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The latest n-XYTER Test Results

The latest n-XYTER Test Results. Krzysztof Kasiński (AGH Kraków). Acknowledgements: Paweł Gryboś, Robert Szczygieł (AGH, Cracow) Adam Czermak, Bogdan Sowicki (INP, Cracow). cincian@o2.pl. CBM Collaboration Meeting 26.02.2008 . Presentation Outline. Hardware & Software

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The latest n-XYTER Test Results

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  1. The latest n-XYTER Test Results Krzysztof Kasiński (AGH Kraków) Acknowledgements: Paweł Gryboś, Robert Szczygieł (AGH, Cracow) Adam Czermak, Bogdan Sowicki (INP, Cracow) cincian@o2.pl CBM Collaboration Meeting 26.02.2008

  2. Presentation Outline • Hardware & Software • Uniformity Measurements • Front-End gains • Thresholds • Comparator Threshold Correction • Timestamp Resolution Analysis • First Acquisitions With Si Detector • Laser diode • Strontium Sr90 • Summary CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  3. Sucima Imager DAQ board + n-Xyter Mainboard Heatsink Absolutely required! > 150 *C ~70 *C 2 n-Xyter ASICs AC coupled detector Virtex 2 FPGA I2C USB 2.0 LVDS Monitor & test pins Detector bias CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  4. ASICs and Detector Silicon detector 128-stripes AC-coupling 75 um pitch 1 cm length Heatsinks Required! >90 *C ~50 *C Several channels left floating top bottom CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  5. The Software layer CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  6. Uniformity test - thresholds connected to detector floating inputs Threshold [reg.value] CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  7. Uniformity test - thresholds Threshold [reg.value] Threshold [reg.value] Threshold [reg.value] Threshold [reg.value] CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  8. TrimDAC test Step: 0.69 LSB Coverage: 19.42 LSB threshold correction CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  9. After the threshold correction... Threshold [reg.value] CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  10. After the threshold correction 2.1771 0.432 2.6861 0.352 Threshold [reg.value] Threshold [reg.value] 2.0909 0.412 2.2021 0.499 Threshold [reg.value] Threshold [reg.value] CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  11. Timestamp resolution – sources of errors Ideal case: Duty cycle different than 50%: Non-equal delays: Solution: programmable delay buffers: CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  12. T1 analysis The best configuration 10% of events will have an error on T1 bit disproportion due to the duty cycle =51.17% 1 Region 1 Region 2 Region 3 Region 4 CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  13. T0 analysis optimal configuration disproportion due to the duty cycle =49.3% 7% of events will have an error in T0 bit Region 1 Region 4 Region 2 Region 3 CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  14. Laboratory set-up detector bias Detector daylight coverage & Laser Diode emmiter (replacable by the radiation source) Sucima Imager impulse generator n-XYTER mainboard CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  15. Preliminary results with a detector - Background radiation / noise - Noise cut-off at ~16 [reg.val] Threshold [reg.value] CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  16. Preliminary results with a detector • Pulsed laser diode directed at detector • configurable impulse length (from 20ns) • configurable number of impulses per second • possible manual triggering • (sending certain number of impulses) Only a functional test of a detector + n-XYTER Threshold [reg.value] CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  17. Strontium Sr90 first acquisition • 37 hours of acquisition • ~37000 events-per-channel (total) • detector polarized by 135V • still too small statistic Threshold [reg.value] CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  18. Sr90 threshold scan results Non-conclusive! (due to varying source strenght and threshold spread) Threshold [reg.value] *For figure clarity three most deviated channels were removed CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  19. Sr90 acquisition – spacial radiation strength More counts due to the larger active area created by adjacent not connected stripes general source radiation characteristic not connected not connected masked corrupted channel CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  20. Sr90 treshold scan results After correcting for the source spacial radiation characteristic the channels can be compared *For figure clarity three most deviated channels were removed CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  21. Sr90 threshold scan results averaged counts for all channels (without most deviated ones) Threshold [reg.value] Derivative obtained using central difference formula ? Threshold [reg.value] CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  22. Summary • Optimal register values are still unknown • Comparator Threshold correction works fine • Timestamp resolution: • Bit 0: correction range wide enough, 7% error rate • Bit 1: not possible to fully compensate, 10% error rate • Measurements with detector: • Laser Diode Exciter proved that the full set-up operates properly • Strontium Sr90 – only preliminary measurement • Not enough statistic • Due to the spectrum spread it is not possible to calibrate the system • To Be Done in a near future: • Calibration using other radiation sources (with discrete energy spectrum)s CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  23. Treshold correction summary • Standard deviation before and after correction: A: 2.1771 0.432 C: 2.0909 0.412 B: 2.6861 0.352 D: 2.2021 0.499 • Expected values before and after correction: A: 85.32 96.99 C: 84.46 96.42 B: 85.72 96.35 D: 85.66 96.51 • Expected values spread improvement: 1.26 -> 0.64 (p-p) • TrimDAC current range is vast enough to successfully correct all channels (range: 19.42, step: 0.69 treshold bins) • The resolution of correction can bring down the standard deviation of the tresholds below one treshold bin CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  24. Threshold DAC characteristic CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  25. Sr90 threshold scan results Too small statistic! not-conclusive (nevertheless, a hump is visible) Threshold [reg.value] CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  26. AFE gain PRELIMINARY MEASUREMENTS still optimal values are unknown Settings [reg values]: Icg=255 Vbfb=47 Icg_foll=255 VbiasF=0 iComp=62 iTwc=75 iInv=37 Positive pulse CBM Collaboration Meeting 26.02.2008 Krzysztof Kasiński (AGH Cracow) cincian@o2.pl

  27. Settings [reg values]: Icg=137 Vbfb=0 Icg_foll=49 VbiasF=77 iComp=62 iTwc=75 iInv=37 Positive pulse

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