june 11, 2003tkr geometry review1 review of tracker geometry overall view recent bug fixes –offset...
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June 11, 2003 TKR Geometry Review 1
Review of Tracker Geometry
• Overall view• Recent bug fixes
– Offset– Wrong Converter
• Typical tray• “Active” tracker
– Vertical dimensions• Groupings• Radiation Lengths
– Horizontal dimensions
• “Passive” tracker– Closeout– Walls– MCM– Other
• Cables• Heat Straps• Flexures• Bosses• ???
June 11, 2003 TKR Geometry Review 2
Overview
June 11, 2003 TKR Geometry Review 3
Zoom In
June 11, 2003 TKR Geometry Review 4
More Zoom
June 11, 2003 TKR Geometry Review 5
Comparison of Previous & (Mostly) Corrected Geometry
Previous New, 1st Draft
June 11, 2003 TKR Geometry Review 6
Detail
Previous New, 1st Draft
June 11, 2003 TKR Geometry Review 7
Wrong Converter
• A one point, the material for the SuperGlast converter was changed from pure tungsten to a tungsten alloy.
• Since the alloy is less dense, the thickness of the converter had to be increased to yield the same radiation length.
• This was done, but the material was left as pure tungsten.
• Fixed now…
June 11, 2003 TKR Geometry Review 8
Vertical Dimensions of Stack (mm)
June 11, 2003 TKR Geometry Review 9
Horizontal Dimensions
• Nothing has changed since the last iteration.• In the last design, the top and bottom ladders
on a tray were translated in opposite directions along their length so that they were out of register by about 1.5 mm. – This was never modeled in the geometry.– BJ says this “feature” has been eliminated from the
current version.
June 11, 2003 TKR Geometry Review 10
Side View of a Typical Tray in a Tower
Tray
Silicon
Face Sheet
Bias Board
Tungsten
Glue
Closeout
Core
D
d = 2.05 – 2.1 mm
Ladders
“Boss”
Boss, closeout and spacer are not part of
geometry model
dc = 27.92 mm**Top, Bottom, larger
Not to Scale!!
Wall
Spacer post
June 11, 2003 TKR Geometry Review 11
Details of Top Face of Trays(all trays the same, except top tray)
siThick, 0.400 mm Glue, 0.150 mm
Bias plane, 0.100 mm
Glue, 0.100 mm
faceThick, 0.200 mm(SuperGlast/Bot 0.290)
Not to Scale, separated to indicate grouping!
Core
Glue, 0.075 mm(dots)
Top Face
June 11, 2003 TKR Geometry Review 12
Details of Bottom Face of Standard Tray, including Bottom Face of Top Tray
Silicon, 0.400 mm
Glue, 0.150 mm
Bias plane, 0.100 mm
Glue, 0.075 mm
Not to Scale, separated to indicate groupings!
convThickReg, 0.105 mm Tungsten
Core
Face sheet, 0.200 mm
Glue, 0.100 mm
Bot Face
Bot Bias
June 11, 2003 TKR Geometry Review 13
RadLen vs Z
0
10
20
30
40
50
60
70
0 10 20 30 40 50 60 70 80
Z
Ra
dL
en
(g
/cm
2)
Radiation Lengths for some common Materials
H
O
C
Al
Fe
Si
Cu
W
Kapton, Mylar
G10
Polystyrene
CsI
June 11, 2003 TKR Geometry Review 14
Example of Composite Material Calculation
June 11, 2003 TKR Geometry Review 15
Composite Material Calculation, continued
X0(C) = 42.7
June 11, 2003 TKR Geometry Review 16
Another Calculation
June 11, 2003 TKR Geometry Review 17
Another Calculation, continued
X0(C) = 42.7
June 11, 2003 TKR Geometry Review 18
Summary of “Active” Radiation Lengths
• Converter 1.0850• Silicon 0.1584 • Core 0.0513
• BotFace 0.0363 ?• TopFace 0.0341 ?• BotBias 0.0250
• Top 3 items are simple elements; 93% of r.l.
• Remaining 3 are composites; mostly carbon, with Si, Cu, etc.
• TopFace is thicker than BotFace; should show more r.l.; Found a typo!
June 11, 2003 TKR Geometry Review 19
Passive Tracker
• Walls: Carbon Fiber, bolts, Al coating • MCM: Calculation based on BTEM module ½
– Could be redone, if we had the info
• Closeout– Complicated shape; dimensions and effective density
should be reviewed.
• Other material not in model– Cables– Flexures– Heat straps– ???
June 11, 2003 TKR Geometry Review 20
Conclusion
• Recent discovery of bugs has prompted a careful review of our model.
• Several new (minor) bugs have been uncovered.
• Minor design changes since last implementation need to be incorporated.
• Modeling of passive tracker should be re-examined.
• No big changes are expected.