1. AGEING STUDIES Material tests update Ageing tests with Methane – Extrapolation to ALICE conditions – Extrapolation to STAR conditions C. Garabatos, GSI

2. TPC C.M. 2-3.06.03C. Garabatos, GSI Darmstadt2 Tested materials MaterialS/F (h/cm)mC/cmResult Tedlar 1 (*)0.33.2OK Araldit 20130.0113OK Araldit DP1900.359OK Araldit 20120.355.8OK Araldit 1160.359OK Tedlar 2 (*)2.24.3OK (*) ALICE: 34 h/cm

3. TPC C.M. 2-3.06.03C. Garabatos, GSI Darmstadt3

4. TPC C.M. 2-3.06.03C. Garabatos, GSI Darmstadt4 Ne-CO 2 [90-10] Gain ~ 24 000

5. TPC C.M. 2-3.06.03C. Garabatos, GSI Darmstadt5 Gain with P10

6. TPC C.M. 2-3.06.03C. Garabatos, GSI Darmstadt6 First ageing test: ended with Malter breakdown

7. TPC C.M. 2-3.06.03C. Garabatos, GSI Darmstadt7 Second ageing test: ended with Malter breakdown

8. TPC C.M. 2-3.06.03C. Garabatos, GSI Darmstadt8 Characterization of the Rate of ageing

9. TPC C.M. 2-3.06.03C. Garabatos, GSI Darmstadt9 Rate of ageing in ALICE with P10

10. TPC C.M. 2-3.06.03C. Garabatos, GSI Darmstadt10 Estimation of rates and doses BOEdN/dYSec. track length (cm) wire length (cm) # of wires wire pitch (cm) Ne (cm -1 )Gain Trig. rate (Hz) ALICE 8000x2163606560.254520000200+40 STAR 650x2150653000.485400020 Method charge density (C) current (nA/cm) dose (mC/cm) ALICE Marek Max. (TDR) 0.5  10 -12 /20cm 1.010 in 10 yr ALICE Marek Sector 3.0  10 -12 /sector 0.373.7 in 10 yr ALICE BOE Sector 1.0  10 -12 /sector 0.131.3 in 10 yr STAR BOE Sector.0002  10 -2 /sector 0.0009*.035* in 3 months * Scale by factor 5

11. TPC C.M. 2-3.06.03C. Garabatos, GSI Darmstadt11 Ageing predictions

12. TPC C.M. 2-3.06.03C. Garabatos, GSI Darmstadt12 Conclusions Materials tested so far are most probably fine for the ALICE TPC  Methane is out of the question  It produces severe ageing well within the time scale of ALICE  IROCs would breakdown in the first year  Methane is a safety nightmare  Next test: Vacuum grease for O-rings