The Bigbite second GEM tracker

SBS GEM Trackers Front Tracker Geometry x6 18 modules In Italy  50 cm x 40 cm Modules are assembled to form larger chambers with different sizes  Front tracker: Six 40 cm x 150 cm GEM layers  INFN Funding: to be built in Italy  Polarimeter trackers: Eight 50 cm x 200 cm GEM layers  to be built in Virginia 76 modules In Virginia Collaboration: INFN (Roma, Genova, Catania, Bari) and UVa SBS GEM trackers will form the largest area GEM tracker in the world

 Fabricate 29 GEM modules by Oct  Assemble and test at least one 50 cm x 200 cm GEM layer ( 5 modules) for Bigbite.  Our plan is to build 12 (of the 29) SBS modules and instrument them with APV electronics in  So it will be possible to assemble two back GEM layers for BB in time for A1n.  All costs are budgeted into SBS WBS 2; no extra cost to A1n.  Graduate students from UVa for installation and commissioning. 3 UVa component of SBS WBS 2 (Neutron FF)

 A 3.5 m x 3 m level-1000 clean-room at UVa  Clean room in a 4 m x 10 m semi-clean (1000 level) area.  Equipment to build 40 cm x 50 cm SBS modules:  GEM foil stretcher, with tension monitoring  Dry N2 HV box, with picoammeter, for testing GEM foils  Large ultra-sonic bath for cleaning frames  APV 25 readout system developed in Italy, going into production now  Two APV25 based readout systems with 5000 channels for testing GEMs: these systems being incorporated into CODA now.  Wiener MPOD High Voltage system with 16 sensitive HV channels  GEM chamber prototyping  INFN and UVa groups have built and tested seven 10 cm x 10 cm prototypes  40 cm x 50 cm module design complete, has been optimized with two prototypes.  Two 40 x 50 cm prototypes built in Italy, two more at UVa. 4 Preparations for the SBS GEM project

Prototype GEM tracker tests and results 5 10 cm x 10 cm prototype GEM tracker preared to go into hall A 70  m position resolution Charge deposition correlation between x and y stripes

GEM module construction status at UVa 6  All parts for 2 chambers now at hand:  Readout planes arrived 2 weeks ago. – 1 Rome type + 2 Uva type  Spent about 2 months developing techniques for GEM assembly  Used test frames and foils  Final procedure well established now.  Final assembly of the first chamber (Uva type) this week and next week  Readout and 2 GEMs already glued and tested.  1 more GEM, Cathode and gas window by early next week.  Finish assembly by end of next week. SBS readout ( E.Cisbani, INFN Italy) New design (K. Gnanvo. Uva) Panasonic connectorsZIF connectors

GEM module construction status at UVa 7 New 40 cm x 50 cm GEM stretcher at Uva GEM foil and Frame HV test box Fully equipped INFN 40x50 cm 2 GEM module for a beam test at DESY Clean room at UVa

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\ 8 New 40 cm x 50 cm GEM stretcher at Uva

9 Test frames glued

GEM R&D and assembly facility at UVa 10 GEM foil and Frame HV test box: - check for curent (sector current < 5 nA) and sector capacitance.The 3 foils tested so far have been good. Test foils were bad (higher currents)

GEM R&D and assembly facility at UVa 11

GEM R&D and assembly facility at UVa 12

K. Gnanvo - SoLID Coll. Meeting, 02/03/12 Page 13