Occupancy "lifetime" factor

Hartmut Sadrozinski

If you look at extra hits, either from noise or extra particles, they will be
uniformly distributed in time. That means their rate will depend on the
"life-time" of the electronics. In the new CAFE-M /ABC, where we edge trigger,
the lifetime is 25ns bucket  width. In the present CAFE/CDP, where we level
trigger, the output width is about 70ns, i.e. and the numberr of time buckets
ot life time is 2.5. I.e. for random occupancy, the numbere for ATLAS opreratio
n will be 2.5 smaller than we measure now. By the way, the correction factor
for the LBICn is 0.6 and for the LBICp is 2.5 too.

I hope this helps. Note that the factor does not apply to correlated "noise"
like next neighbor hits etc, so they have to be subtracted carefully.