add dead-time information

[KrisThielemans]

Suggestion after Data Elements meeting 29Nov2024:

Introduce new type of time-block with
i. Singles dead-time fraction encoded as 2D array (det_element, energy window)
ii. optional coincidence dead-time fraction encoded as 2D array (module1, module2)

Note that this needs a start/end time in each time block

[KrisThielemans]

Actually, I think this needs to be formulated as "alive-time": the alive-time fraction (i.e. "detection probability") is computed as the product of the probabilities that both detectors are "alive" times the module-pair records coincidences (it is an "and" relation).

Example: suppose 2 detectors are only alive half the time, then the coincidence will be only alive a quarter of the time.

[KrisThielemans]

Note that this needs a start/end time in each time block

We have a type for this already

PETSIRD/model/TimeFrameInformation.yml

Lines 2 to 5 in eb60569

	TimeInterval: !record
	fields:
	start: uint # Type could maybe be RelativeTime in the future
	stop: uint