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

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 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 … Timon Heim 2 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 Timon Heim 3 Instrumentation Meeting

Final Tuning ThresholdDist NoiseDist 800 600 700 500 600 400 Number of Pixels Number of Pixels 500 400 300 300 200 200 100 100 0 0 0 200 400 600 800 1000 0 20 40 60 80 100 Threshold [e] Noise [e] Timon Heim 4 Instrumentation Meeting

Final Tuning II ThresholdDist NoiseDist 800 600 700 500 600 400 Number of Pixels Number of Pixels 500 400 300 300 200 200 100 100 0 0 0 200 400 600 800 1000 0 20 40 60 80 100 Threshold [e] Noise [e] Timon Heim 5 Instrumentation Meeting

USBpix Noise Tuning 600 450 400 500 350 400 300 # of Pixels # of Pixels 250 300 200 200 150 100 100 50 0 0 0 5 10 15 20 25 30 100 200 300 400 500 600 700 800 900 1000 TDAC Setting Threshold [e] Timon Heim 6 Instrumentation Meeting

PreComparator Circuit VthP VthP 4 bit DAC 4 bit DAC in+ in- Bias Transistor (@IpreCmpVbn) Timon Heim 7 Instrumentation Meeting

TDAC Encoding Value Sign TDAC 0 1 15 1 1 14 … … … 15 1 0 16 0 0 … … … 31 0 14 32 0 15 Timon Heim 8 Instrumentation Meeting

Tuning procedure OccupancyDist-0 OccupancyDist-1 OccupancyDist-2 1600 1200 350 1400 300 1000 1200 250 800 Number of Pixels Number of Pixels Number of Pixels 1000 200 800 600 150 600 400 100 400 200 50 200 0 0 0 0 10 20 30 40 50 0 10 20 30 40 50 0 10 20 30 40 50 Occupancy Occupancy Occupancy OccupancyDist-3 OccupancyDist-4 180 250 160 200 140 120 Number of Pixels Number of Pixels 150 100 80 100 60 40 50 20 0 0 0 10 20 30 40 50 0 10 20 30 40 50 Occupancy Occupancy Timon Heim 9 Instrumentation Meeting