BUNDLE  UNIFORMITY  FIRST  TEST  RESULTS  First tests were done with a bundle of 24 fibers 10 meters long
with 1 control fiber 5 meters long.
 For this tests to diffuse LED light two variants were used.
In one measurement - square pattern difractive diffuser D0310A from
ThorLabs Inc. (14.9/11.9 degrees). In second measurement a combination
of this diffuser and a lucite block with both ends scratched was used.
Results are presented on  Bundle uniformity test picture. Fiber #1 here
is a control fiber 5 meters long and should have more light output.
After a visual inspection some fibers have found to be with some
cracks on polished surface (#4, #15, #16 on pictures), but only
channel #16 is to be significantly affected by this irregularities.
 Other ends were positioned one by one on 1/2" distance approximately
in the center of PMT window. This ends are cleaved only, not polished.
After excluding from distribution a bad fiber (#16) and a control fiber
the result is Mean Ampl= 629.8 with RMS = 87.2 (14%).
 There are 3 main factors contributing to this RMS. One is the fiber
itself, 2nd is positioning of fiber end, 3rd is a light pattern
irregularity on the bundle end. Two measurements Correlation
picture is a fitted plot of 1st measurement vs 2nd one. It shows a
rather good correlation, but also some light source pattern
irregularity.
  Any comments, questions, suggestion are very welcome.
                                   Best wishes, Sasha.