Primary goal of double rapidity gap trigger is to collect data with lowest possible TPC multiplicity (>=2) .
We should avoid increase this threshold to  for example >=4 !

Topological cut on TOF hits  does not help. Suggested by Ramiro back-to-back configuration does
not improve the trigger. This is seen on "bcn_beam_btb.pdf" plot which shows bunch crossing distribution
of back-to-back,  #TOF=2 events with |Delta Phi-180| < 30 degree. We still do not see significant suppresion
of abort gaps region.   Distribution is similar to the one obtained without back-to-back requirement (bcn_beam.pdf)

In ma case bunch number ing is shifted by 60 compared to Ramiro's plots so abort gaps
are slightly above 60 and 100

The only possible improvment is to add additional information (detector components) to the TOF .
It may be calorimeter or VPD. 

It was proofed that coincidence with VPD on any side makes the trigger
clean ("bcn_beam_vpd.pdf") and does not bias TOF/TPC information.
We still analise double gap events where proton breaks up into the small
mass state instead of beaing in unknown state.
 
Event sample taken with VPD allows to work out improvements.

For example check TPC versus TOF    or    TPC verus EMC.