HEC strange signals 1 09 Feb 2012 E.Ladygin Status of HEC spikes study in Protvino E.Ladygin,...

HEC strange signalsHEC strange signals 1109 Feb 2012 E.Ladygin09 Feb 2012 E.Ladygin

Status of HEC spikes Status of HEC spikes

study in Protvinostudy in Protvino

E.Ladygin, M.Kazarinov, E.Ladygin, M.Kazarinov, A.KozelovA.Kozelov

09 Feb 2012 E.Ladygi09 Feb 2012 E.Ladyginn

HEC strange signalsHEC strange signals 22

Setup parameters:Setup parameters:

– ADC frequency = 250MHzADC frequency = 250MHz– Amplifier input impedance = 50 OhmAmplifier input impedance = 50 Ohm– Gain of amplifier = 50 V/VGain of amplifier = 50 V/V– Trigger threshold of ADC = 39mVTrigger threshold of ADC = 39mV– Threshold recalculated to input = Threshold recalculated to input =

15.6uA15.6uA



Tests are done:Tests are done:

• test of Pad Board with new HEC hexcel test of Pad Board with new HEC hexcel mat, which was keeping in good conditions mat, which was keeping in good conditions at Dubna (Runs 188-193)at Dubna (Runs 188-193)

• test of new HEC hexcel mat between two test of new HEC hexcel mat between two copper plates (Runs 197-199)copper plates (Runs 197-199)

• test of Pad Board between two new HEC test of Pad Board between two new HEC hexcel mats in vacuum camera hexcel mats in vacuum camera ((pumping pumping without bakingwithout baking)) : :– Run 203 ->1 step (before pumping)Run 203 ->1 step (before pumping)– Run 205 ->2 step (short pumping ~30min)Run 205 ->2 step (short pumping ~30min)– Run 207 ->3 step (pumping ~24 h)Run 207 ->3 step (pumping ~24 h)– Run 208 ->4 step (pumping ~24+18 h)Run 208 ->4 step (pumping ~24+18 h)– Run 209 ->5 step (pumping ~24+18+19 h)Run 209 ->5 step (pumping ~24+18+19 h)



Signals in time (Runs 188-193) Signals in time (Runs 188-193) (humidity=~30-40%, estimated, not (humidity=~30-40%, estimated, not

measured)measured)

Pad Board with new hexcel matPad Board with new hexcel mat

0 100 200 300 400 500Time, h

-1000

-800

-600

-400

-200

0

A,

mV



Signals frequency (Runs 188-193) Signals frequency (Runs 188-193)


0 100 200 300 400 500

Time, h

0.0000

0.0001

0.0010

0.0100

0.1000

1.0000

10.0000

Freq, Hz



Signals amplitude (Runs 188-193) Signals amplitude (Runs 188-193)


-1000 -750 -500 -250 0

Amp, mV

0

50

100

150

200

250

Two peaks



Setup (Runs 197-199) Setup (Runs 197-199) (humidity=~20%, still not measured)(humidity=~20%, still not measured)

Hexcel mat between copper platesHexcel mat between copper plates

Teflon 5mm

Hexcel

Metal support

Copper pad

Copper pad

HV

Gain=50

50



Signals in time (Runs 197-199)Signals in time (Runs 197-199)


0 50 100 150 200Time, hour

0

200

400

600

800

A, mV

Stop run in 3 hours

Five negative pulses with ~ an hour time step

???My full

misunderstanding



Signals frequency (Runs 197-199) Signals frequency (Runs 197-199)


5 30 55 80 105 130 155 180

Time, h

0.00001

0.00010

0.00100

0.01000

0.10000

1.00000

Freq, Hz



Signals amplitude (Runs 197-199)Signals amplitude (Runs 197-199)


-100 0 100 200 300 400 500 600 700 800 900

Ampl, mV

0.0

0.5

1.0

1.5

2.0

2.5

3.0



Pad Board between two HEC Pad Board between two HEC hexcel mats in vacuum camerahexcel mats in vacuum camera

• In order to see signals from beginning and In order to see signals from beginning and behaviourbehaviour during removing during removing water/humidity was decided to put water water/humidity was decided to put water to hexcel (few seconds in water steam) to hexcel (few seconds in water steam)

• Study of signals during pumping was not Study of signals during pumping was not possible in my setup because HV trips possible in my setup because HV trips appear appear

• Therefore : pumping -> filling by nitrogen Therefore : pumping -> filling by nitrogen -> measuring -> pumping ….-> measuring -> pumping ….



