1. MWPC sandwich panels C.Forti INFN-LNF / LHCb-MUON EDR CERN 16 th April 2003 1.sandwich panels typologies of cathodes the mould the production procedure 2.production schedule 3.control of panel quality (weight, planarity, thickness) controls at production site (on all panels) controls on a sub-sample

2. R3 cathode r/o R4 anode r/o M4M5R2 cath r/o M4M5R1 cath r/o M2M3R1 a + c r/o M2M3R2 a + c r/o Many different cathode types depending on the detector region and readout

3. Description of panels The cathode pads of a small M3R3 prototype Cathode pads HV bar

4. Photo of a small prototype A small (~ 50 x 32 cm 2 ) quadrigap prototype for M3R3 region Sandwich panel 4 gaps

5. Description of panels We inject a polyurethanic (0.5 g/cm 3 ) foam between the 2 FR4 foils. Foam vs.honeycomb : PRO’s : cheaper = 10 vs. 50 Euro/m 2 faster production = 20 min. vs. 24 hrs (because of glueing) CON’s : heavier = for an M3R3 panel (4kg=2kg foam + 2 kg FR4) larger X 0 : 1.1% (foam) + 0.8% (FR4) + 0.5% (Cu) / Panel 0.1% (honey) Cu 35  m FR4 0.8/1.6 mm FOAM 7.4/6.2 mm 9 mm

6. The moulds Mould for M3 region small prototypes

7. Mould properties We have 2 moulds: a small one for small chamber prototypes (~ 34 x 28 cm 2 ) a big one for M3 prototypes (~ 136 x 35 cm 2 ) Aluminum: high thermal conductivity Kept at constant temperature with circulating water at 42 0 C Vacuum system to get perfect contact of FR4 to mould surface Closed with clamps (max. 2700 kg each) Fast and easy cleaning before new foam injection

8. Check of the mould planarity After production of ~ 50 panels 18 big (M3R3) and 33 small (~ 35x28 cm 2 ) since we were not completely satisfied, we verified the moulds planarity and found no deformation. Then, we contacted a new firm. Measurements for the M3 mould

9. Mould/panels production schedule 1.The present M3 mould will be modified to fit the new chamber dimensions. Ready at end of may. We plan to produce ~ 300 M3 panels by the end of september. 2.Two new moulds will be produced by the end of october : one for M2M3, the other for M4M5. Total number of panels to be produced ~ 7000 Production rate ~ 20 panels/day if at least 2 moulds work in parallel Total production time ~ 18-24 months R2R2 R1R1 Small panels can be produced putting together in the mould several pieces of FR4

10. The lower half of the M3 mould Vacuum groves

11. The injection point foam injection spacer Water at 42 0 C The foam injection point

12. Positioning of FR4 foil FR4 foil Positioning of the lower FR4 foil

13. Fixing of FR4 foil Fixing of the lower FR4 foil 8.8 mm Rubber 0.2 mm FR4 Frame bar

14. FR4 foils fixed Both FR4 foils fixed

15. Closing of the mould The upper half of the M3R3 mould Closing the mould

16. Closing of the mould Closing the mould Making the vacuum vacuum pipes

17. Connection for foam injection Injecting the foam Engine for injection lasting ~ 15 sec At pressure ~ 4 bars

18. End of injection Injection completed and clamps opened clamps foam vacuum pipes

19. Foam coming out Wait a few seconds after end of injection: the hole is closed after foam comes out

20. Mould reopened After injection, we wait ~ 20 minutes before opening the mould The panel just after mould is opened Total production time is ~ 40 minutes for one panel

21. Tests on panels Tests of fire resistance performed by italian fire corps: (italian) class 1 Mechanical tests (Note: LHCb-MUON 2003-011) on OLD panels Flatwise tensile strength: 2 N/mm 2 to break the sample Flatwise compression: for 200 kg constant load over 25 cm 2, the deformation is ~ 50  m after 600 hrs. Flexural properties of sandwich: deformation ~ 470 N/mm from which we evaluate that the panel sag due to wire tension is < 17  m Facing cleavage of sandwich panels: ~ 6 kN to break the sample (excellent glueing of FR4 on foam) Effect of cold (-30 C) on planarity (one panel tested): within +- 10  m Effect of warm (one week at 40 C) on planarity (one panel tested): +- 30  m Effect of radiation on planarity: 3 panels for ~25 hours at ~80 cm of distance from a Co60 source E  =1.25 MeV. Total ionising dose ~ 10 4 Gray (10 years M1R1): NO EFFECT AT ALL

22. Panel quality control 1.Fast checks at production site (on all panels) Measurement of the panel weight Check of the panel planarity with a ruler Check of the panel thickness (with inductive sensors) Other check on a sub-sample Measurement of panel thickness with a micrometer

23. Measurement of the panel weight The uniformity of the panel weight proves that the injection pressure is constant, so that the foam density (the fraction of air inside the foam) is uniform all over the panel. Max. difference is ~160 g i.e. ~ 4% Panels with gas connectors

24. Planarity check with a ruler 50  m

25. Check of the panel thickness (with inductive sensors) Courtesy Danilo Domenici INFN- ROMA2 INDUCTIVE SENSORS PANEL Panel thickness measured with inductive sensors

26. Measurement of panel thickness with sensors Panel to be measured Facing sensors mounted on a heavy rigid bridge The thickness will be measured by taking the difference of 2 faced sensors Courtesy Danilo Domenici INFN- ROMA2

27. Calibration Sensitivity = 1.23 V/mm Out Voltage vs. distance sensor - panel Courtesy Danilo Domenici INFN- ROMA2 Distance vs. Temperature Slope = -7.5  m/ 0 C Stability of measurement: RMS(10h) = 70 nm !

28. High-tensile Al profile Timing-belt reverse unit Four-row linear guide system Mechanical layout Courtesy Danilo Domenici INFN- ROMA2 Ready by the end of june

29. Measurement of the panel thickness (with a micrometer) INDUCTIVE SENSORS PANEL Sensitivity =10  m 118 points measured all over an M3R3 panel (1364x346 mm 2 )

30. Panel thickness (with micrometer) for last 10 panels produced PANEL =10.10 mm  =37  m =10.07 mm  =44  m All points Only border Thickness specifications: 9.0 < X < 9.4 mm Spread of thickness: 95% of measurements within  90  m

31. Panel thickness (with micrometer) for last 10 panels produced INDUCTIVE SENSORS PANEL vs. N. panel error bar = 2  2  < 80  m for all panels

32. Panel thickness with micrometer measurement mm panel central raw of measurements (2 nd ) Measurements within +- 50  m

33. Conclusions New firm contacted for panel production: first panels produced are within specifications Panel production and quality control procedures are defined Production rate ~20 panels/day Total time 18-24 months Thickness measurement with sensors ready by end of june The M3 mould with new dimensions ready by the end of may A pre-production of ~ 300 panels by the end of September Two other moulds (M2/3, M4/5) ready by october C.Forti INFN-LNF / LHCb-MUON EDR CERN 16 th April 2003