Development of a Liquid Scintillator and of Data ... - Borexino - Infn

7.4 Analysis of the Source Runs
The two codes do not agree perfectly, but the difference in the reconstructed positions is for
most locations still within the error of the nominal position. The Milano reconstruction exhibits
a systematic shift in the positive x-direction for large negative z-values (run 802 - 805).
This could be a hint that in this reconstruction code the mapping between PMT position and
electronic channel is done in the wrong way for some PMTs on the lower rings. The Munich
code doesn’t show this systematic drift.
The spatial resolution for the Po alpha events for the two different reconstruction methods
is given in table 7.3 for the individual source positions. They are also compatible.
Spatial resolution of Po alpha events
Milano Code Munich Code
Run nom. position Ü (cm) Ý (cm) Þ (cm) Ü (cm) Ý (cm) Þ (cm)
791 0, 0, 32 12.8 10.3 13.0 12.5 11.3 13.4
793 0, 0, 0 12.6 10.7 13.6 12.2 11.5 13.3
797 0,48,0 16.9 13.9 17.1 16.1 14.9 16.7
798 -48,0,0 15.3 13.4 16.3 14.9 14.5 17.5
799 27,-40,0 17.1 13.4 17.3 16.6 14.6 17.3
800 40,-27,-30 17.3 13.3 18.0 16.0 14.4 17.4
801 -40,27,-30 16.0 13.2 16.0 15.6 14.6 17.1
802 0,0,-78 18.7 14.5 17.1 17.3 16.4 18.2
803 0,0,-83 18.4 14.1 16.1 17.6 15.8 18.7
804 0,0,-75 18.4 14.7 17.0 18.0 16.7 17.8
805 0, 0,-62 16.6 14.1 16.9 15.9 15.8 17.3
807 -40,27,-56 16.5 13.9 16.3 17.0 15.9 18.8
809 -40,-27,-56 16.8 13.7 16.6 17.7 15.5 18.5
810 27,-40,11 16.8 13.5 17.4 16.3 14.9 17.2
Table 7.3: Comparison of the spatial resolution of the Milano and Munich reconstruction program
for different source positions. Given is the standard deviation of a Gaussian fit to the distribution
of the reconstructed events.
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