Neutron Identification
======================

In the graphs asymmetries for different neutron identifications are
compared. The top graph has basically no cuts applied whereas the
lower graph has cuts in
cointime  -2. 3.
w  0.90 1.0        
Ypos -45.0 45.0
Emiss -0.05 0.05
thetaQN 0. 10. 

Analyzer:
Tracks are determined in the analyzer based on clusters of
bar hits. Veto detectors that are on the track are checked for
hits within a time window of +/-5ns. If there is a hit the veto is
declared as active. Up to 3 tracks are written to the ntuple.

Ntuple anlysis:
In case of multiple tracks the one with a meantime closest to the centroid
is chosen, as the most probable one.

particle Id's:
ID1: hardcoded analyzer neutron (similar to ID3, but more restrictive on multiple tracks) 
ID2: both vetos are not active
ID3: both vetos not active and no hit in top 5 bars of first bar
plane
ID4: both vetos are not active and no hit in first bar plane
(first bar plane used as veto too)
ID5: veto1 not active and no hit in top five (checking efficiency
of a single veto) 
ID6: veto2 not active and no hit in top five (checking efficiency
of a single veto)

Conclusions:
loose cuts: ID3 is good enough (same as ID4) but ID2, ID5 and ID6
show proton contamination
hard cuts: All ID's are good, mainly due to proton
suppression with the thetaQN cut.