1. Recent achievements and projects in Large MPGDs Rui de Oliveira 21/01/2009 RD51 WG1 workshop

2. Content Large GEMs –CERN production situation –Companies contacts Large Bulks –CERN production situation –Resistive protection –Companies contacts

3. Large size process Conventional process : ok but difficult LDI : Problem of alignment Large glass mask : mask planarity problem Single mask + electro-etch: not accurate Single mask + chemical selective etching: ok

4. Raw material Single side copper patterning Chemical Polyimide etching differential etching or second metal etch Single mask technique quick reminder

5. 100 meter 500mm 2 meter x 500mm 100 meter x500mm 2 meter x 500mm Resist development Resist laminationUV exposureRaw material Copper etchPolyimide etchDiff etch Drying GEM 2 meter x 450mm Active area In theory with CERN equipments

6. 70um 55um 50 to 60um STD Single mask Goal 2 meter x 450mm GEM Single mask process 2um Copper on both sides

7. Single Mask GEMs produced in 2008 (650mm x 400mm) Problems: -large rims on the top -up to 90um copper diameter on top -uniformity on large pieces -lower gains Bottom Top

8. Bottom Single Mask GEMs produced in 2009 (30mm x 30mm)!! Problems: -Still some delamination on top layer -Hole shape to deep for classical differential etching -Needs a protecting metal before second spray etch -uniformity seems good but need to be verified -Up to 30 different chemistry tested (for polyimide) -Effect of ultrasonic bath tested (for polyimide and metal) -NI/Au protection layer tested -removable Tin for production still to test

9. Chemical Polyimide etching stripping : Tin on top Resist on bot Detail on second metal spray etch NI/Au or Tin plating on top Resist protection on bot Conventional spray etching

10. Next large GEMs productions –Kloe 700mm x 450mm –DHCAL 1000mm x 330mm 2 slides following given by Mr Jae Yu

11. UTA’s 100cmx100cm Digital Hadron Calorimeter Plane

12. Base steel plate, t=2 mm Readout Board 330x500 mm 2 990 mm 1000 mm

13. Visit November 2008, organized by Changwon university Company: NEW flex technology Started in 1992 Activities: circuits for Telecom, displays and Automotive 400 Employee Situation: South Corea near Seoul Future large volume production

14. Double sided flexes capacity 10 000 m2/month !

15. Smaller than needed for GEMs

16. Roll to roll exposure, etching and stripping

17. Strategy for low to medium volume Use the CERN equipment Create tool to handle 2meter GEMs for chemical treatment (done) Subcontract artwork ( 0.5m x 2m) (Ok) Upgrade UV exposure and Polyimide etching equipment ( but still dead baths) –Existing ones sufficient to start

18. Strategy for large volume Subcontract roll to roll copper patterning Buy or create equipment for roll to roll polyimide etching (spray or static etching) Buy equipment for roll to roll Tin plating Buy equipment for roll to roll Tin stripping Subcontract roll to roll electrode definition Buy equipment for roll to roll cleaning

19. Micromegas Bulk About to start 1 large Bulk for SLHC –Should be built within 1 month Points to be verified (production) –size capability –Resistive protection against discharges –Mesh sectors creation

20. Drift frame Gas box 6 different patterns Mesh 1500mm x 500mm Outer size 1300mm x 350mm Active area

21. 500 um pitch 400um line and space 250 um pitch 150um line and 100um space 250 um pitch With resistive protection High voltage supply 6 sectors + drift Signal outputs 500um 250um Full plane

22. Signal out Spark or charges PCB Copper Photo-imageable coverlayResistive dot, pad or line Resistive protection 50 to100um

23. Signal out dot Spark or charges R Serial resistor limiting max current High enough to limit energy of spark C Serial parasitic capacitor High pass filter High enough to transfert signal charges

24. Signal out dot Spark or charges R Serial resistor limiting max current High enough to limit energy of spark C Serial parasitic capacitor High pass filter High enough to transfert signal charges Change the paste 100 Ohms to 1 MOhms

25. Signal out dot Spark or charges Change the paste 100Ohms to MOhms Introduce a metallic hat C Increase the distance C R Serial resistor limiting max current High enough to limit energy of spark C Serial parasitic capacitor High pass filter High enough to transfert signal charges

26. Dot architecture -Min : 0.15mm diameter -Pitch: 0.25mm -Possibility to avoid alignment between track and dots Pad architecture -needs alignment

27. 0.8mm 0.6mm Coverlay Read-out board Detail on the sector partitioning Spacer pillar Mesh Milling or scalpel cut Scalpel cut prefered No dust!

28. First contact for large size large volume productions CIRE Group 8 companies in France Possibility to make large patterns in some of them They have already produced some small BULKS Other details are being discussed We are ready to discuss also with any other company

29. Thank you