1. BFEM Trigger Diagnostics Jan 25, 2002 Tsunefumi Mizuno mizuno@hirax6.hepl.hiroshima-u.ac.jp mizuno@SLAC.Stanford.EDU

2. Trigger Layer Distribution (Correction of a minor mistake) Dave Lauben pointed out that TrigXCapture and TrigYCapture seem to be swapped. (below is a forth event of Run55) not X7, but Y7(layer#15) not Y7, but X7(layer#14) not Y3, but X3(layer#6) Anyway, three layers (layer 6, 14, and 15) do not participate to Trigger. (As you have heard) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 --------------------------------------------------------------------------------------- o o o o o o o o o o o o o o o o o x x o o x x o x o Hit o o o o o o o x o o o o o o x x x o o x x o o x o x Trig swapped

3. Trigger efficiency of each layer Hit Trigger Layers other than #6, 14 and 15 are not perfect! Swap of TriggerXCapture/TriggerYCapture is fixed.

4. We need to solve following questions What causes this inefficiency? How to fix the problem in GLAST Satellite? How to estimate the efficiency? (necessary to derive particle flux) Hit Trigger Select events where layers from 0-5 cause trigger. Layer 23 seems to miss more than 50% trigger.