Setup Setup

Vacuum camera

Amplifier

LV PS

HV PS



Pad Board between two HEC hexcel mats in Pad Board between two HEC hexcel mats in vacuum camera vacuum camera (1 step: before pumping )(1 step: before pumping )

Signals in time (Run 203) Signals in time (Run 203)

0 6 12 18 24Time, hour

-2000

-1600

-1200

-800

-400

0

400A, mV

Few positive pulses at the

beginning




Frequency (Run 203) Frequency (Run 203)

0 5 10 15 20Time, h

0.001

0.010

0.100

1.000

10.000

Freq, Hz

Time gap

~30min (???)




Amplitudes (Run 203) Amplitudes (Run 203)

-2000 -1500 -1000 -500 0

Ampl, mV

0

50

100

150

200

250No peaks



Pad Board between two HEC hexcel mats in Pad Board between two HEC hexcel mats in vacuum camera vacuum camera (2 step: 3 times short (2 step: 3 times short

pumping-filling by N )pumping-filling by N )

Signal in time (Run 205) Signal in time (Run 205)

0.0 0.8 1.6 2.4 3.2Time, hour

-800

-600

-400

-200

0

200A, mV

1 positive

signal





Examples of signals (run 205) Examples of signals (run 205)

# event

A, mV

More examples see in add slidesMore examples see in add slides





Frequency (Run 205) Frequency (Run 205)

0.0 0.5 1.0 1.5 2.0 2.5Time, h

0.0001

0.0010

0.0100

0.1000

1.0000

10.0000

100.0000

Freq, Hz





Amplitude (Run 205) Amplitude (Run 205)

-2000 -1500 -1000 -500 0

Ampl, mV

0

10

20

30

40

50



0.0 1.5 3.0 4.5 6.0Time, hour

-1500

-1200

-900

-600

-300

0

A, mV

Pad Board between two HEC hexcel mats in Pad Board between two HEC hexcel mats in vacuum camera vacuum camera (3 step: long time pumping (3 step: long time pumping

~24h )~24h )Signals , amplitude , frequency Signals , amplitude , frequency

(run207)(run207)

-2000 -1600 -1200 -800 -400 0

Ampl, mV

0

2

4

6

8

0 1 2 3 4 5Time, h

0.0001

0.0010

0.0100

0.1000

1.0000

10.0000

100.0000

Freq, Hz



Pad Board between two HEC hexcel mats in Pad Board between two HEC hexcel mats in vacuum camera vacuum camera (4 step: pumping ~24+18 h )(4 step: pumping ~24+18 h )

Signals , amplitude , frequency Signals , amplitude , frequency (run208)(run208)

0 20 40 60 80Time, hour

-2000

-1600

-1200

-800

-400

0

A, mV

-2000 -1600 -1200 -800 -400 0

Ampl, mV

0

5

10

15

10 30 50 70Time, h

0.00001

0.00010

0.00100

0.01000

0.10000

1.00000

10.00000

Freq, Hz



Pad Board between two HEC hexcel mats in Pad Board between two HEC hexcel mats in vacuum camera vacuum camera (5 step: pumping ~24+18+19 (5 step: pumping ~24+18+19

h )h )Signals , amplitude , frequency Signals , amplitude , frequency

(Run 209 is ongoing)(Run 209 is ongoing)

• Frequency :– 11 events in 0- 24 h– 2 events in 24 - 48 h– 1 event in 48 - 72 h

0 20 40 60 80Time, hour

-2000

-1600

-1200

-800

-400

0

A, mV

-2000 -1500 -1000 -500 0

Ampl, mV

0.0

0.5

1.0

1.5

2.0

2.5

3.0

10 30 50 70Time, h

10-006

10-005

10-004

10-003

10-002

10-001

Freq, Hz



Pad Board between two HEC hexcel Pad Board between two HEC hexcel mats in vacuum cameramats in vacuum camera

Median frequency (Freq) in runs vs Median frequency (Freq) in runs vs vacuum time (Tv)vacuum time (Tv)

0 10 20 30 40 50 60

Tv, h

1e-4

3e-4

9e-4

2e-3

7e-3

2e-2

5e-2

Freq, Hz

Fr(Tv)=0.04 * e(-0.09*Tv)



• Hexcel with contact to a surface initiates spikesHexcel with contact to a surface initiates spikes• Hexcel with contact to HRC is “working“ much Hexcel with contact to HRC is “working“ much

“better”“better”• Shapes of signals are similar to ATLAS and Shapes of signals are similar to ATLAS and

PSPICE model which was shown last yearPSPICE model which was shown last year• Removing a water from hexcel by vacuum Removing a water from hexcel by vacuum

without baking :without baking :– decreases the rate of spikes (in 20 times/30h in my decreases the rate of spikes (in 20 times/30h in my

setup), setup), – first view -> it does not change the shapes (?), first view -> it does not change the shapes (?), – Amplitude (? ->low statistic, it seems to be go down ).Amplitude (? ->low statistic, it seems to be go down ).

