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Timing, Gain Calibration, Error Banks

Timing, Gain Calibration, Error Banks. K. Akiba. Commissioning. The software developments/issues reported here are dedicated towards the commissioning of the Velo. Timing affects directly the quality of the data: precision is required.

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Timing, Gain Calibration, Error Banks

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  1. Timing, Gain Calibration, Error Banks K. Akiba Kazu Akiba

  2. Commissioning • The software developments/issues reported here are dedicated towards the commissioning of the Velo. • Timing affects directly the quality of the data: precision is required. • The calibration of the gain and eventual equalization of the system were never tried. • It is also the first attempt to understand the sources of DAQ (Tell1) errors and develop methods to correct it. • The tasks involve the combination of PVSS – Vetra – Macros, and eventually an optimisation procedure is developed. Kazu Akiba

  3. Timing Sadia Khalil*, Ivan Mous★ *Syracuse, ★Nikhef Kazu Akiba

  4. ADC digitisation sampling • TELL1 setting, per link granularity == 5.4 k Parameters • Defines the time to digitise the beetle outputs. • Independent of the beam: adjusted with test pulses. • Method to optimise implemented, and checked. Kazu Akiba

  5. Digitisation sampling scan: • Takes the Beetle analogue signals links • 64 links/Tell1, 84 Tell1s. • ADC digitisation scan (DELAYSCAN) runs on the Tell1 with steps of 25/16 ns – Corresponding Vetra job makes the histograms. • Macro analyses the resulting histograms per link basis and sets the optimal delay settings. Kazu Akiba

  6. Digitisation sampling phase: • An xml file is produced and uploaded to the Tell1 recipes. • A set of macros is used to cross-check the optimized values with the expected noise/TP height. TP Value on the optimal delay compared to TP run. Kazu Akiba

  7. Pulse Shape Sampling • To be adjusted to the beam: affects the S/N, spillover and pre-spill. • Velo wrt LHC clock, LHCb trigger • Each sensor wrt to the Velo: time of flight, cable lengths. • Method of time alignment relies on the synchronous modifications of the TTC to each sensor-Tell1. • Mechanism for the determination under development. • Tests using test pulses as “fake beam”: • PVSS scan implemented. • Vetra Analysis in place: pulse shape plot, pulse shape fit. • Under current development: • Cross check and tests with previous TED data. • Implementation of the optimised settings on the PVSS recipes. Kazu Akiba

  8. Pulse shape: the plan • Use Test pulses to measure the pulse shape. • Determine peak time for each sensor: • Minimal data sample approach: event by event fitting with coarse (25 ns) samples. • NZS data analysis. • Fitting with an analytical function as well as a template histogram are under studies. Kazu Akiba

  9. Proof of principle. Peak (ns) Amplitude Credits to Ivan Mous Width 2 Width 1 Constant (offset) Spillover (ns) Kazu Akiba

  10. Checking the Method • Based on sets of 100 events spaced by 25 ns. • Using the Function approach, the Optimum time can be reconstructed for any phase (time shift). • Systematic error in determining the peak time under investigation Kazu Akiba

  11. Applying to the TED run:PRELIMINARY TELL1 29 TELL1 30 Kazu Akiba

  12. Gain Grant McGregor Manchester Kazu Akiba

  13. Measure  Calibrate • First attempt to measure the Gain of different Links. • Current method uses the ADC of the headers (NZS data) as an estimate of gain. • Crosscheck to be done with TP data: needs (both) Timing to be adjusted first. Should be available in the next weeks. Kazu Akiba

  14. First Results: FHS • Separate measurement of the header high value and header low, using last 2 beetle bits: HH-HL = FHS, a pedestal independent quantity. Full Header Swing (FHS) “Header-High” distribution “Header-Low” distribution Kazu Akiba

  15. Variation across links/sensors Low gain/dead links Kazu Akiba

  16. Towards Calibration • Currently the study was performed only with the header ADCs. • Next natural comparison would be with the TP Data. • PVSS scan over the Tell1 gain (Arx DAC) was recently created: to be tested and tuned. • Gain vs step will give the setting to be used. Kazu Akiba

  17. Error Banks Ann Van Lysebetten ★, Chiara Farinelli ★, Tomasz Szumlak* ★ Nikhef, *Glasgow Kazu Akiba

  18. Chasing the TELL1 Errors • Decoder: working, to be debugged further • Pseudo header error: • thresholds determined from Grant’s analysis • PCN errors under investigation: behaviour of the FEM beetle compared to the module. Kazu Akiba

  19. Pseudo Header Errors Def: Failure to determine the header state… Thresholds as they were: almost 0 Pseudo headers. Thresholds 450/550 We can induce errors  So can get rid of them as well

  20. Ultimate Erroneous Goals • Understanding errors: sources and how to fix them based on the error banks solely. • Tuning up the Velo – Eventually export the settings necessary for no Errors. • Error monitoring package: plots and debugging tools. Kazu Akiba

  21. Summaries • Timing: • Digitisation timing under control. • Pulse shape under tests: Uploading procedure being developed, parameters for the TED to be calculated. • Gain: • First measurements show a spread of ~20% • Scan procedure and analysis under development • Error Banks: • Progress towards understanding and adjusting the TELL1. • Set of useful plots to be determined. Kazu Akiba

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