The. BESIII Trigger Fast Control System Developed

The thesis describes the Research and Devolopment work of the Trigger Fast Control System (FCS) of Beijing Spectrometer III (BESIII), which is being built as one part of the Beijing Electron Positron Collider II (BEPCII) upgrade project. The BEPCII and BESIII will be completed in 2007 and continue contributing to the tau-Charm physics studies after BEPC and BESII.The Fast Control System is an important part of Trigger System, and is also a key part of BESIII.It is the backbone of Data Acquire System, Trigger System and the Front-End electroncs (FEE) of subdetectors for collecting useful event data.The FCS is designed for meeting the actual needs of BESIII and based on advanced and new electroncal technologies. The Fast Control System (or Timing,Trigger and Control System) of other spectrometers like BaBar, Cleo III, Belle and LHC have been studied for reference in design of the one of BESIII.High-speed Serial optical fiber transmission technology will be used to transfer fast control signals between the detector FEEs and the FCS, and it may be used in other parts of BESIII. This technology has the advantages of cutting off the ground loops between the systems, improving the system immunity to electro-magnetic interference and lengthening the transfer distance. Some important aspects of this technology are carefully studied, such as the bit-error-rate, error report ,synchronization recovery, latency skew of channels and phase stability. After research and test, scheme for link self-synchronizing recovery is given, which makes the system more robust. The lantency skew is as large as half a period, and the approach to minimize it is to adjust the front edge of the sampling clock falling at the middle of the stable half period of all deserialized data in the receiver side. Estimation and some beam testing for radiation effects on optical fiber link in hard radiation condition have been made. Some tests in using Agilent 103xA as Serializer/Deserializer have been made.The FCS of BESIII will send trigger pass and control signals such as L1, CHK to and receive read-out state signals such as FULL, REER from FEEs and trigger subsystems. It also receives 41.65MHz system clock and fans it out. FCS is composed of Clock Fan-out Board, Fast Control Board, Fast Control Daughter Board, Fast Control Signal Fan-out Board, Trigger Readout Control Board based on VME bus.