Design of Optical Fiber Link for In-beam PET

To monitor the irradiation dose and position of heavy ion beam with the imaging methods in the treatment of the heavy ion tumor radiotherapy, an In-Beam Positron Emission Tomography(In-beam PET) will be mounted in Heavy-Ion Medical Machine(HIMM) in China. In In-beam PET, the event data is collected by the detector array and digitized by front-end Data Acquisition Units(DAQU). Then digitized data will be sent to the Central Processing Module (CPM) through the optical fiber link, and finally transmitted to the host sever via the PCIe interface. A single DAQU can obtain a maximum data rate of 2.2 Gbit/s, which imposes high requirements on the transmission bandwidth of the optical fiber link accordingly. As the core of DAQU is Cyclone V FPGA and the core of CPM is Kintex-7 FPGA, the realization of reliable real-time communication between FPGAs of different companies is a challenge. This paper presents a new design and the implementation of the optical fiber link for In-beam PET, aiming to realize the stable communication between Cyclone V FPGA and Kintex-7 FPGA. The performance of the design shows that it can meet the demand of high stability and high accuracy in real-time.