TABLE II.

Trigger schemes, corresponding logical subpixel connections and average number of photons required to generate a timestamp. The last column is the average number of photons required to trigger the pixel due to cumulative trigger probability, assuming photons are evenly irradiated on a pixel (data from dSiPM user manual).

Trigger scheme	Logic connection	Average number of photons to trigger
1	sp1 ∨ sp2 ∨ sp3 ∨ sp4	1
	(sp1 ∨ sp2) ∧ (sp3 ∨ sp4)
2	∨	2.33
	(sp1 ∨ sp4) ∧ (sp2 ∨ sp3)a
3	(sp1 ∨ sp2) ∧ (sp3 ∨ sp4)	3.0
4	sp1 ∧ sp2 ∧ sp3 ∧ sp4	8.33

^a“∧” represents the AND logic while “∨” represents OR logic. sp1 here represents subpixel 1 and so on.