Issues on GE1/1 OH clusters seen at OTMB level
Comparison of trigger clusters seen at OTMB level and GEM data path hits revealed some weird inconsistencies. The run analyzed was taken on Dec 15 2021 at the b904 integration stand (ME1/1 + short GE1/1). The VFAT pulse stretch was set to 0 (signal width = 1 BX) for the GE1/1 layer considered here. With this premiss, we should see GEM data from only 1 BX, while OTMB sees GEM trigger clusters in up to 5 consecutive BXs - ±2 BX around the CSC trigger.
If we take a single VFAT, removing the potential timing alignment difference among VFATs:
Issue 1
We should have data path recording clusters only in one of the OTMB BXs (maybe two if the phase between data and trigger path is different and we’re on an edge). BUT, we see it for 4 different ones. And the ones recorded in the data are picked kind of randomly, sometimes at BX = 1, some other times at BX = 2, 3 or even 4. For instance, we do not always see every cluster in the central CSC trigger BX (= 2).
Event a)
OTMB data: 0 Layer 2 ieta: 2 bx: 3 pads: [ 154]
OTMB data: 1 Layer 2 ieta: 2 bx: 4 pads: [ 155]
DAQ data: bx: 0 pads: [ 155] Re -1 Ri 1 St 1 La 2 Ch 11 Et 2
Event b)
OTMB data: 0 Layer 2 ieta: 2 bx: 3 pads: [ 166]
DAQ data: 0 pads: [ 166] Re -1 Ri 1 St 1 La 2 Ch 11 Et 2
Event c)
OTMB data: 0 Layer 2 ieta: 2 bx: 2 pads: [ 158]
DAQ data: 0 pads: [ 158] Re -1 Ri 1 St 1 La 2 Ch 11 Et 2
Event d)
OTMB data: 0 Layer 2 ieta: 2 bx: 1 pads: [ 141]
OTMB data: 1 Layer 2 ieta: 2 bx: 1 pads: [ 134 135 136]
OTMB data: 2 Layer 2 ieta: 2 bx: 2 pads: [ 137 138 139 140]
DAQ data: bx: 0 pads: [ 134 135] Re -1 Ri 1 St 1 La 2 Ch 11 Et 2
DAQ data: bx: 0 pads: [ 137 138 139 140 141] Re -1 Ri 1 St 1 La 2 Ch 11 Et 2
Issue 1 - part 2
One may think that it is due to different timing in different pads. But we see it also in the same pad:
Series of events e)
OTMB data: 0 Layer 2 ieta: 2 bx: 1 pads: [ 71]
OTMB data: 0 Layer 2 ieta: 2 bx: 2 pads: [ 71]
OTMB data: 0 Layer 2 ieta: 2 bx: 3 pads: [ 71]
OTMB data: 0 Layer 2 ieta: 2 bx: 4 pads: [ 71]
Issue 2
Clusters are split among different BXs in trigger path, in weird non-continuous ways.
Event d)
OTMB data: 0 Layer 2 ieta: 2 bx: 1 pads: [ 141]
OTMB data: 1 Layer 2 ieta: 2 bx: 1 pads: [ 134 135 136]
OTMB data: 2 Layer 2 ieta: 2 bx: 2 pads: [ 137 138 139 140]
DAQ data: bx: 0 pads: [ 134 135] Re -1 Ri 1 St 1 La 2 Ch 11 Et 2
DAQ data: bx: 0 pads: [ 137 138 139 140 141] Re -1 Ri 1 St 1 La 2 Ch 11 Et 2
Issue 3
Trigger clusters seen in OTMB are not always ordered by pad number.
- this issue is fixed in MR !119 (merged)
Event f)
OTMB data: 0 Layer 1 ieta: 5 bx: 1 pads: [ 105]
OTMB data: 1 Layer 1 ieta: 5 bx: 2 pads: [ 99 100]
OTMB data: 2 Layer 1 ieta: 5 bx: 2 pads: [ 110]
OTMB data: 3 Layer 1 ieta: 5 bx: 2 pads: [ 116]
OTMB data: 4 Layer 1 ieta: 5 bx: 2 pads: [ 112 113]
OTMB data: 5 Layer 1 ieta: 5 bx: 3 pads: [ 108 109]
OTMB data: 6 Layer 1 ieta: 5 bx: 3 pads: [ 117]
OTMB data: 7 Layer 1 ieta: 5 bx: 4 pads: [ 107]