Uva GEM R&D Update –Part I Kondo Gnanvo, Nilanga Liyanage, Vladimir Nelyubin, Kiadtisak Saenboonruang, Taylor Scholz and Adarsh Ramakrishnan In Collaboration with Evaristo Cisbani and Paolo Musico

Outline  GEM R&D and assembly facilities at UVa  Cosmic test results  Update on the 40 × 50 cm 2 GEM prototype 2

GEM R&D and assembly facility at UVa  A 3.5 × 3 m 2 class 1000 clean room  Used for the assembly of BigBite drift chambers and GEM tracker with 10 × 10 cm 2 chambers  Located in a large (4.5 m x 9 m) semi-clean area.  Accessories (clean room table, HV Gas box,….  Additional clean room to be added later this year  Setting up the GEM UVa  the test and commissioning of the chambers  16 channels Wiener HV power supply (VME)  Picoammeter model Keithley 6487  CODA based DAQ  2 APV readout systems 3

GEM R&D and assembly facility at UVa  The mechanical stretcher  Use for stretching GEM foil and glue it to spacer frames to keep it flat  Stretch the foil to a tension bigger than 1kg/cm  Method developed by Bencivenni. Et al. (LNF Italy) for LHCb GEM chambers\ 4 New 40 cm x 50 cm GEM stretcher at Uva More detail in Kondo’s talk next week

Page 5 More detail in Kondo’s talk next week

6 Test frames glued More detail in Kondo’s talk next week

GEM R&D and assembly facility at UVa 7 GEM foil and Frame HV test box More detail in Kondo’s talk next week

GEM R&D and assembly facility at UVa 8 More detail in Kondo’s talk next week

GEM R&D and assembly facility at UVa 9 More detail in Kondo’s talk next week

GEM R&D and assembly facility at UVa 10 GEM foil and Frame HV test box More detail in Kondo’s talk next week

On going studies with 10 cm x 10 cm chambers  compact voltage dividers from CERN  Gains, spark rates etc. well studied for this combination of resistors  Nominal operation at 4100 V, but tested to 4300 V (Max voltage on a GEM foil is 430 V; this is small compared to 500 V foil test voltage)  If there a spark in the bottom GEM,  V for other GEMs increase by only about 6 V. A spark in the other foils has negligible effect. 11 GEM 1:  V = 410 V GEM 2:  V = 373 V GEM 2:  V = 328 V = 4100 V

CMS Prototype Gain measurements with the divider K. Gnanvo - SoLID Coll. Meeting, 02/03/12 Page 12

CMS Prototype Gain measurements with the divider K. Gnanvo - SoLID Coll. Meeting, 02/03/12 Page 13

GEM R&D and assembly facility at UVa 14  10 × 10 cm 2 GEM prototypes  3 working chambers for the tracker,  2 mores to be assembled soon  trigger GEM chamber with pad readout  Scalable Readout System (SRS)  Multi channel scalable readout system developed by the CERN-based RD51 coll.  Small UVa with up to 2048 ch  4 small GEM chambers with X/Y readout  Currently running with a standalone ALICE DAQ (DATE) and Monitoring (AMORE) software.  Integration of the SRS into CODA under development

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