1. GEM, Resistive M-Bulk, ThGEM detector production. Rui De Oliveira, Cosimo Cantini, Antonio Teixeira, Olivier Pizzirusso, Julien Burnens Annecy 26/04/2012 26/04/121Rui De Oliveira

2. CERN PCB Workshop 26/04/12Rui De Oliveira2 18 persons Building :1000 sqr meters Making PCBs since 1960 -PCB -Rigid -Flex -Flex-rigid -Micovias -fine line (15um) -large size (up to 2m) -Thick film Hybrids -Thin film Hybrids -Chemical milling -Cu, Fe, Al, Au, Ag, W, Mb, Ti, Cr, Ni -MPGD -GEM/thinGEM/THGEM/RETHGEM -MSHP/Cobra -MICROMEGA/ Bulk/ Micro-BULK -RES BULK -Resistive MSGC -Low mass circuits -Multilayer flexes with aluminum strips -embedded heat sinks (carbon, graphite, metals, diamon) -Embedded components -passive -Active

3. GEMGEM Large size situationLarge size situation Detector without spacersDetector without spacers MicromegasMicromegas Large size situationLarge size situation X/Y and U/V/W readoutX/Y and U/V/W readout Thick GEMThick GEM Large size situationLarge size situation ProtectionProtection 26/04/123Rui De Oliveira OUTLINE

4. 26/04/12 Rui De Oliveira 4 GEM Foil Present size 1.2m x 0.6m Future max size 2m x 0.6m Std pattern 140um pitch/70um holes

5. 26/04/12 Rui De Oliveira 5 Base material : Polyimide 50um + 5um on both sides Polyimide : Apical NP from company Kaneka (Japan) Supplier of the copper clad material : Nippon Mining (Japan) GEM double mask Vs GEM single Mask Same base material Hole patterning in Cu Polyimide etch Bottom electro etch Second Polyimide Etch Limited to 40cm x 40cm due to Mask precision and alignment Limited to 2m x 60cm due to Base material Equipment Double maskSingle mask

6. 26/04/12Rui De Oliveira6 GEM Double mask Vs GEM single Mask Similar patterns, similar behavior, same material. Angles can be adjusted in both structure (Typ value : 70um copper hole, 50um polyimide hole) Steeper angles gives lower gain but also lower charging up

7. COMPASS (CERN) 7 GEM double mask examples LHCb-Muon trigger (CERN) TOTEM (CERN) Window Drift electrode GEM stack Pad Plane Support & Media-Distribution Cooling Support & LV- Distribution Front-End Electronic Shielding Cover & Read-out Plane STAR experiment (US) 26/04/12Rui De Oliveira Present double mask production quantities : around 500 GEMs/ year in average Max size: 40cm x 40cm

8. 8 GEM Single mask examples KLOE – Cylindrical 3 GEM Detector GEM 800mm x 500mm Read-out 2D : 800mmx 500mm CMS RPC possible upgrade GEM 1.1m x 500mm Present production rate : 100 Gem /year (1.2mx0.6m) Expected rate for 2012 : 250 GEM/Year/technician 26/04/12Rui De Oliveira

9. GEMGEM Large size situationLarge size situation Detector without spacersDetector without spacers MicromegasMicromegas Large size situationLarge size situation X/Y and U/V/W readoutX/Y and U/V/W readout Thick GEMThick GEM Large size situationLarge size situation ProtectionProtection 26/04/129Rui De Oliveira

10. No spacer No stretching structure: NS2 26/04/12Rui De Oliveira10 10 to 15mm Readout connector O-ring GEM attaching structure (4 pieces defining gaps) Drift electrode Free to slide External screws to adjust stretching GND gluing

11. 26/04/12Rui De Oliveira11 FRAME GEM HV DIVIDER DRIFT BOARD CLOSED DETECTOR 30 x 30 cm Screws O-ring HV BNC Connector Gas connectors Read-out connectors 1m x 0.5m under production

12. No spacers in active area Assembly time ½ hour for 10cm x 10cm detector (1 technician) 2 hours for 1m x 0.6m detector (1 technician) No gluing, no soldering Re opening possible GEM exchange possible Full detector Re-cleaning possible No intermediate test New GEM stretching method (NS2) advantages: 26/04/1212Rui De Oliveira

13. GEMGEM Large size situationLarge size situation Detector without spacersDetector without spacers MicromegasMicromegas Large size situationLarge size situation X/Y and U/V/W readoutX/Y and U/V/W readout Thick GEMThick GEM Large size situationLarge size situation ProtectionProtection 26/04/1213Rui De Oliveira

14. 26/04/1214 PCB lamination Mesh deposit lamination development Rui De Oliveira Large Micromegas Largest size produced: 1.5m x 0.6m Limited by equipment BULK Technology DUPONT PC 1025 coverlay BOPP Meshes SERITEC stretching

