ISOTROPY STUDY IN OB LIGHT OUTPUT Harold Yepes-Ramirez 05/12/2011

STRATEGY: In order to find a way to study the isotropy of the OB light output, two kind of configurations in OB runs were studied, extracted from the optical properties runs list: All top LEDs (L4): All Beacon LEDs (L4): Line 4 as emitter line was selected due to be a central line surrounding the most of neighboring lines to it. Target lines selected: L1, L2, L3, L6, L8, L10.

Special reasoning (by the way)...according to the distance cut for the minimum distance to fit (Rmin), is hits/flashes < 0.1 a very restrictive cut (in terms of the survivor fit points)? In an “All Top” configuration the electronics effects seem to disappear at a distance close to 170±15 m, corresponding to a  (hits/flashes) ≈ 0.3.  < 0.3 is taken to define Rmin used in this analysis. It is translated in more storeys which contribute to the fit.

In an “All Beacon” configuration the electronics effects seem to disappear at a distance close to 200±15 m, corresponding to a  (hits/flashes) ≈ 0.3.  < 0.3 is taken to define Rmin used in this analysis. It is translated in more storeys which contribute to the fit.

ALL TOP RUNS

RUN RUN 58746

ALL BEACON RUNS

RUN RUN 58745

CONCLUSIONS: Isotropy for the OB light output is reached if the “only top” or “all beacon” configuration is set. The results are expected to be compatible with CALIBOB runs. Are we going to perform this kind of runs (we have to increase statistics)? The more distant lines (L1, L10) get the largest errors in the estimation of L. In order to recover the runs which are not “only top” or “all beacon”, could it be a good idea to fit to the line with collects more amount of direct photons? It is very important, overall taking into account that we only have a few of Christmas beacon runs.