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electronics [2013/12/10 20:17]
pereira [Trigger Box] |
electronics [2013/12/10 20:19]
pereira [Trigger Box] |
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| ==== Trigger Box ==== | ==== Trigger Box ==== |
| | As explained above, the trigger logic is implemented in a LeCroy 2367 ULM by means of its XC4000E Xilinx FPGA. The schematics of the firmware can be found [[here]]. |
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| In addition to the singles and coincidence triggers, two separate trigger sources labeled "External 1" and "External 2" can be used. The various sources can be selected from the trigger box to define the raw trigger, which is then sent to a third AND gate for computer busy rejection. The busy latch (on the middle) is set by the raw trigger after a 50 ns delay, and prevents subsequent events to be accepted. It is reset by the computer once the current event has been processed. The live trigger signal feeds several gate generators which provide appropriate gates for the ADCs, QDCs, TDCs and an eventual coincidence register. Note that the trigger box contains its own coincidence register for which the input signals are delayed by 50 ns, and the gate width is set by the coincidence gate generator. The request event signal is latched before being sent to the computer. | In addition to the singles and coincidence triggers, two separate trigger sources labeled "External 1" and "External 2" can be used. The various sources can be selected from the trigger box to define the raw trigger, which is then sent to a third AND gate for computer busy rejection. The busy latch (on the middle) is set by the raw trigger after a 50 ns delay, and prevents subsequent events to be accepted. It is reset by the computer once the current event has been processed. The live trigger signal feeds several gate generators which provide appropriate gates for the ADCs, QDCs, TDCs and an eventual coincidence register. Note that the trigger box contains its own coincidence register for which the input signals are delayed by 50 ns, and the gate width is set by the coincidence gate generator. The request event signal is latched before being sent to the computer. |
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