13 Oct 2006Ageing Meeting Geneva, Niels & Gras1/15 NIKHEF update 3 lines of attack: 1)Heating (Mod 30) 3 days at 45 C, 4 days at 48 C Q1: Change in geometry, gas tightness, gain? Q2: Effect on ageing? 2)Flushing (Mod 2) Improves rapidly, but suddenly worse Q: why?? 3)HV training (Mod 3) Damage reappears after 200 hrs Q: 200hrs of irradiation, or time constant? Thanks to Edwin & Besma

13 Oct 2006Ageing Meeting Geneva, Niels & Gras2/15 Conclusions Bad news 1)Heating We can not confirm beneficial effect of heating 2)Flushing Effect of flushing is temporary! Due to opening of module?? Pollution? Oxygen? Humidity? 3)HV training It only seems to prevent ageing for subsequent 200 hrs of flushing Not completely understood: It cures and prevents ageing at irradiated spots Can it also prevent ageing on unirradiated spots?

13 Oct 2006Ageing Meeting Geneva, Niels & Gras3/15 1) Heating Mod 30 Setup

13 Oct 2006Ageing Meeting Geneva, Niels & Gras4/15 1) Heating Mod 30 Temperature: 1 st heating 3 days Procedure 1)Module 30 is heated while flushing with CO 2 2)One day at 35C 3)3 days at 48 C 4)4 days at 48 C Logbook 22-29SepMeasure dimension, gas tightness 29Sep35C1 day 29Sep-2 Oct48C3 days 2-4 OctMeasure dimension, gas tightness 4 OctFlush 24 hrs, then irradiate 6-10 Oct48C>4 days 10 OctMeasure dimension, gas tightness 10 OctFlush 24 hrs, then irradiate Sep29 Oct 2

13 Oct 2006Ageing Meeting Geneva, Niels & Gras5/15 1) Heating Mod 30 Temperature: 2 nd heating 4 days Procedure 1)Module 30 is heated while flushing with CO 2 2)One day at 35C 3)3 days at 48 C 4)4 days at 48 C Logbook 22-29SepMeasure dimension, gas tightness 29Sep35C1 day 29Sep-2 Oct48C3 days 2-4 OctMeasure dimension, gas tightness 4 OctFlush 24 hrs, then irradiate 6-10 Oct48C>4 days 10 OctMeasure dimension, gas tightness 10 OctFlush 24 hrs, then irradiate Oct 5 Oct 6

13 Oct 2006Ageing Meeting Geneva, Niels & Gras6/15 1) Heating Mod 30 Geometry: Flatness Flatness: Module is flat to +/- 200 μm Change after heating <100 μm Before After Row III II I

13 Oct 2006Ageing Meeting Geneva, Niels & Gras7/15 1) Heating Mod 30 Geometry: Length Length: Module shrinked by 1.03±0.10mm Module shrinked by additional 0.38±0.10mm  These shifts are easily seen by eye… DateabAverage (a+b)/2 Nominal: 2.46mm Delta 22Sep Sep Oct Oct Oct mm 8.0mm a b module table a+b/2

13 Oct 2006Ageing Meeting Geneva, Niels & Gras8/15 1) Heating Mod 30 Geometry: Width Width: Module shrinked by 100 μm +/- 50 μm

13 Oct 2006Ageing Meeting Geneva, Niels & Gras9/15 1) Heating Mod 30 Geometry: Shape Before After Consistency check of decreased width: ~ -100μm Shape: Straight within +/-100μm

13 Oct 2006Ageing Meeting Geneva, Niels & Gras10/15 1) Heating Mod 30 Gas Tightness Before 1 st heating 2 nd heating DateLeakage Flow (l/s) 22Sep Sep Oct Oct Oct Oct Gas tightness: OK, Unchanged: l/s ± l/s Corresponding to 0.007mb/min

13 Oct 2006Ageing Meeting Geneva, Niels & Gras11/15 1) Heating Mod 30 Ageing Sep 4, after 6 days of flushing Sep 19, after HV training Oct 4, after 3 days at 48 C Ageing: No sign of improvement after 3+4 days at 48 C! Module became very noisy?? Oct 11, after 3+4 days at 48 C Scan after Scan before

13 Oct 2006Ageing Meeting Geneva, Niels & Gras12/15 Conclusions: Module 30 follows initial pattern from mod 2 What happened with module 2 ??  Briefly opened when moved from setup to setup  Gas had finished before worsening of module 2  Flushing is only temporary benificial !?   similar for heating?? 2) Long term flushing Module m 3 Compare to result from Heidelberg: 100 days M002 ?!? Heating of M030!?

13 Oct 2006Ageing Meeting Geneva, Niels & Gras13/15 2) Long term flushing dips in Module 3? History:  21Mar – 12Apr:  28Mar-11Apr: opened module  15Apr – 23May:  25Apr-10May: played with water bottle  10May-15May: module not connected  23May – 19Jun:  6Jun: Change Ar bottle  6Jun – 19 Jun: Addition of O 2  19Jun-15Aug  20Jun-14Jul: module not connected ModDateLocI(nA)Time (hrs) 13B18Jancleanroom B23FebLab B21MarLab B12AprLab A15AprLab A23MayLab A19JunLab A15AugLab Mar: opened module during 14days 10May: opened module during 5days 6Jun: flushed with 4% O 2 for 13days 20Jun: opened module during 24days

13 Oct 2006Ageing Meeting Geneva, Niels & Gras14/15 3) HV training Gas flow Conditions:  Flow: Ar/CO 2 70/30, 20 l/hr  Irradiation: 2mCu, 90 Sr source  Sequence: 1)HV training ~40 hrs 1870 and 1920V 2)Irradiate 340 hrs 3)HV training 18 hrs 1910 V Conclusions:  A second HV training helps again 340 hrs After HV Lower? 2 nd HV training1 st HV training NB: 700 hrs ~ s ~ 3 months nominal LHC hrs Rel.gain 3 rd HV training Lower??

13 Oct 2006Ageing Meeting Geneva, Niels & Gras15/15 3) HV training Question: 1)Does it prevent ageing during 200 hrs of irradiation 2)Or does it prevent ageing for 200 hrs of flushing…  It looks like 1)  But untrained part improves!? 2 nd HV training1 st HV training3 rd HV training 8 days of flushing 3 days of flushing ?? Gain indeed went up Ratio 10Oct/3 Oct: 3Oct 29Sep -3Oct 10Oct

13 Oct 2006Ageing Meeting Geneva, Niels & Gras16/15 3) HV training Question: Is ageing also prevented at previously unirradiated spots (pos. 190cm) ?  Marginally… This seems in contradiction with measurements of Aug 20 on unirradiated spot (pos. 200cm) 20hrs 96hrs Deepest point Integrated loss over surface

13 Oct 2006Ageing Meeting Geneva, Niels & Gras17/15 Conclusions Bad news 1)Heating We can not confirm beneficial effect of heating 2)Flushing Effect of flushing is temporary! Due to opening of module?? Pollution? Oxygen? Humidity? 3)HV training Not completely understood: It cures and prevents ageing at irradiated spots Can it also prevent ageing on unirradiated spots?? –Contradicting results…