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Near Detector Electronics Performance

Near Detector Electronics Performance. P. Shanahan 3/18/05 MINOS Collaboration Meeting. Overview. Problems solved FEE Linearity/Calibration SGATEs Pedestal noise MENU failures. Problems Solved. SGATE running 200mF of capacitance on each MASTER crate eliminated problem

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Near Detector Electronics Performance

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  1. Near Detector Electronics Performance P. Shanahan 3/18/05 MINOS Collaboration Meeting Peter Shanahan - Fermilab

  2. Overview • Problems solved • FEE Linearity/Calibration • SGATEs • Pedestal noise • MENU failures Peter Shanahan - Fermilab

  3. Problems Solved • SGATE running • 200mF of capacitance on each MASTER crate eliminated problem • “Channel 4 problem” • Extra data words on MASTER input channel 4 • Affected ~30% of all MASTERs at ~10-5 to 10-6 level • Capacitance on FPGA clock line • Down to 2 problem MASTERs Peter Shanahan - Fermilab

  4. Calibration • As of 3/16/05 18:00 • % deviation from linearity in Charge Injection • 1 entry/channel/ DAC setting • 2 bad channels excluded out of 9240 • Less than 10 other problems not shown due to y-axis limits Peter Shanahan - Fermilab

  5. Calibration Issues • 6 channels have missing fits for 1 range, 1 capid • At least 1 is due to missing bits in FADC – hardware failure we weren’t catching • 2 are on range 7 – hard to populate with DCI points – not relevant • Others not fully understood, but expect new calibration code from Dave R. will eliminate the symptom • 1-2 other 10% level problems • ~ten 2-3% level problems Peter Shanahan - Fermilab

  6. SGATE Running Time Structure: sum(ADC) vs time in SGATE 6 batches Peter Shanahan - Fermilab

  7. SGATE Rates • Beam off run 6818 • Channel Map of number of digits/150 spills • “Dark rate” • ~16Hz/strip, or ~2e-4/strip/spill • Some channels have much more: worst channel = 5 digits/spill Peter Shanahan - Fermilab

  8. Beam off: Noise Hits • Many single digits that appear to be noise just above threshold. • These don’t seem to be calibration problems • Evidence for local coherent noise in ~4 MINDERs • Solutions include • Hardware investigations • Offline strip cut • See Niki’s talk Threshold of 20 counts Line represents typical beam-on contribution in Jan-Feb data Peter Shanahan - Fermilab

  9. Hardware Problems • “Failing MENUs” • “We’re losing ~5/month”: P. Shanahan, Jan. meeting • That was more like 15/month in January and February • Most common symptom is “CapID” error – many possible underlying causes • ~3/4 of these have blown +12V fuse, but are otherwise good • Had been observed on bench during checkout in ~20 channels • not yet understood, but may be “latch up” in QIE? • Most others also fixable – not trace failure due to poor cleaning during assembly. • Recent 12-day period with no failures – Poisson cruelty? Peter Shanahan - Fermilab

  10. Conclusions • NearDet electronics performance very good • SGATE transient solved, “channel-4” problem reduced 2 orders of magnitude. • Drilling down to more rare and more subtle problems • “Peeling an onion” • Noise in SGATE readout mode • Current problems for reconstruction – shouldn’t be hard to handle • Need to investigate cause, as well as possibility of local coherent noise • MENU health: • We’ve had 3-4 failures a week, most of which only require new fuse • Fuse failure is currently a mystery Peter Shanahan - Fermilab

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