The Design Of Front-end ASIC For Micro-pet System

This thesis discusses an front-end Application Specific Integrated Chip(ASIC) design for the Micro-pet system. Tracing molecules labeled by positron radionuclide which involved in vivo physiological and biochemical process. Through PET (Positron Emission Tomography) process, we may observe physiological and biochemical changes on molecular level. Micro-pet system can detect the two back to back 511KeV gamma-ray generated by positron electron annihilation. Further more, we can deduce particle energy, location and so on. Several key techniques will be discussed in detail.PMT output signals will be processed in the ASIC including amplification, shaping, sampling and holding. The output signal of ASIC will be sent into a data acquisition card which is consisted with flash ADC, FPGA, etc. One of the output of the acquisition card is connected to the matching-circuit. The main task of matching-circuit is to determine whether a pair ofγ-photon is from the same positron emission annihilation. The selected event data will be sent to a computer for further processing and data reconstruction.The major contents of this thesis are as following. The first part will introduce the whole chip design, including the preamplifier design, energy measuring channel design and also the trigger signal channel. The energy measuring design will be elaborated in detail especially the slow shaper design. In the second part we will focuse on the layout design including the placement of individual building blocks and the design of DAC cell. Chip testing methods will be discussed in the final part of the thesis.Test results show that the chip is working properly and has already met all the design requirements.