1. Detector Challenges and New Developments in Micro-Pattern Gaseous Detectors Bo Yu Brookhaven National Lab Workshop on Detector R&D, FNAL, Oct. 6-9, 2010

2.  Overview of major MPGD technologies  A sample of MPGD applications  Technical challenges Outline 2 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

3. Multi-Wire Proportional Chamber 3 Global resistive charge division Cross-strip digital readout Good Position resolution along the wire direction Wire pitch > 1mm Rate capability: 10 4 /mm 2 s, due to space charge Can be constructed in large area ~m 2 Many well developed position encoding methods 1968, Georges Charpak B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

4. Micro Strip Gas Chamber (MSGC) 4 A. Oed, 1988 Greatly improved rate capability and position resolution due to its finer electrode pitch (~100µm) But in high rate / heavily ionizing particle environment: Susceptible to damage due to sparking Substrate charging Aging Limited applications in x-ray / neutron detection B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

5. Gas Electron Multiplier (GEM) 5 V ~ 300-500 V E ~ 60-100 KV/cm 70  m 50  m 5  m 140  m Achieve gas gains ~ 10-20 per foil ~ 10 3 -10 4 or higher in triple GEM structures F. Sauli, 1997 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

6. GEM Performance (COMPASS) 6 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

7. 2D Readout of GEMs Cross Strips R. Bellazzini et al Nucl. Instr. and Meth. A478 (2002) 13 A. Bressan et al, Nucl. Instr. and Meth. A425(1999)254 Strip Pixel (3 sets of strips to resolve multiple hits) True Pixel Readout Electron multiplication is decoupled from electron collection: Allow flexible readout encoding methods Prevent discharge damage to the front-end electronics 7 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

8. Thick GEM (THGEM), Resistive THGEM 8 Fabricated by standard PCB technique drill one hole at a time (doesn’t scale well to large areas) Easily available to the masses Thickness ~ 1mm: ease of handling Thick copper, and optional resistive coating make THGEM spark resistant Further segmentation of the copper into strips: S-RETHGEM, greatly reduces the energy of HV discharges B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

9. MicroMesh Gaseous Structure (MicroMegas) 9 A layer of micromesh supported by 50-100µm insulating pillars over an anode plane Multiplication (up to 10 5 or more) takes place between the anode and the mesh and the charge is collected on the anode (one stage – similar to PPAC) Bulk MicroMegas uses standard PCB fabrication technique, enable large area detector fabrication with integrated readout electrodes. In a standard configuration, the front-end electronics are exposed to the high field region, vulnerable to discharge damage. Y.Giomataris, 1996 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

10. MicroMegas + Pixel Readout ASIC = Ingrid 10 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

11.  MicroDot (S. Biagi, 1995)  MIcro Pin Array (P. Rehak, 1999)   PIC (A.Ochi, T.Tanimori, 2001) Pin/Dot Type Avalanche Structures 11 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

12. Charge Particle Tracking – Time Projection Chamber – Planar and Cylindrical Trackers Photon Detection – Gaseous Photomultiplier – Cherekov Imaging Calorimeter – DHCAL @ ILC X-ray and Neutron Detection – X-ray Imaging: Spherical GEM – Polarimeter: GEM + pixel readout – Neutron Imaging: MSGC, Cascade Major Applications of MPGDs 12 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

13. Time Projection Chamber, T2K 13 First large size MPGD based TPCs J. Beucher, MPGD ‘09 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

14. MPGD Trackers 14 GEM Chamber Horse Shoe Card VFAT Hybrids 11 th Card Chamber coolingHV cables Coincidence Chips 3 mm 2 mm Cathod e GEM 1 GEM 2 GEM 3 Anode Read-out Cylindrical Triple GEM KLOE PANDA TPC TOTEM GEMs B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

15. STAR Forward GEM Tracker 15 CCD surface scanner to assess GEM foil quality CERN foil (inner hole diameter) Production of GEM foils – collaborative effort of Tech-Etch with BNL, MIT and Yale Tech-Etch (inner hole diameter) Systematic Tech-Etch and CERN GEM foil comparison: Blue – 6  m below average Red – 6  m above average B. Surrow et al., Proc. of the MPGD Conf., Crete, June 2009 D. K. Hasell, RD51 Collab. Meet., Nov.23-25, 2009, WG1 Meeting B.Surow B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

16. Phenix Hadron Blind Detector 16 Mesh CsI layer Triple GEM Readout Pads e-e- Primary ionization g HV Cherenkov blobs e+e+ e-e-  pair opening angle ~ 1 m Collection efficiency for photoelectrons and ionization Weizmann, BNL, Stony Brook… 1 st windowless Cherenkov detector CF 4 as both radiator and detector gas Hadron rejection factor up to 50 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

