Tagger Time Resolution

The Tagger Microscope is expected to have a time resolution of 200 ps or better. This specification imposes a strict demand on the light pulse rise time uncertainty because it introduces trigger time uncertainty when Constant Fraction Trigger (CFT) point is used.

Scintillation Pulse Time Resolution

The scintillations in the fiber are distributed exponentially with a characteristic decay time $\tau$ = 2.7  for BCF-10/20. Since the variance is $\tau ^{2}$ (and is additive over independent events) the time uncertainty for N generated photons becomes $\tau /N^{1/2}$. Thus, in order of priority, this relation implies

1. scintillating fiber with smallest decay time must be procured
2. photon capture and detection efficiency must be optimized