Light trigger scheme in larndsim

[YifanC]

Larnd-sim is designed for DUNE ND-LAr and its prototypes. The basic detector designs are similar. However, different trigger logic may affect how the simulation is carried out.

Here I list the possibilities for light triggering that I can think of.

• Trigger type:
  A. external signal (beam, laser etc.)
  B. threshold on ADC sum from all light readout channels in the detector
  C. threshold on ADC sum from all light readout channels in a module
  D. threshold on ADC sum from all light readout channels in a TPC
  E. threshold on ADC sum from all light readout channels in a light detector (two channels for LCM and six channels for ArCLight)
  F. threshold on ADC from a single light readout channel
• Trigger range:
  1. all light readout channels in the entire detector
  2. all light readout channels in a single module
  3. all light readout channels in a single TPC
  4. single light detector (two channels for LCM and six channels for ArCLight)
  5. single light readout channel
• Trigger forwarding scheme:
  i. one pacman in each relevant TPC
  ii. one pacman in each relevant module
  iii. one pacman from any in the detector
  iv. all pacman('s) in the relevant TPC
  v. all pacmans in the relevant module
  vi. all pacmans in the detector

Trigger range 1., 2.,3., 4. may collapse if the detector is single cube or single module. Similar note applies to the trigger forwarding scheme. Trigger range and trigger forwarding scheme indicate the individuality of the light readout trigger and light trigger marks in the charge readout system. Although some of the combination may never be realised and some may yield redundancy because of the detector configuration (rather than the trigger design), there are still many different scenarios.

Currently, following the 2x2 design, we have LIGHT_TRIG_MODE = 0 to cover B.1.iii. and LIGHT_TRIG_MODE = 1 to cover A.1.iii.. Although LIGHT_TRIG_MODE = 0 urgently needs some work!

In addition, here's a brief summary of trigger scheme in the existing and planned prototype:

• Single cube: usually they have no light detectors, and even if they have some, it will likely be covered by B.1.iii. and A.1.iii. (if ever) which have already been implemented. If there is plan to have B.5.iii, then larnd-sim needs to be adapted.
• Single 2x2 module: we have Module 0123 and Module X operated under B.1.iii.??? B.1.vi.??? 0.C.iv(most probably)??? B.3.v.??? (B.4.iv.??? B.5.iv.??? I don't think so, as I vaguely remember it's triggered on sum ADC of the LCM's?)
• 2x2: the trigger scheme is designed to be 0.A.iii. and 1.A.iii.
• Single ND-LAr module (FSD): it is not fully determined how the trigger will work on FSD, but it may be similar to what was applied on the single 2x2 modules, but will depend on the development of the electronics and DAQ.
• ND-LAr: the trigger logic is not settled and will depend on the electronics and DAQ. It may be A.3.iv. and B.3.iv.

After all, we should definitely work on

• fixing LIGHT_TRIG_MODE = 0
• accommodating all trigger schemes in the existing detector designs.