collision analysis svd meeting markus friedl (hephy vienna) 18 june 2015
TRANSCRIPT
Collision Analysis
SVD Meeting
Markus Friedl (HEPHY Vienna)
18 June 2015
Markus Friedl (HEPHY Vienna)
Distance Between Ladders
• (Not really) collision analysis: looking at various spots where neighboring objects are close to each other
• Generally: 1mm minimum gap (with exceptions)
• Some cases look like a problem (in a 2D projection) but in fact aren’t (when looking at different angle in 3D model)
218 June 2015
Markus Friedl (HEPHY Vienna)
Barrel Cross Section
318 June 2015
1
5
3
4
2
6
Symmetry:Same occurrences in left and right halves
7
8
Proximity issues (all between L4 and L5)
DSSD distance of neighboring ladders
Markus Friedl (HEPHY Vienna) 418 June 2015
1
3 4
0.33 mm
0.84 mm 1.32 mm
0.46 mm
2
Markus Friedl (HEPHY Vienna) 518 June 2015
6
7 8
2.59 mm
2.74 mm4.27 mm
5
1.88 mm
No wirebonds near edge
Minus wirebondHeight ~2.0 mm
Minus wirebondHeight ~2.0 mm Minus wirebond
Height ~3.5 mm
UPDATE
BondsMeasured height ~0.5 mm
Markus Friedl (HEPHY Vienna)
Barrel Near L4 Knee
618 June 2015
1
2
Same occurrences on the other half (L4, L5, L6 are symmetric)
UPDATE
Markus Friedl (HEPHY Vienna) 718 June 2015
1 2
0.93 mm
Not an issue (looks like one only in 2D projection)
3.23 mm min distance
0.33 mm
0.46 mm
UPDATE
Markus Friedl (HEPHY Vienna)
Barrel Near L5 Knee
818 June 2015
1
2
Same occurrences on the other half (L4, L5, L6 are symmetric)
UPDATE
Markus Friedl (HEPHY Vienna) 918 June 2015
1 2
0.16 mm
0.33 mm
0.46 mm
0.16 mm
Possible remedy: local dent in L6 ribs similar to L5 ribsUnder investigation at HEPHY (where all the final L6 ribs are)
UPDATE
Markus Friedl (HEPHY Vienna)
Forward Cross Section
1018 June 2015
1
2
Same occurrences on the other half (L4, L5, L6 are symmetric)
Markus Friedl (HEPHY Vienna) 1118 June 2015
1 2
1.13 mm
0.33 mm
0.46 mm
0.97 mm
This is the reason for the local dent in L5 ribs
UPDATE
Markus Friedl (HEPHY Vienna) 1218 June 2015
Wide sensor edge
4.11 mm
2.78 mm
1.28 mm
4.38 mm
Narrow sensor edge
L6 FWD Gaps Between Ladders
Rib to PF1 Connectors
UPDATE
Markus Friedl (HEPHY Vienna)
Backward Cross Section
1318 June 2015
3
1 & 2
1 & 2 occur between all L4 ladders
Markus Friedl (HEPHY Vienna) 1418 June 2015
1 2
3
1.13 mm
0.63 mm
1.26 mm Not an issue (looks like one only in 2D projection)
Better to make the clamp a bit narrower (to achieve at
least 1mm gap)
15Markus Friedl (HEPHY Vienna)
BWD L4 Connectors
• That’s why we need to connect the BWD L4 cables before mounting the ladder (similar to the L3 case)
18 June 2015
0.95 mm
16Markus Friedl (HEPHY Vienna)
Comparison CAD – Reality
• Measured on L5.902 (class C)– 2 PA1 & 2 PA2, each measured on both sides– Good match of average and CAD
18 June 2015
CAD = 3.73 mmReality:Min = 3.25 mmAvg = 3.74 mmMax = 4.10 mm
CAD = 2.25 mmReality:Min = 2.06 mmAvg = 2.28 mmMax = 2.56 mm
Markus Friedl (HEPHY Vienna)
Assessment
• Gap between adjacent DSSD sufficiently large to allow some sagging without collision– 1.88mm (L3) to 4.27mm (L6)
• Generally 1mm minimum gap except for cases mostly between L4 and L5 (and L5 to L6) with PA1/2 loop (flexible)
• Average PA1/2 bend in CAD matches well with reality, but 0.5mm tolerance in height (~0.3 length)
• Tolerances may lead to PA1/2 touching adjacent rib– No Ohmic issue because of PA coverlay– Maybe noise issue? (Capacitive coupling)– Maybe add Kapton tape around bottom of L5 & L6 ribs?
1718 June 2015
Markus Friedl (HEPHY Vienna)
Action Items
• L6 rib to L5 FW clip: 0.16mm– Possible solution: make local dent in L6 ribs– Under investigation at HEPHY
• Adjacent CO2 clamps in L4: 0.63mm– Slightly reduce clamp thickness at end
1818 June 2015
UPDATE