• How much time is needed to dry ATLAS? How much time is needed to dry ATLAS? ~400000 times more?~400000 times more?

• Next steps ?Next steps ?

Conclusion:Conclusion:



• Where are electrons collecting Where are electrons collecting before a discharging?before a discharging?– At the island in HRC (left)?At the island in HRC (left)?– Inside or on surface of HEXCEL (right)? Inside or on surface of HEXCEL (right)?

Questions for a discussion:Questions for a discussion:

- ---

Spark through a glue

Spark through

a gap

HRC (+HV)

HEXCEL cell wall

(as conductance)HRC (GND)

- -



• In both cases HEXCEL is working as In both cases HEXCEL is working as conductanceconductance

• Conductance depends from Conductance depends from humidityhumidity

• First case is understood, electrons First case is understood, electrons can collect on islandcan collect on island

• Second case Second case ??? On surface, ??? On surface, inside….inside….

Questions for a discussion:Questions for a discussion:



More examples of signal shapesMore examples of signal shapes

(No comments)(No comments)

More slides More slides



Examples of signalsExamples of signals

run203run203

A, mV

# sample

# sample

A, mV




run205run205

# event

A, mV



#

sample

A, mV


run205run205




run208run208

Ev 143 Ev 370

A, mV

#

sample



Answer to Peter concerning Answer to Peter concerning Cu+Hexcel rate Cu+Hexcel rate

• But i am still worried about the extreme low rate of your hexcel+Cu: itBut i am still worried about the extreme low rate of your hexcel+Cu: itlooks like you are here almost down to 0! You never had such a low ratelooks like you are here almost down to 0! You never had such a low ratebefore - as far as i can see. So there has to be a dramatic decline ofbefore - as far as i can see. So there has to be a dramatic decline ofhecspikes when going to very low humidity values. It would be nice to seehecspikes when going to very low humidity values. It would be nice to seethe whole range for this transition ... as you do now with the vacuumthe whole range for this transition ... as you do now with the vacuumchamber!chamber!>>Really I did before only two tests with Cu+Hex: in last March (no signals, but it was very short >>Really I did before only two tests with Cu+Hex: in last March (no signals, but it was very short test,test,

• >>because we were sure, they should not be) and in August (we got a more/less high rate ). >>because we were sure, they should not be) and in August (we got a more/less high rate ). • >>MK and me decided, that it completely depends from humidity. Humidity was very high in >>MK and me decided, that it completely depends from humidity. Humidity was very high in

August.August.• >> Last Cu-test in January, which I show now, happened during the changing of outside >> Last Cu-test in January, which I show now, happened during the changing of outside

temperature,temperature,• >>from plus/zero to strong minus. Humidity goes down, and, I think, I lost signals in 4 days due to >>from plus/zero to strong minus. Humidity goes down, and, I think, I lost signals in 4 days due to • >>humidity.>>humidity.• >>Now I have a hygrometer, and it shows ~8% . Outside temperature = -20C, inside =+25C. >>Now I have a hygrometer, and it shows ~8% . Outside temperature = -20C, inside =+25C. • >>As I want to show in run209, but Run209 is still going to have a statistic, the rate is very low >>As I want to show in run209, but Run209 is still going to have a statistic, the rate is very low • >>now (for now it's 10 events/24h). .>>now (for now it's 10 events/24h). .• • >>About rate goes to 0. Mikhail calculated, that we should wait few years to get on such>>About rate goes to 0. Mikhail calculated, that we should wait few years to get on such• >>small area (5x5cm) a pulse comparison to ATLAS rate....!!!! Maybe we get never 0, if we have>>small area (5x5cm) a pulse comparison to ATLAS rate....!!!! Maybe we get never 0, if we have• >>islands (?).>>islands (?).



Answer to Peter about pressure/load Answer to Peter about pressure/load

on hexcel with PadBoardon hexcel with PadBoard

20 40 60 80 100Event, #

10-003

10-002

10-001

101

102

Freq, Hz

-800 -650 -500 -350 -200 -50

Ampl, mV

0

4

8

12

Run 160

0 30 60 90 120Event, #

-800

-600

-400

-200

0

A, mV

No load

Load

~100g

No load

Load

~100g

No load

Load

~100g

HEC strange signals 1 09 Feb 2012 E.Ladygin Status of HEC spikes study in Protvino E.Ladygin,...

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