### Instruction:

Extract the cause and effect entities from the following sentence:
The trigger threshold is used, at detector element level to discriminate a lightning optical pulse from the background radiance

### Assistant:

VARIABLE: detector element level
CONDITION: to discriminate
CAUSE_1: The trigger threshold is used
EFFECT_1: to discriminate a lightning optical pulse from the background radiance
KEYWORD: at
CAUSE_2: detector element level

