FE65-P2 Tuning & More Instrumentation Meeting - 20th May 2016 - - PowerPoint PPT Presentation

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FE65-P2 Tuning & More Instrumentation Meeting - 20th May 2016 Timon Heim - LBNL UNIVERSITY OF 1 CALIFORNIA Crosstalk Crosstalk: Observing second threshold Crosstalk from injection line, directly into preamp input (~1/10th of

SLIDE 1

UNIVERSITY OF CALIFORNIA

Timon Heim - LBNL

FE65-P2 Tuning & More

Instrumentation Meeting - 20th May 2016

SLIDE 2

Timon Heim 2 Instrumentation Meeting

Crosstalk

Crosstalk:

Observing second threshold
Crosstalk from injection line, directly

into preamp input (~1/10th of injection cap)

Confirmed by disabling readout of pixels

which are not being injected into

Missing hits:

Seeing missing hits at high injection
Not visible when running pixel by pixel
Perhaps some kind of common mode

level shift, to be confirmed …

SLIDE 3

Timon Heim 3 Instrumentation Meeting

Tuning

Procedure:

Occupancy based tuning
Inject at target threshold
Adjust threshold so that you see 50% of

the injections

Global threshold found by stepping down

from high Vthin1 DAC setting to avoid running into noise

Pixel threshold found by binary search

algorithm

TDAC distribution:

Saw that TDAC distribution is heavily

lopsided (25% at TDAC = 0)

Also observed high amount of pixels

failing s-curve fit

Caused by leaving

Vthin2 DAC at 0, making 50% of the TDAC range unusable

Setting

Vthin2 DAC to 50/100 helps

To be determined which common mode

(Vthin1Dac - Vthin2Dac) is the best, probably center

SLIDE 4

Timon Heim 4 Instrumentation Meeting

Final Tuning

100 200 300 400 500 600 700 800 200 400 600 800 1000 Number of Pixels Threshold [e] ThresholdDist 100 200 300 400 500 600 20 40 60 80 100 Number of Pixels Noise [e] NoiseDist

SLIDE 5

Timon Heim 5 Instrumentation Meeting

Final Tuning II

100 200 300 400 500 600 20 40 60 80 100 Number of Pixels Noise [e] NoiseDist 100 200 300 400 500 600 700 800 200 400 600 800 1000 Number of Pixels Threshold [e] ThresholdDist

SLIDE 6

Timon Heim 6 Instrumentation Meeting

USBpix Noise Tuning

50 100 150 200 250 300 350 400 450 100 200 300 400 500 600 700 800 900 1000 # of Pixels Threshold [e] 100 200 300 400 500 600 5 10 15 20 25 30 # of Pixels TDAC Setting

SLIDE 7

Timon Heim 7 Instrumentation Meeting

PreComparator Circuit

Bias Transistor (@IpreCmpVbn)

VthP VthP in- in+ 4 bit DAC 4 bit DAC

SLIDE 8

Timon Heim 8 Instrumentation Meeting

TDAC Encoding

Value Sign TDAC 1 15 1 1 14 … … … 15 1 16 … … … 31 14 32 15

SLIDE 9

Timon Heim 9 Instrumentation Meeting

Tuning procedure

200 400 600 800 1000 1200 1400 1600 10 20 30 40 50 Number of Pixels Occupancy OccupancyDist-0 200 400 600 800 1000 1200 10 20 30 40 50 Number of Pixels Occupancy OccupancyDist-1 50 100 150 200 250 300 350 10 20 30 40 50 Number of Pixels Occupancy OccupancyDist-2

20 40 60 80 100 120 140 160 180 10 20 30 40 50 Number of Pixels Occupancy OccupancyDist-3 50 100 150 200 250 10 20 30 40 50 Number of Pixels Occupancy OccupancyDist-4