First TRD Production Chambers

1. First TRD Production Chambers Production Tests Results Documentation TRD Collaboration meeting GSI Clemens Adler

2. Nov/Dec: Vist from Oleg and Sasha (Dubna): Parallel production of 2 chambers at Heidelberg Test of chambers: Christmas 2003-January 2004 New(s) (Challenges): -Glueing of Padplane-panel-assembly (100 cables have to be fed trough holes) -Wacosit Profile extruded in final shape (easier to use than standard G10 parts) -Winding machine after modifications Production of first Chambers TRD Collaboration meeting GSI Clemens Adler

3. Feeding cables trough Backpanel cutouts worked well Glueing of Padplane to Honeycomb works, but can still be improved Padplane glueing TRD Collaboration meeting GSI Clemens Adler

4. Wacosit is behaving good, minor quality improvements are discussed with Manufacturer Wacosit profiles TRD Collaboration meeting GSI Clemens Adler

5. Oleg glueing Anode wires Wiring TRD Collaboration meeting GSI Clemens Adler

6. All current materials behave well. Tooling needed: Positioning of wire ledges, Distance ledges Crane for lifting of winding frame (installed in January) New winding frames (arrived) What we learned: TRD Collaboration meeting GSI Clemens Adler

7. Dark current: (Was a Problem with Prototype chambers) At first dark current started at ~1400-1500V. After some conditioning (over night at <50 nA) Dark Currents <1 nA Leak Rate Xe-cost driven Gain uniformity Electronics driven Tests TRD Collaboration meeting GSI Clemens Adler

8. Grounding of Padplane: Adhesive copper tape: not reliable Foldback clips, w. conductive foam: Complicated to use ->use of PCB with real connectors to ensure reliable grounding of Padpane while testing (in devel.) Gas filling: Issue: time Procedure: flush Chamber with 80-100 l/h Ar/CO2 with open Gas-in-outlets. 1000 ppm O2 level after 2-3 h. Connect outlet etc. and flush at 20 l/h overnight ->few ppm level next morning Preparation for tests TRD Collaboration meeting GSI Clemens Adler

9. Left: copper tape grounding Below: foldback clips grounding Gain Uniformity Chamber1 Low areas where foldback clip was not connected to ground Gain uniformity <+-10% TRD Collaboration meeting GSI Clemens Adler

10. Looks „flat“ Source collimation is not sufficient for detailed study ->X-Ray test stand should give better results Gain Uniformity Chamber 2 TRD Collaboration meeting GSI Clemens Adler

11. Determined by measureing O2 concentration (and assuming diffusion leaks) Upper limit: 1,5-3 mbar*l/h Test chamber performance: <0,5 mbar*l/h (last year chamber: <0,2 mbar*l/h, with greased gas inlets) Leak rate TRD Collaboration meeting GSI Clemens Adler

12. Solution: Check that gas exits chamber down to low flow rates (1l/h). But: 1 l/h leak diffusion dominated? ->O2 conc. method fails Use sniffer to detect leaks ??? Problem:very large leaks (some l/h) will also show „reasonable“ leak rates (<3mbar*l/h) with O2 method. Leak rate cont. I TRD Collaboration meeting GSI Clemens Adler

13. Leakage of two connected chambers: Sniffer could detect leaks at gas connections. ->grease should be used to improve leak rate Leak rate cont. II TRD Collaboration meeting GSI Clemens Adler

14. Leak Rate: upper limit: 1 mbar*l/h Gain Uniformity: ±15% limit (electronics limited) Test parameter suggestions • Absolute Gain • Reasonable goal: • <0,5 mbar*l/h. • Higher leak rates can be detected with a sniffer • Reasonable goal: • <± 10% ? • Currently limited by the source. • (pressure dependant) Common Set of expected anode current values at defined parameters (Anode-,Drift- voltage) TRD Collaboration meeting GSI Clemens Adler

15. Documentation of common standards • Chamber building HowTo needed • Information is mostly there. Format? • Document with all Dimensions and allowable tolerances • Document with Test limits (somewhat more explicit than in this presentation) TRD Collaboration meeting GSI Clemens Adler