NIKHEF update

1
NIKHEF update

• 3 lines of attack
• Heating (Mod 30)
• 3 days at 45 C, 4 days at 48 C
• Q1 Change in geometry, gas tightness, gain?
• Q2 Effect on ageing?
• Flushing (Mod 2)
• Improves rapidly, but suddenly worse
• Q why??
• HV training (Mod 3)
• Damage reappears after 200 hrs
• Q 200hrs of irradiation, or time constant?

Thanks to Edwin Besma
2
Conclusions

• Bad news
• Heating
• We can not confirm beneficial effect of heating
• Flushing
• Effect of flushing is temporary!
• Due to opening of module??
• Pollution? Oxygen? Humidity?
• 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?

3
1) Heating Mod 30Setup
4
1) Heating Mod 30Temperature 1st heating 3 days

• Procedure
• Module 30 is heated while flushing with CO2
• One day at 35C
• 3 days at 48 C
• 4 days at 48 C

Sep29
Logbook Logbook Logbook
22-29Sep Measure dimension, gas tightness Measure dimension, gas tightness
29Sep 35C 1 day
29Sep-2 Oct 48C 3 days
2-4 Oct Measure dimension, gas tightness Measure dimension, gas tightness
4 Oct Flush 24 hrs, then irradiate Flush 24 hrs, then irradiate
6-10 Oct 48C gt4 days
10 Oct Measure dimension, gas tightness Measure dimension, gas tightness
10 Oct Flush 24 hrs, then irradiate Flush 24 hrs, then irradiate
Oct 2
5
1) Heating Mod 30Temperature 2nd heating 4 days
Oct 5

• Procedure
• Module 30 is heated while flushing with CO2
• One day at 35C
• 3 days at 48 C
• 4 days at 48 C

Logbook Logbook Logbook
22-29Sep Measure dimension, gas tightness Measure dimension, gas tightness
29Sep 35C 1 day
29Sep-2 Oct 48C 3 days
2-4 Oct Measure dimension, gas tightness Measure dimension, gas tightness
4 Oct Flush 24 hrs, then irradiate Flush 24 hrs, then irradiate
6-10 Oct 48C gt4 days
10 Oct Measure dimension, gas tightness Measure dimension, gas tightness
10 Oct Flush 24 hrs, then irradiate Flush 24 hrs, then irradiate
Oct 6
6
1) Heating Mod 30Geometry Flatness

• Flatness
• Module is flat to /- 200 µm
• Change after heating lt100 µm

Row III II I
Before
After
7
1) Heating Mod 30Geometry Length
Date a b Average (ab)/2 Nominal 2.46mm Delta
22Sep 3.69 2.88 3.28 0.82
25Sep 3.55 3.21 3.38 0.92
3 Oct 2.74 2.03 2.38 -0.08
5 Oct 2.27 2.16 2.21 -0.25
10 Oct 2.30 1.55 1.92 -0.54
12.92mm
module
8.0mm
table
ab/2

• Length
• Module shrinked by 1.030.10mm
• Module shrinked by additional 0.380.10mm
• These shifts are easily seen by eye

8
1) Heating Mod 30Geometry Width

• Width
• Module shrinked by 100 µm /- 50 µm

9
1) Heating Mod 30Geometry Shape
Before

• Shape
• Straight within /-100µm

After
Consistency check of decreased width -100µm
10
1) Heating Mod 30Gas Tightness
Before
Date Leakage Flow (l/s)
22Sep 1.5 10-5
25Sep 1.1 10-5
3 Oct 2.8 10-5
5 Oct 0.4 10-5
10 Oct 4.0 10-5
10 Oct 1.8 10-5
1st heating
2nd heating

• Gas tightness
• OK, Unchanged 1.5 10-5 l/s
• 1.5 10-5 l/s
• Corresponding to 0.007mb/min

11
1) Heating Mod 30Ageing
Sep 4, after 6 days of flushing

• Ageing
• No sign of improvement after 34 days at 48 C!
• Module became very noisy??

Sep 19, after HV training
Oct 4, after 3 days at 48 C
Scan after
Scan before
Oct 11, after 34 days at 48 C
12
2) Long term flushing

• 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??

Compare to result from Heidelberg
Module 63
M002 ?!?
36.2 m3
Heating of M030!?
100 days
13
2) Long term flushingdips in Module 3?
Mod Date Loc I(nA) Time (hrs)
1 3B 18Jan cleanroom 190 15
2 3B 23Feb Lab 150 15
3 3B 21Mar Lab 150 21.5
4 3B 12Apr Lab 150 15
5 3A 15Apr Lab 180 23
6 3A 23May Lab 140 22
7 3A 19Jun Lab 150 16
8 3A 15Aug Lab 150 20

• 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 O2
• 19Jun-15Aug
• 20Jun-14Jul module not connected

14
3) HV training
Gas flow

• Conditions
• Flow Ar/CO2 70/30, 20 l/hr
• Irradiation 2mCu, 90Sr source
• Sequence
• HV training 40 hrs 1870 and 1920V
• Irradiate 340 hrs
• HV training 18 hrs 1910 V
• Conclusions
• A second HV training helps again

340 hrs
Lower?
After HV
Rel.gain
340350 hrs
Lower??
After HV
NB 700 hrs 2.5 106 s 3 months nominal LHC
15
3) HV training

• Question
• Does it prevent ageing during 200 hrs of
  irradiation
• Or does it prevent ageing for 200 hrs of
  flushing
• It looks like 1)
• But untrained part improves!?

8 days of flushing
3 days of flushing
29Sep -3Oct
3Oct
10Oct
??
Gain indeed went up Ratio 10Oct/3 Oct
16
3) HV training
20hrs

• 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)

96hrs
Deepest point
Integrated loss over surface
17
Conclusions

• Bad news
• Heating
• We can not confirm beneficial effect of heating
• Flushing
• Effect of flushing is temporary!
• Due to opening of module??
• Pollution? Oxygen? Humidity?
• HV training
• Not completely understood
• It cures and prevents ageing at irradiated spots
• Can it also prevent ageing on unirradiated
  spots??
• Contradicting results