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LAV front-end threshold study

LAV front-end threshold study. Mauro Raggi Francesco Gonnella 5 th February 2013 Photon Veto Working Group Meeting. Outline. Noise studies Inside Wiener crate Outside wiener crate Threshold offset studies Using different gain G=5. Threshold offset fine tuning technique Noise at G=5

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LAV front-end threshold study

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  1. LAV front-end threshold study Mauro RaggiFrancesco Gonnella 5thFebruary 2013 Photon Veto Working Group Meeting

  2. Outline • Noise studies • Inside Wiener crate • Outside wiener crate • Threshold offset studies • Using different gain G=5. • Threshold offset fine tuning technique • Noise at G=5 • MIP efficiency studies Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  3. Noise tests @ LNF • We get two different runs for each test • No signal: all final conditions but pulser is Off • Signal: 100mV signal and pulser On • We performed a lot of test: • In Cratethr0 mV nominal • In Crate thr2 mV nominal • In Cratethr5 mV nominal • In Cratethr 7 mV nominal • Board moved outside the crate powering it with linear PS • We immediately concluded that the situation is improving • We did test in the Owen with power from outside Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  4. Noise in WIENER crate 2mV thr 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) Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  5. Noise linear PS 2mV thr 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. Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  6. Block time resolution examples Outside crate G=5 Insidecrate G=3 The uniformity of the time resolution is excellent in the outside crate situation while shows problems due to noise inside the crate. Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  7. The noise itself! • On top: noise shape taken from sums outputs • Bottom: output of FEE digital signal after LVDS to NIM converter • Noise frequency 594KHz which seems to match the operating frequency of different low voltage switching regulators • The noise is coming from the wiener power supply. • Suspect improper grounding in the LNF lab. Test at CERN is foreseen

  8. Thr offset and amplification • We changed the the board 26 amplification setting up 16 new mezzanines modified to get gain=5. • The thr offset have been measured using both G=3 and G=5 with the same procedure in the Front End Test stand • The values of mean offsets scale in reasonable way: Model needed to compensate for amplification • Threshold linearity scan performed G=5 G=3 Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  9. Equalization quality tests • Using just the measured values of the offset with LavFeeTest • We equalized at 10 mV DAQ(Thr (95%))= required value – Offset • Measured the new thr offset with the usual method The quality of the equalization is very good s = 0.15 mV The absolute value has to be corrected for amplification (G=5) 1.43 factor which leads to ~13. mV at the comparator level Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  10. Noise conditions G=5 2mV out Some extra hits observed in presence of the signal with G=5; No extra activity with pulser Off Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  11. Thresholdlinearity test G=3 • All the thr are linear over the exploredrange • Lines have almost the same slope: (1.16 ± 0.02)(mV pulser)/(mV DAQ) Pulse height [mV] @ 95% Programmed DAQ value [mV] Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  12. Thresholdlinearity test G=5 • Lines have almost the same slope: (0.70 ± 0.01)(mV pulser)/(mV DAQ) Pulse height [mV] @ 95% Programmed DAQ value [mV] Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  13. The MIP efficiency measurement • We mounted the LAV FEE026 on the oven and get an acquisition with the following scheme: • We set the thresholds to equalized values using DB Offset values • Using the channel with the single column signal (12-15) we got the efficiency of the 12 equalized blocks at different thresholds • More stringent trigger is also used for the analysis Trigger 15 12 13 14 9 6 0 3 10 4 7 1 11 5 2 8 Trigger 15 12 13 14 Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  14. Triggers performance • Only trigger column coincidence signal • Added the request for at least 1 other block in the column Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  15. MIP efficiency oven triggers The average MIP efficiency is quite different: Is that due to different muon sample or to noisy oven triggers? 1 more block Oven Trg Spurious effect due to trigger request and inefficiency in last channel Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  16. Block time resolution Strange peaks in the distribution. Resolution order 2ns with no slewing correction and unknown trigger time resolution included! s ~ 0.5ns/√E Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  17. Leading and leading-trailing Eff Leading and trailing Leading only 10mV 5mV The leading and trailing difference seems not so big as we could expect! Investigating… Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  18. Threshold scan results:1 more block in the trigger Thr = 5mV Thr = 7.5mV Thr = 10mV Both boards thr and oven equalization look reasonably good for low thrsSecond order fine tuning can be obtained using HV or thr adjustments Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  19. The ToT puzzle Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  20. Conclusions • Status: • We discovered the origin of noise (Wiener PS) • The quality of equalization procedure seems good • We obtained a first estimate of muon efficiency tobe ~90% at 5mV thr with G=5 in the board. • First look at time resolution seems Ok. • Things to do: • Check the effect of oven extra cables on signal shape and efficiency • Finish trigger optimization (time cuts) • Try to further increase the amplification G=6 G=9? • Fix an amplification value on the basis of g data spectrum (data and MC) Mauro Raggi - I.N.F.N. - Laboratori Nazionali di Frascati - Italy

  21. Thank you for your attention

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