What are the Trigger inputs?
This covers the NIM module configuration which processes the signals that go into the "E bits" of the trigger. More info will be filled in later giving a description of each channel that is input into the trigger.
Summary of external triggers
Beam trigger: "1D" and "1F" from detector IRM. Triggers on front edge of "1F". This is rediscriminated to form a 150ns wide pulse plugged into the "E1" external input to the trigger memory card. Another much narrower beam trigger pulse is plugged into crate 13, channel 1549, for timing.
Strobe trigger: The frequency of the strobe square wave is 2.01 Hz. This is rediscriminated to form a 150ns wide NIM pulse plugged into the E2 input to the trigger. A narrower pulse is plugged into crate 13, channel 1550.
Calibration triggers: There are actually 4 calibration triggers that all use the E3 input. The trigger software can tell how long the pulse is by the number of times that input bit (e.g. E3) is set high at 100ns intervals. We use this fact to assert different types of triggers into the same NIM input. Cube triggers are given 150ns wide input, and are asserted 1 or 2 times into the trigger memory. Laser triggers are given a 450ns pulse, which asserts 4 or 5 times. We skip 3 because if the cube-double fires, it is less likely to look like a laser trigger. A four-plane coincidence of the tracker plus a cube is given a NIM pulse width of 650ns, which asserts 6 or 7 times. The special laser trigger which fires when the booster sends beam, but not to MiniBooNE is given a NIM pulse width of 850ns, which asserts 8 or 9 times in trigger memory.
The remaining triggers originate from internal inputs, the DET & VETO comparators which detect the number of main/veto tubes that fire in a 200ns time window.
Available documentation on the NIM modules used to process all of the trigger input signals.