OK, here you are starring at QOD with RS occupation plots or BV occupation plots and seeing one of the channels missing. (Barrel Veto Liner is the 5-th row in BV occupation plot). You suppress the urge to call the expert and bravely decide to investigate it yourself. Here are steps that can help you locate the module.
Hint: As particles fly from Upstream to downstream numbers also march from Negative to Positive.
Sector is usually on horisontal axis, Layer on vertical
axis. For example you have sector 12, layer 3 and end P. This
module will be referred to as
12P3 OR RS P 12 3 .
First name is used often on cable labels, cabling schemes and so on. Second name is usual in CAMAC initialization programs, HV monitors and so on. Having 2 names for the module is required to satisfy the need of cultural diversity.
Hint: Sector is always preceeding layer.
Barrel Veto Liner is a new device that did not exist in E787. It replaced layer 20 and 21. BV has 48 sectors exactly as many as 2 removed layers did combined together.
So whenever you see labels about RS modules Layer 20 and 21, you are actually dealing with BL. Historically many documentation files, unpacking codes, camac initialization routines, cable and module labels still refer to them as RS Layer 20 and 21. Changing notation would be very confusing, especially if not all the labels are modified. So the file splitter_map.txt (below) includes the translation table between BL sectors, and old notation that you will find almost everywhere.