RHS Gamma catcher wrongly corrected during 1997
It appears that the right hand (side 1) gamma catcher is incorrectly
connected.
A plot of PhiLeft vs PhiRight
[ NOT YET AVAILABLE WITH SUFFICIENT STATS ]
for events with clusters
both ends shows that PhiLeft = PhiRight, rather than PhiLeft = PhiRight+pi,
as would be expected for Bhabha scattering.
A comparison of PhiFE vs PhiFK for the RH detectors confirms that the
Right detector is wrong. ( Second plot, same page )
A fix has been introduced in FD428/03 to correct this, and so the next
Rope pass should be OK.
Plots 3 and 4 show the
corrected distributions.
Many thanks to Graham Wilson for discovering this interesting feature.