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Wiener-Crate noise report

Wiener-Crate noise report. F. Gonnella - Laboratori Nazionali di Frascati Photon Veto Workng Group, CERN 0 4 /06/ 2013. Study of noise in Wiener crate. Common mode noise setup. 2 high impedance probes connected with resistor rheophores A 20 Gs /s 1GHz BW oscilloscope AC coupled.

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Wiener-Crate noise report

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  1. Wiener-Crate noise report F. Gonnella- LaboratoriNazionali di Frascati Photon Veto Workng Group, CERN 04/06/2013

  2. Study of noise in Wiener crate Francesco Gonnella - LNF

  3. Common mode noise setup • 2 high impedance probes connected with resistor rheophores • A 20 Gs/s 1GHz BW oscilloscope AC coupled Francesco Gonnella - LNF

  4. Noise with crate unloaded • Crate unloaded • Noise is ~1 V (peak-peak) +7V 1.6 μs -7V Francesco Gonnella - LNF

  5. Noise with loaded crate • Crate loaded with 4 LAV FE boards + 1 Tel Board • Noise is ~0.5 V (peak-peak) +7V -7V Francesco Gonnella - LNF

  6. Noise at 20MHz bandwidth • Crate loaded with 4 LAV FE boards + 1 Tel Board • Noise is ~30 mV (peak-peak) +7V -7V Francesco Gonnella - LNF

  7. Noise vs current (full bandwidth) Francesco Gonnella - LNF

  8. Noise vs current (20 MHz BW) • Negative power supply seems to perform much better than positive one Francesco Gonnella - LNF

  9. Common mode noise filter setup We used the setup recommended by Wiener with a Common Mode Filter and coupled the signal in AC Francesco Gonnella - LNF

  10. Filtered vs. not filtered (full BW) Without coil With coil Francesco Gonnella - LNF

  11. Filtered vs. not filtered (20 MHz) Without coil With coil Francesco Gonnella - LNF

  12. Frequency spectrum: full BW, no CM filter 20 MHz Francesco Gonnella - LNF

  13. Frequency spectrum: full BW, CM filtered 20 MHz Francesco Gonnella - LNF

  14. Frequency spectrum: 20 MHz, no CM filter 20 MHz Francesco Gonnella - LNF

  15. Frequency spectrum: 20 MHz, CM filtered 20 MHz Francesco Gonnella - LNF

  16. Consequences on LAV Front-end electronics Francesco Gonnella - LNF

  17. Noise in LAV FEE test • We performed two different runs for each test • No signal: all final conditions but pulser is Off • Signal: pulser On (100mV signal, ~10mV threshold) • Board is moved outside the crate and powered it with linear PS • Analogue sums are perfectly clean • Test with TDC showed that the situation is noiseless Francesco Gonnella - LNF

  18. Noise in LAV FEE inside crate No signal 100mV signal Rate in Hz extrapolated using the total effective acquired time: Tacq = 3.5E3 * 0.5E-6 * 7 = 1.2E-2s The noise rate goes to ~Hz if the nominal Thr is higher than 7mV (nominal) Francesco Gonnella - LNF

  19. Noise in LAV FEE linear PS (no crate) No signal 100mV signal The board has been moved out from the crate to a table and the ±7.5V power is provided by an external linear power supply. Francesco Gonnella - LNF

  20. Noise rate in LAV FEE in Wiener Rate Hz Threshold mV Francesco Gonnella - LNF

  21. Analogue sum: crate loaded Sum 1-4 Sum 28-32 Francesco Gonnella - LNF

  22. Analogue sum: crate unloaded Sum 1-4 Sum 28-32 Francesco Gonnella - LNF

  23. Time resolution on LAV FEE boards • Time resolution in “good” channels is around 100 ps • In “bad” channels is around 200 ps • “Bad” channels are all in the last part of the board • “Bad” channels are the noisy channels previously shown Francesco Gonnella - LNF

  24. Conclusions (1/2) • Crate specification are 20 mV differential p-p in 0 – 20 MHz bandwidth; • No specification is provided at higher frequency • No specification is provided on common-mode noise! • Without any filter we measured up to 0.5 V noise, peaked at 250MHz • The crate specs are respected if we measure the noise as defined in the specs • With common-mode filter and bandwidth limitation to 20MHz • Specifications on how the measurement should be done filter out completely high frequency and common-mode noise Francesco Gonnella - LNF

  25. Conclusions (2/2) • Common-mode noise is there and has bad consequenceson LAV FEE: • Last 12 channels are noisy up to ~10 mV threshold • Minimum threshold due to crate instead of FEE performance • Further measurements must be done in ECN3 a.s.a.p. • We are planning to perform a cosmic-ray test using A11(rotated for this purpose) with Wiener crate and LAV FEE • Differential FEE should be immune to common-mode noise • e.g. CEDAR did not experience any noise issue • No problem is foreseen for threshold higher than 15 mV • e.g. CHOD and MUV should not experience problem (also using LAV FEE) Francesco Gonnella - LNF

  26. Thank you for you attention francesco.gonnella@lnf.infn.it

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