1. Engineering Design Review for TRD-Readout Chamber
Mechanical Design
Bernd Windelband
University of Heidelberg

2. TRD and TPC in Space Frame

3. ROC Segmentation in Individual Layers

4. Different Types of ROC‘s
ATRD0901P6
16 different types of ROC‘s from
1080mm x 974mm x 105mm, type L1C0 to
1585mm x 1196mm x 105mm, type L6C1,

5. ROC L6C1 (1585mm x 1196mm)

6. Mechanical Requirements of ROC
to keep wire tension (~90kg) and drift gas overpressure (1mbar)
to ensure required flatness of padplane (<200µm) and radiator (<1mm)
 very rigid structure
small radiation length („made out of nothing“)
radiator and pad- readout panel have to be sandwich structures

7. ROC Cross Section, View in z
each chamber consists of
48mm radiator
37mm drift volume with wire planes
~20mm backing structure with pad plane
main frame with radiator serves as the main support structures to hold the wire tension.
pad plane does not see the wire load.

8. ROC Cross Section, View in φ
Pad- Readout panel
Voltage Divider
Frontplate with
Chamber to Chamber
Sealing Connection

9. Chamber to Chamber Sealing Connection
Quad-Ring-Seal unit glued to frontplate
connection with PEEK tube, di=17mm
serves at the same time as chamber to chamber alignment

10. Thickness Determination of the CF-Layers for Pad- Readout Panel and Radiator
20mm core thickness
fmax <= 200μm
Result: 0.4 mm
f = (c3 · p · b4 )/(6 · ED · t · (t + c)2)
t = thickness of carbon fibre facing,
p = pressure load
c = thickness of the core material,
ED = Young’s Modulus of the layer,
2a = panel length,
2b = panel width,
c3 = correction function (a/b, load case).
Radiator,
48mm core thickness
fmax <= 1mm
Result: 0.1 mm
case 1 =clamped
case 2 = simply supported

11. Full size Prototype L6C1 Chamber Components – Production and Assembly
Pad- Readout Panel -> INVENTOR (Krakow)
-> PI Uni Heidelberg (cutouts, glueing of pad planes)
Radiator -> INVENTOR (panels)
-> IKP Uni Muenster (assembly)
Main frame, wire ledges, etc. -> PI Uni Heidelberg (production and assembly)
Three main production steps:
glueing main frame to radiator
electrical connections and applying the wire planes
closing the chamber with pad- readout panel

12. ROC Prototype L6C1, Radiator

13. ROC Prototype L6C1, Test Assembly

14. ROC Prototype L6C1 Main Frame glued to Radiator

15. ROC Prototype L6C1 applying additional layer of glue along the rim

16. Purpose of L6C1 Prototype
Load from wires and drift gas pressure most critical for largest chamber
Verify design of largest chamber -> L6C1
behavior of main frame under wire load
deformation of pad- read out panel and radiator under overpressure
to learn assembly procedure and application of the wire grids
test of chamber performance (Harry)

17. Wire Tension Test

18. Wire Tension Test - Detail

19. Measurement of the Deflection

20. Deflection of Chamber Side Profile under Wire Tension

21. ROC Prototype L6C1 voltage divider

22. ROC Prototype L6C1 applying the wire planes

23. Wire Tension on Winding Frame and on ROC

24. Padplane for Prototype
connector side
Pad side

25. Prototype on Test Stand

26. Further Results of Tests
Chamber main frame deformes 150 μm under wire tension indicated in TDR -> 10% loss in wire tension.
Additional tooling necessary for chamber assembly
-> mounting table for chamber frame.
-> computer aided measurement sytem
Deformation Pad- Readout Panel and Radiator under overpressure within the requirements (talk of Harry and Damian).
Large capacitance between Carbon fibre layer close to padplane and padplane
-> replacement of this CF-layer by insulating material (glass fibre, Kevlar).

27. Infrastructure for Chamber Production
mounting tool for the chamber main frame and glueing to radiator
flat tables
vaccumtable (glueing pad plane to pad- readout panel)
cleanroom and wire winding machine (to produce and glue the wiregrids to the chamber)
milling machine with min. 1,6m machining length (production of chamber main frame parts)
computer aided measuring system

28. Mounting Table for ROC

29. New Wire Winding Machine

30. Glass Table and Crane in the New Cleanroom

31. Refurbished Milling Machine

32. Computer Aided Measuring System (Hecht)
-> System will be adapted to our table size and specific needs

33. Next Steps Production of Chamber Stack.
Production of Chamber Mounting Table.
Test of Pad- Readout Panels with Kevlar, Kevlar-Tedlar and Glassfibre layer instead of CF.
Final Set up of Cleanroom
Installation of Measuring System