Light Injection Mapping at the Far Detector

The pulser boxes have two labels. An OMC label which counts the CalDet pulser box as 1, and the FarDet boxes as 2,3,4,etc in the order that they are made. The second label is for the plex and is more useful when trying to locate a pulser box in the mine: pulser box 0 is in VME crate 0, etc..

Therefore,

0 corresponds to the first pulser box on the east side which pulses the first 64 planes (OMC label = 3)

1 is the first west side box which pulses the other side of those 64 planes (OMC label = 2)

Assuming this pattern continues through the detector, box 2 will flash planes 65-128 on the east side and box 3 the same planes on the west side, etc.
 

In terms of LED number, the simplest way to map is to first work out which ashtray in the LIMs is being flashed.  Always count the ashtrays from bottom to top in a plane so a particular ashtray always corresponds to the same set of strips.

For planes 1,2,5,6,...4n+1,4n+2... there is a one to one correspondance between LED number and ashtray so LED 1 is LIM 1, etc

For planes 3,4,7,8,...4n-1,4n... each LED number corresponds ashtray number - 1. i.e. LED 20 is LIM 19, LED 4 is LIM 3, LED 1 is LIM 20, etc.
 

IMPORTANT: Remember that with the introduction of step dowels, the LED order is reversed. The fibre that was flashed by LED 1 is now flashed by LED 20, etc
Mapping to LIM therefore becomes:

For planes 1,2,5,6,...4n+1,4n+2...  LIM = 21-LED  (i.e. LED 3 now flashes the fibre labelled 21-3=18 in the bundle, so LIM 18 is illuminated)

For planes 3,4,7,8,...4n-1,4n... LIM = 20-LED  except when LED = 20, LIM=20
 

Once you have LIM number, then the corresponding strip-ends are as follows:

lim=1 : strip 1-8
lim=2 : strip 9-18
lim=3 : strip 19-28
lim=4 : strip 29-36
lim=5 : strip 37-46
lim=6 : strip 47-56
lim=7 : strip 57-66
lim=8 : strip 67-76
lim=9 : strip 77-86
lim=10 : strip 87-96
lim=11 : strip 97-106
lim=12 : strip 107-116
lim=13 : strip 117-126
lim=14 : strip 127-136
lim=15 : strip 137-146
lim=16 : strip 147-156
lim=17 : strip 157-164
lim=18 : strip 165-174
lim=19 : strip 175-184
lim=20 : strip 185-192
 

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