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Trigger efficiency
Dear all,
in order to study trigger performances for BHABHA selection,
we have performed an analysis on runs with a minimum bias
trigger ORfino*ORfone (736000 events only GTS and TOF detectors
selected). Therefore checks have been made on TDCs hits and
pattern units (PU) bits.
To study HYP selection a bigger volume of data is necessary.
Keep in mind that trigger works on MeanTimer (MT) signals,
then to evaluate the efficiency of the trigger modules
it's relevant the comparison with software selection made using
MT signals. On the contrary to evaluate the global efficiency
(which contains inefficiency due to other causes, for instance
problems on MT modules) the comparison has to be made using
TDC hits. So this is the reason because the second way to calculate
efficiency leads to worse values.
First results are the following.
Efficiency for trigger BTB1-3 (extended BTB with only 2 hits on Tofino)
BTB 1-3 eff. = 90 % (when trig eff. is evaluated on MT hits)
BTB 1-3 eff. = 70 % (when trig eff. is evaluated on TDC hits)
Efficiency for trigger MULT2-7 BHA (multiplicity between 2-7 -included-
performed on tofone)
Mult2-7 BHA ~= 70%
this last number is just a pessimistic evaluation since it is not yet
implemented in our code the selection of multiplicity on tofone inside a
gate of 20 ns. Indeed in the trigger such a selection of multiplicity
is done on tofone MT signals which are inside a gate of 20 ns given
by ORtofino. Next week we will give the exact number.
I expect to found out a better value.
What we can see from this values is that trigger modules are working
with very high efficiency, certainly with better values than those
used in rumors. The problems seem to be in something else
before the trigger, I mean for instance on MT signals which go
to the trigger modules.
Simonetta Marcello and Francesca De Mori
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