Upgrade of the level 1 global trigger system in the Belle experiment

In this paper, we describe design and development of the new global decision logic units for the Belle detector at the KEK B-factory. The new units consist of two identical 9U VME modules which are designed using the programmable logic techniques. Each module has an inexpensive programmable logic device that has high density input and output lines. Performance tests of these new modules and existing system are compared and showed good results. Utilizing the nature of the logic device on the board, we also examine possibility of the implementation of an artificial neural network algorithm to the new trigger board for a more efficient data acquisition. Index Terms--Artificial neural network, FPGA, Level 1 trigger.