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UM lab activity

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.

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UM lab activity

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  1. UM lab activity Status report Nov. 9 Work from the last two weeks Dan Levin, Yiftah Silver

  2. 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. • Trigger on one pixel and check the signal induced on it’s neighboring pixels • Repeat for different configurations of trigger and neighbors. Dan Levin, Yiftah Silver

  3. Measurement setup HV • 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 93 94 95 96 26 HV lines– 93-96 27 RO-26 28 RO-27 VP1 20 pixels were tested. 29 RO-28 30 RO-29 RO-30 Dan Levin, Yiftah Silver

  4. Electrical Setup Up to 8 separately quenched HV channels Rq=10MOhm HV SnO2 Ni Rout=100[Ohm] 20 dB atten Discriminator @ 100 mV Up to 6 different read out channels Dan Levin, Yiftah Silver

  5. handle 2.8 mCi Pb filled collimator the “zayin” 23cm 1/8” x 1/8” square aperture The panel Dan Levin, Yiftah Silver

  6. Single pixel (26x96) 880V HV • Amplitude 10-12V • Leading fall time:2-4ns • 10%-90% • Full recovery time 150-200 ns. • All pixels show same characteristics. 96 26 50ns 2V 27 28 Effective capacitance of one pixel: 8±2 [pF] 29 2V 30 5ns Dan Levin, Yiftah Silver

  7. Signal from 20 (single) pixels All the measurements above were done at a voltage of 880V 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 Dan Levin, Yiftah Silver

  9. Search for discharge spreading single HV line HV • 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. 5V 96 1V 50ns 26 27 28 29 30 Bkg- 10/3 [#/min] Rate measurements Src- 21/3 [#/min] Dan Levin, Yiftah Silver

  10. Search for discharge spreading single HV line HV • 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. 96 5V 26 1V 50ns 27 28 29 30 • Rate measurements: • Bkg - 6/3 [#/min] • Src - 22/3 [#/min] Dan Levin, Yiftah Silver

  11. Search for discharge spreading • single HV line HV • 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] 96 5V 26 1V 50ns 27 28 29 30 Dan Levin, Yiftah Silver

  12. Search for discharge spreading single HV line HV • 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] 96 5V 26 1V 50ns 27 28 29 30 Different pixel – same signal… Dan Levin, Yiftah Silver

  13. Test for discharge spreading – Two HV lines HV • 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] 95 5V 96 50ns 26 1V 27 28 29 30 Dan Levin, Yiftah Silver

  14. Test for discharge spreading 4 HV lines HV • 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] 5V 93 94 95 96 50ns 1V 26 27 28 880V gave rise to many “after-pulses”. this measurement was done at 870V Most signals looks like this but not all… 29 30 Dan Levin, Yiftah Silver

  15. Different signals shapes – 4 HV lines 5V 50ns 1V Possible discharge spreading??? 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. Dan Levin, Yiftah Silver

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