15. 15 Fine segmentation 1cm², thickness 8mm for ILC Hadronic calorimetry Tested in the RD51 1 kHz beam Bulk Micromegas ILC DHCAL first m 2 LAPP Annecy 26/04/1215Rui De Oliveira Pad read-out large TPC Neutrino detector 10 sqr meter in service T2K experiment Japan

16. Atlas CSC replacement project 26/04/12Rui De Oliveira16 MPGD Vs Wire chambers -Faster -no need for fancy gases -lower cost -robust 1.2m x 0.6m

17. Resistive Bulk MicroMegas structure 26/04/12Rui De Oliveira17

18. 26/04/12 Rui De Oliveira 18 Resistive strip process PCB -Good resistor uniformity -Easy to clean -Thermally robust Read-out strips or pads Copper lamination layer Resistive inverse patterning Resistive layer deposition Copper stripping

19. 26/04/12Rui De Oliveira19 Atlas CSC replacement project Double sided Board Resistive strip deposit Bulking Test before closingClosing

20. 26/04/12Rui De Oliveira20 Situation and on going productions Situation on large STD BULK – Up to 5 detectors (1.5m x 0.6m max) produced  all good Situation on large resistive detector production – 4 CSC type (1.2m x 0.6m) 1D produced  1 good Physical parameters OK, leakage current out of tolerance – 4 MSW type (1.2m x 0.6m) 2D produced  1 good Physical parameters OK, leakage current out of tolerance – Yield 25% due to dust contamination (solution found recently) – Ionic contamination and pillar shape are not the cause of leakage currents Next production with corrections – 1 detector 1 m x 1m end of June

21. GEMGEM Large size situationLarge size situation Detector without spacersDetector without spacers Compact HV dividerCompact HV divider MicromegasMicromegas Large size situationLarge size situation X/Y and U/V/W readoutX/Y and U/V/W readout Thick GEMThick GEM Large size situationLarge size situation ProtectionProtection 26/04/1221Rui De Oliveira

22. Resistive strips Bulk MicroMegas resistive anode and 2D readout 26/04/12Rui De Oliveira We have produced : X/Y read-out U/V/W read-out Grounded mesh detectors 22

23. 26/04/12Rui De Oliveira23 X/Y read-out U/V/W read-out

24. GEMGEM Large size situationLarge size situation Detector without spacersDetector without spacers Compact HV dividerCompact HV divider MicromegasMicromegas Large size situationLarge size situation X/Y and U/V/W readoutX/Y and U/V/W readout Thick GEMThick GEM Large size situationLarge size situation ProtectionProtection 26/04/1224Rui De Oliveira

25. 26/04/12Rui De Oliveira25 THGEM description: -800mm x 400mm Halogen Free -1mm & 2mm thick -RIM 40um (differential etching) -0.8mm pitch -0.5mm hole diameter @ ELTOS: -Drilling -Photolithography -Differential etching @ CERN: -Thermal treatment -Passivation -Cleaning -Electrical Test THGEM and read-out for Double phase pure argon LEM-TPC with 2D anode

26. GEMGEM Large size situationLarge size situation Detector without spacersDetector without spacers Compact HV dividerCompact HV divider MicromegasMicromegas Large size situationLarge size situation X/Y and U/V/W readoutX/Y and U/V/W readout Thick GEMThick GEM Large size situationLarge size situation ProtectionProtection 26/04/1226Rui De Oliveira

27. THGEM: limitations Strong ionizing particles produce sparks. Sparks damage the electrodes and are responsible of a low degradation of the gain. The active element then drains steadily a DC current from the power supply. 27 Ideas to cancel the phenomenum : -increase the number of TH GEM (we want to avoid) - Reduce the capacity by segmenting the THGEM - Decouple sectors with resistors - Resistive electrodes - Change metal - Rim, no rim -Change dielectrics After long sparking period they all failed but some structures are 1000 time better than others We went back to theory to understand the problem 26/04/12Rui De Oliveira

28. Voltage-Current Characteristic of the DC Electrical Discharges - Gas Discharge Physics, Yuri P. Raizer - DC pulse-powered micro-discharges on planar electrodes, Yogesh B. Gianchandani Breakdown triggered Self maintained 28 C :negligible avalanche Corona Glow discharge Spark 26/04/12Rui De Oliveira

29. 29 V: supply voltage (2KV) R: limiting resistor (1Mohms) C: THGEM capacity (1nF) R’: spark local surface resistor (10 Ohms) : spark I : charge current I’: discharge current inside capacitor Charge  T = RC (1us)  I max =V/R= 2mA (limited to 10uA) Spark discharge  T = R’C (10ns)  I’ max = (200 A) That’s consistent with measurements C VcV I I’ 26/04/12Rui De Oliveira

30. 30 Initial Working point R’ low value Repetitive sparks End working point R’ value > R DC current R’ increase Due to spark damage ex:1 MOhms R’ is low Clean metal ex: 10 Ohms 26/04/12Rui De Oliveira

31. ? 26/04/12Rui De Oliveira31 High energy Sparks Glow discharge Perfect Hole ? Low energy sparks?

32. Thank you Questions? 26/04/12Rui De Oliveira32