17. X-ray Polarimeter 17 Pixel size:300µm Electronics noise: 50e B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

18. Optical Imaging of the p/ 3 H Tracks with GEM F.A.F. Fraga et al, NIM. A478 (2002) 357 Use a CCD camera to record the scintillation light emitted from the GEM holes during the electron multiplication process. 18 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

19.  There is a upper limit on proportional mode of electron avalanche: 10 7 - 10 8 e Give up on building spark-free detectors? Build spark-resistant detector/electronics: a must for MicroMegas Optimize readout electronics to reduce noise, and gas gain  Need to understand the role of the insulators in the avalanche region of the detector Kapton in the hole of GEMs: charging effect, rate dependence of gain Pillars supporting the MicroMegas mesh  Impact of the positive ion space charge Multi-stage GEM or GEM/MicroMegas combination to reduce ion back flow More exotic additional amplification structures (MHSP) Gating with GEMs, wire planes Technical Challenges: Stability/Reliability 19 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

20. MicroMegas mesh currents in neutron beam 20 Atlas Muon MicroMegas R&D Standard MM: Large currents Large HV drops, recovery time O(1s) Chamber could not be operated stably Gas: Ar:CO 2 (85:15) Neutron flux: ≈ 1.5x10 6 n/cm 2 s With resistive strip protective layer B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

21. MPGDs provide avalanche granularity down to the hole pitch (~100µm for GEM, even smaller for MicroMegas), to achieve comparable position resolution, we need either fine grained readout electrodes (high electronic channel count /power /complexity) or clever interpolating readout, similar to what we did for the MWPCs. Development of low noise, low power, application specific readout electronics is a must. Technical Challenges: Optimized Position Readout 21 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

22. Technical Challenges: Electronics Interconnect 22 Anode pads ASICs High density interconnect traces with 0.006” width and spacing Gas tight construction: large number of blind vias Cylindrical geometry: no auto-routing of the traces Avoid digital activity interfere with low noise analog front end LEGS TPC (2006), first GEM based TPC designed and constructed for an experiment Integrated anode pads/ASIC board with 7296 channels, <10W power, ENC<250e Sub-assembly B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

23. The supply of GEM foil is largely sole source: CERN – Laser & plasma etching from Japan – Tech-Etch from US Misalignment of holes over large area GEM foils – Current GEM size limit: ~1mx0.5m – New signal mask process solves the alignment issue – Splicing techniques are being developed to join multiple foils Installation and handling requires cleanroom Environment – Particularly for MicroMegas based detectors – Glove-box with dry gas for CsI coated GEMs Technical Challenges: Availability 23 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

24. Participation of US institutions in MPGD R&D is low: 7 out of 73 in the RD51 collaboration list – Argonne National Laboratory – Brookhaven National Laboratory – Florida Institute of Technology – MIT – University of Arizona – University of Texas – University of Virginia Other Challenges 24 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

25.  RD51: http://rd51-public.web.cern.ch/RD51-Publichttp://rd51-public.web.cern.ch/RD51-Public  Activities: WG1 - Technological Aspects and Development of New Detector Structures WG2 - Common Characterization and Physics Issues WG3 - Applications WG4 - Simulations and Software Tools WG5 - MPGD Related Electronics WG6 - Production WG7 - Common Test Facilities A Very Active International Collaboration on MPGD Development 25 “RD51 aims at facilitating the development of advanced gas-avalanche detector technologies and associated electronic-readout systems, for applications in basic and applied research.” B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

26. Backup slides 26 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

27. 27 4/5/09 50  m Kapton 5  m Cu both sides Photoresist coating, masking and exposure to UV light Metal chemical etching Kapton chemical etching Second masking Metal etching and cleaning GEM Manufacturing Process B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

28. 28 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

29. Thick GEM Fabrication 29 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

30. 30 Read-out board 4 layers PCB Laminated photoimageable coverlay Frame Stainless steel mesh on frame mesh on frame Frame Exposure + development + cure + cut Easy manufacturing - Large size compatible - Low cost Robust and electrically testable at the production time The micro mesh consist of 18um μm thick stainless steel 400 Lpi woven microstrings. This micro mesh is embedded between two photoimageable coverlay layers with a micron precision (to define the amplification region) Micromegas Manufacturing Process I. Giomataris et al, NIM A560 (2006) 405 B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010

31. Manufacturing process of a polyimide- based μ-PIC (1) Form the inner pattern and laminating Etching the via pattern (2) (3) (4) (5) Laser drilling Via-fill plating Etching the cathode pattern Manufactured by Dai Nippon Printing B. Yu, Workshop on Detector R&D, FNAL, 7--9 Oct. 2010 31