Ageing studies the miracle
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Ageing studies: the Miracle. HV training. Irradiation after brief HV training. Conditions: Flow: Ar/CO 2 70/30 2mCu, 90 Sr source HV training at 1850 V for ~1 hour, only for upper half (channels 33-64 in the plots) ~1 μ A / wire for 1 hour Conclusions:

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Ageing studies: the Miracle

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Ageing studies the miracle

Ageing studies: the Miracle

HV training


Ageing studies the miracle

Irradiation after brief HV training

  • Conditions:

  • Flow: Ar/CO2 70/30

  • 2mCu, 90Sr source

  • HV training at 1850 V for ~1 hour,

    • only for upper half (channels 33-64 in the plots)

    • ~1 μA / wire for 1 hour

      Conclusions:

  • Smaller damage at trained half?

Ratio of scans from Aug17 / Aug16

Ch 33-64 HV trained at 1850V

Gas flow


Non gentle extended hv training

“Non-gentle” extended HV training

  • Procedure:

  • Only half the module is put under HV, to keep a reference

  • IV-curve for positive bias, without irradiation

  • HV training/processing for 20 hrs

Current per wire per cm:

Similar to current during irradiation


Large recovery after hv training 1

Large recovery after HV training (1)

Ch 33-64

trained at 1870V

After HV training

Before HV training

What is this??

Lower gain in trained area?

Ratio


Large recovery after hv training 2

Large recovery after HV training (2)

Some spots are fully recovered, other spots are not recovered at all

Not

trained

Trained

No recovery

at all??

Recovery


Large recovery after hv training 3

Large recovery after HV training (3)

Some spots are fully recovered, other spots are not recovered at all

Not

trained

Trained


Large recovery after hv training 4 zoom in

Large recovery after HV training (4) Zoom in

What is the small increase in gain

in the untrained region (ch29-32) ?

 Possibly artificial effect from current meter:

region with very large damage, so small current

variation is large fractional difference


Hv training prevents ageing

HV training prevents ageing!

No damage in trained region!!

(A bit of extra gain loss in

previously heavily irradiated spot?)


Conclusions non gentle extended hv training

Conclusions“Non-gentle” extended HV training

HV training

  • HV training

  • Half module for 20 hrs at 1870V without irradiation

  • Conclusions

  • Large recovery of damaged area after 20 hrs at 1870V

  • Not all damaged area recovered

  • Small, uniform, gain decrease over full half-module area

  • HV training prevents ageing

Damage of some wires disappear:


Hv training 1910v

HV training 1910V

  • Procedure:

  • Only half the module is put under HV, to keep a reference

  • IV-curve for positive bias, without irradiation

  • HV training/processing for 20 hrs


Full recovery after hv training at 1910v

Full recovery after HV training at 1910V

Ch 33-64

trained at 1910V

After 2nd HV training

Before 2nd HV training

What is this??

Lower gain in trained area?

Ratio


Full recovery after hv training at 1910v1

Full recovery after HV training at 1910V

Finally, *all* spots recovered!

Not

trained

Trained


Hv training prevents ageing1

HV training prevents ageing!

No damage in trained region!!

What is this??

Higher gain in trained area?

What happens

with ch21 – ch32?

(A bit of extra gain loss in

previously heavily irradiated spot?)


Iv curves with pos and neg bias

IV curves withpos and neg bias

17 Aug, first try

  • Conditions:

  • Flow: Ar/CO2 70/30, 20 l/hr

  • No irradiation

  • 32 channels of module 3A

  • Measure total current of 32 channels using the CAEN power supply

    Conclusions:

  • Normal, pos, bias shows dropping current, indicating some processing

19 Aug, after training at 1870V

21 Aug, negative bias


Hv training prevents ageing irradiate longer

HV training prevents ageing: irradiate longer…

Gas flow

20 hrs

  • Conditions:

  • Flow: Ar/CO2 70/30, 20 l/hr

  • Irradiation: 2mCu, 90Sr source

  • After HV training procedure ch33-64

    • 20 hrs at 1870 V

    • 20 hrs at 1910 V

      Conclusions:

  • Trained wires show small gain drop

179 hrs

HV trained

292 hrs

340 hrs


Hv training prevents ageing irradiate longer1

HV training prevents ageing: irradiate longer…

  • Conditions:

  • Flow: Ar/CO2 70/30, 20 l/hr

  • Irradiation: 2mCu, 90Sr source

  • After HV training procedure ch33-64

    • 20 hrs at 1870 V

    • 20 hrs at 1910 V

      Conclusions:

  • Trained wires show smaller gain drop

Zoom scale:

HV trained

Gas flow

292 hrs


Hv training prevents ageing compare the 2 halves

HV training prevents ageing:compare the 2 halves


Hv training slows down ageing 1d plots

HV training slows down ageing (1d-plots)

Not

trained

Trained


Repair damage again

Repair damage AGAIN

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

180 hrs

340 hrs

Lower?

1st HV training

After HV

2nd HV training

NB: 400 hrs ~ 1.5 106 s

~ 2 months nominal LHC

340+70 hrs


Flat gold surface prevents 2co o 2 2co 2 hence keeps o 2

Flat Gold Surface prevents 2CO+O22CO2, hence keeps O2?

  • “It can act as a catalyst and transform carbon monoxide (CO) to carbon dioxide (CO2) when it comes in the form of tiny pieces, called nano-particles.” (http://www.physorg.com/news70200836.html)

  • “Particles of gold have been reported to be very active in various oxidation reactions. The particle size greatly influences the catalytic activity of gold particles and with decreasing particle size, the activity increases.” (http://idw-online.de/pages/de/news165204)


Hv training 2 nd module mod30b

HV training 2nd module (mod30B)

HV training, at 1870V

HV training, at 1930V


Hv trainings in mod 30b

HV trainings in Mod 30B

Big spot cured

Big spot cured,

small spot not

Still not


Confirm procedure mod 30b

Confirm procedure: Mod 30B

3a) 20 hrs, 20mCu

1) 20 hrs, 20mCu

3b) 63 hrs, 20mCu

This damage is

no peanuts…

2) After HV

4) After HV

  • Irradiation: 20mCu, 90Sr slit source

  • Sequence:

    • Irradiate 20 hrs

    • HV training 1870V (5hr)+1930V (14hr)

    • Irradiate 63 hrs

    • HV training 1950V (16hr)+1930V (16hr)

    • Irradiate x hrs

      Conclusions:

  • Trained wires show small gain drop

5) re-irradiate:

86 hrs, 20 mCu


Re apperance of damage

Re-apperance of Damage

  • 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 1910V

    • Irradiate 340 hrs

      Conclusions:

  • Damage reappears similarly the 2nd time

  • Max damage ~10% 250hrs after HV


Recap damage vs intensity

Recap: Damage vs Intensity

 Max damage at 5-10 nA


Repair damage again1

Repair damage AGAIN

1st HV training

2nd HV training

3rd 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

340+350 hrs

Lower??

NB: 700 hrs ~ 2.5 106 s

~ 4 months nominal LHC

After HV


In the meanwhile study long term flushing

In the Meanwhile:Study 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

???

Compare to result from Heidelberg:

Module 63

36.2 m3

100 days


Damage vs time module 3

Damage vs Time(module 3)

20Jun: opened module

during 24days

6Jun: flushed with

4% O2 for 13days

10May: opened module

during 5days

28Mar: opened module

during 14days

  • 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


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