line method. Cable length measurements proved that PETNET has a position resolution of 4.5 cm at the speed of light. To synchronize the time of data on several PETNETs, a time-of-flight method was adopted, and all the data were compared with each other with accurate time precision.