Author/Authors :
Kِhne، نويسنده , , J.K and Fent، نويسنده , , J and Frِchtenicht، نويسنده , , W and Gaede، نويسنده , , F and Gruber، نويسنده , , A and Haberer، نويسنده , , W and Kiesling، نويسنده , , C and Kobler، نويسنده , , Manuela and Mِck، نويسنده , , J and Wegner، نويسنده , , A and Goldner، نويسنده , , D and Krنmerkنmper، نويسنده , , T and Kolander، نويسنده , , M and Kolanoski، نويسنده , , H، نويسنده ,
Abstract :
Since 1996 the H1 experiment is fully equipped with two independent fast pattern recognition systems operating as second level triggers (L2). The decision time is 20 μs. One of the two is the neural network trigger. It runs an array of presently ten VME-boards with CNAPS 1064 chips (20 MHz, 128 Mcps) by Adaptive Solutions. The input trigger data from the detector components arrive in various formats on a 8 × 16 bit wide 10 MHz bus. Before usable as 8-bit input values to the CNAPS they are preprocessed by several bit-manipulating algorithms and arithmetic functions implemented on XILINX 4008 field programmable gate arrays (FPGA). The startup strategy for the new system is to concentrate on photoproduction channels or low multiplicity final states which so far could only be efficiently triggered with unacceptable high rates.
