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UM lab activity. Status report Nov. 9 Work from the last two weeks. Objectives & procedure. Search for traces of discharge spreading between neighboring pixels Check that all the pixels (in our work area) are working – all of the pixels show the same behavior. - PowerPoint PPT Presentation
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Dan Levin, Yiftah Silver 1
UM lab activity
Status report Nov. 9Work from the last two weeks
11/9/2010
Dan Levin, Yiftah Silver 2
Objectives & procedure
• Search for traces of discharge spreading between neighboring pixels1. Check that all the pixels (in our work area) are
working – all of the pixels show the same behavior.
2. Trigger on one pixel and check the signal induced on it’s neighboring pixels
3. Repeat for different configurations of trigger and neighbors.
11/9/2010
Dan Levin, Yiftah Silver 3
Measurement setup• PV1-99%Ar-1%CF4 @700 Torr• Large part of the panel is covered with tape to minimize the
noise induced by light.• Trigger threshold: -1V• Collimator ~20cm lead with square aperture ~4mm^2
RO-26
RO-27
RO-28
RO-29
RO-30
VP1
HV lines– 93-96
20 pixels were tested.
26
27
28
29
30
96
HV
93 94 95
11/9/2010
Dan Levin, Yiftah Silver 4
Electrical Setup
HVRq=10MOhm
Rout=100[Ohm]
20 dB atten
Discriminator @ 100 mV
SnO2
Ni
11/9/2010
Up to 6 different read out channels
Up to 8 separately quenched HV channels
Dan Levin, Yiftah Silver 511/9/2010
23cm
2.8 mCi
Pb filled collimatorthe “zayin”
1/8” x 1/8” square aperture
handle
The panel
Dan Levin, Yiftah Silver 6
Single pixel (26x96) 880V • Amplitude 10-12V• Leading fall time:2-4ns– 10%-90%
• Full recovery time 150-200 ns.
• All pixels show same characteristics.
•
2V
2V
5ns
50ns
Effective capacitance of one pixel:8±2 [pF]
26
27
28
29
30
96
HV
11/9/2010
Dan Levin, Yiftah Silver 7
Signal from 20 (single) pixelsPixel Ni\SnO2 93 [#/min] 94 [#/min] 95 [#/min] 96 [#/min]
26 Bkg -21/5Src – 29/3
Bkg -10/3 Src – 24/3
Bkg -16/3 Src – 33/3
Bkg -16/3 Src – 31/3
27 Bkg – 15/5Src – 45/5
Bkg – 10/3Src – 24/3
Bkg – 11/3Src – 33/3
Bkg – 11/3Src – 20/3
28 Bkg – 11/3Src – 20/3
Bkg – 74/3Src – 163/3
Bkg – 43/3Src – 101/3
Bkg – 12/3Src – 28/3
29 Bkg – 13/3Src – 27/3
Bkg – 8/3Src – 36/3
Bkg – 8/3Src – 25/3
Bkg – 13/3Src – 35/3
30 Bkg – 12/3Src – 30/3
Bkg – 29/3Src – 69/3
Bkg – 24/3Src – 31/3
Bkg – 30/3Src – 50/3
All the measurements above were done at a voltage of 880V
11/9/2010
Dan Levin, Yiftah Silver 8
Search for discharge spreading
• New connectors allow measurement of 6 separate (or ganged) lines.
• Each HV line is terminated separately with a 10MOhm resistor.
• The idea is to trigger on the center pixel and to check the signal induced on the neighboring pixels
11/9/2010
Dan Levin, Yiftah Silver 9
Search for discharge spreading single HV line
• Green – pixel (28x96)• Red- 2 pixels on each side
(26,27,29,30x96 ) all ganged together.
• Same signal shape for the triggered pixel.
• A positive pulse on the neighboring pixels.
• All positive pulses show the same “double peak” behavior.
50ns1V
5V
Bkg- 10/3 [#/min]Src- 21/3 [#/min]
Rate measurements26
27
28
29
30
96
HV
11/9/2010
Dan Levin, Yiftah Silver 10
Search for discharge spreading single HV line
• Green – pixel (28x96)• Red- 1 pixels on each side
(27,29x96 ) ganged together.• Same signal shape for the
triggered pixel.• A positive pulse on the
neighboring pixels.• All positive pulses show the
same “double peak” behavior.
•
5V
1V 50ns
Rate measurements:Bkg - 6/3 [#/min]Src - 22/3 [#/min]
26
27
28
29
30
96
HV
11/9/2010
Dan Levin, Yiftah Silver 11
Search for discharge spreading single HV line
• Green – pixel (28x96)• Red- pixel (27x96)• Same signal shape for the
triggered pixel.• A positive pulse on the
neighboring pixel.• Rate measurement:
• Bkg – 8/3 [#/min]• Src – 17/3[#/min]
•
5V
1V 50ns
26
27
28
29
30
96
HV
11/9/2010
Dan Levin, Yiftah Silver 12
Search for discharge spreading single HV line
• Green – pixel (27x96)• Red- pixel (28x96)• Same signal shape for the
triggered pixel.• Same positive pulse on the
neighboring pixel.• Rate measurement:
• Bkg – 7/3 [#/min]• Src – 22/3 [#/min]
•
5V
1V 50ns
Different pixel – same signal… 26
27
28
29
30
96
HV
11/9/2010
Dan Levin, Yiftah Silver 13
Test for discharge spreading – Two HV lines
• HV lines 95,96 separately quenched with 10MOhm
• Green- RO line 28 (triggered)• Red – RO line 27• Rate measurements:
– Bkg 8/3 [#/min]– Src 40/3 [#/min]
•
5V
1V 50ns
26
27
28
29
30
96
HV
95
11/9/2010
Dan Levin, Yiftah Silver 14
Test for discharge spreading 4 HV lines
• HV lines 93-96 separately quenched with 10MOhm
• Green- RO line 28 (triggered)• Red – RO line 26,27,29,30 all
ganged together.• Rate measurements:
– Bkg: 38/3 [#/min]– Src: 74/3 [#/min]
•
26
27
28
29
30
96
HV
93 94 95
5V
1V50ns
880V gave rise to many “after-pulses”. this measurement was done at 870VMost signals looks like this but not all…11/9/2010
Dan Levin, Yiftah Silver 15
Different signals shapes – 4 HV lines
5V
1V50ns
Possible discharge spreading???
11/9/2010
Dan Levin, Yiftah Silver 16
Conclusions
• Results from measurements of one and two HV line shows no trace of discharge spreading!!! (along the SnO2 electrodes)
• It “looks like” most of the time there is no discharge spreading between pixels on the Ni electrodes.
• We will be able to give a better conclusion when readout is available on the HV lines as well.
11/9/2010