Camera trigger logic - Majority

The simulation of the majority trigger logic is defined as follows:

1. The discriminator input signal from each pixel (or sum of multiple pixels in the case of super pixels) is compared to the , taking into account channel-to-channel variations .

2. The time and signal sum above the thresholds are calculated and compared to values defined by the parameters and , taking into account the corresponding channel-to-channel variations for these parameters.

3. The signal at the output of the discriminator is generated based on the following parameters: , , , and .

4. The majority logic, defined in the , is then applied and can be either of the following options:

   1. SmartPixel logic: e.g. a pixel cluster of 7 pixels where the central pixel must have fired (would be a line in the like “Trigger * of 561 562 597 +598 599 633 634”, with the smart pixel indicated by the ‘+’).

   2. A majority trigger of a number of pixels (or super pixels) inside a group of pixels (or super pixels). The list of pixels composing the super pixel and the trigger group must be defined explicitly in the camera config file, e.g., “MajorityTrigger * of 0[1,32,33] 64[65,96,97] 2[3,34,35] 66[67,98,99]”, where 0[1,32,33] indicates one of the super pixels and 0, 64, 2 and 66 indicate the pixel group. A * for the number of pixels required for a trigger means that it will be replaced by the per-telescope default, configured with the parameter.

5. A minimum time or signal sum over threshold for each sector is required for a trigger, with the thresholds defined by and respectively.

6. an optional current limit can be applied with , excluding any pixels from the trigger if they exceed a certain current, calculated as, $\(\begin{aligned} \textrm{DC} =& \, \num{1e+9} \times \hyperref[par:nightsky-background]{\textbf{nightsky\_background}} \times\textrm{RandGauss}(1, \hyperref[par:gain-variation]{\textbf{gain\_variation}}) \\ & \times \hyperref[par:pm-average-gain]{\textbf{pm\_average\_gain}} \times \hyperref[par:adjust-gain]{\textbf{adjust\_gain}} \times \num{1.609e-19} \times \num{1e6} \, .\end{aligned}\)$ The used for the DC current is the same as used for the single-p.e. amplitudes (while that part in gain differences resulting from QE differences, compensated through HV adjustment for uniform flatfield, cancels out here). The parameter also applies for the discriminator input signal and all FADC channels (and also the per-pixel random value resulting from ).

7. For a single telescope trigger, a minimum number of super pixels is required, , based on a coincidence of the discriminator outputs.