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NINO RO chip qualification with the laser test system

NINO RO chip qualification with the laser test system. Sakari and Fadmar. Diode specifications - reminder. Pixelized diode from the IRST wafer 200 um thickness 300 um x 300 um pixel dimension (nominal) 3 x 20 pixel matrix 1 pixel under study  neighboring pixels grounded

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NINO RO chip qualification with the laser test system

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  1. NINO RO chip qualification with the laser test system Sakari and Fadmar

  2. Diode specifications - reminder • Pixelized diode from the IRST wafer • 200 um thickness • 300 um x 300 um pixel dimension (nominal) • 3 x 20 pixel matrix • 1 pixel under study  neighboring pixels grounded • An opening in the Al-layer covering the p+-pad etched to allow laser illumination Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -2-

  3. Opening in the Al-layer • From the previous measurements it was seen that there’s a big uncertainty on focusing the laser beam into the diode •  A better mechanical stability was achieved •  An opening in the Al-layer of the diode to provide better photon injection was etched • The opening was made by Serge Ferry (chemical lab) • The hole was done with chemical etching. A photo-resist was placed to protect the rest of the Al-layer. The diameter of the opening is ~100 um • With the opening the laser may be manually scanned to the center providing a maximum photon injection Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -3-

  4. Opening in the Al-layer Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -4-

  5. IRST diode pixelized and wire-bonded Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -5-

  6. Connection to the NINO chip Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -6-

  7. Laser position scan To make sure all the photons are injected in to the diode, the laser beam is manually focused by measuring the output pulse width at different positions. The dark red color shows the ‘hot spot’, meaning the center of the hole. The red circle shows the assumed ~100um diameter hole. The higher the pulse width, the more photons enter the diode, meaning the laser is better focused to the hole Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -7-

  8. Height scan SATURATION Complete illumination with the laser light  calibration possible using an ALICE SPD assembly (same sensor specifications) Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -8-

  9. Measurements Laser Calibration

  10. Calibration of the laser light • Reminder: W/O calibration between the laser and input charge the measurements with a calibration capacitance and the diode are incomparable • BUT!!! Cross calibration possible with an Alice SPD assembly • Assumptions: • The complete laser beam illuminates the detector  demonstrated (plateau reached in the fiber height scan) • Sensors of the ALICE SPD assemblies have the same specifications as the detector under study  they come from Si-wafers with same specifications • Response of the ALICE SPD assembly to two different radioactive sources (109Cd and 55Fe) calibrates the laser beam at different settings Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -10-

  11. Pulse Area vs Laser Bias Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -11-

  12. Laser Calibration Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -12-

  13. Measurements Laser Bias Scan

  14. Jitter 300ps 300ps Laser bias (V) Laser bias (V) 2.6 3.6 4.7 6.3 7.3 8.3 9.2 10 10.7 Generated charge (fC) 2.6 3.6 4.7 6.3 7.3 8.3 9.2 10 10.7 Generated charge (fC) Jitter vs. laser bias (w/ detector, no time-walk correction) Jitter vs. input charge (w/ openeddetector, no time-walk correction) Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -14-

  15. Jitter 300ps 50ps Laser bias (V) 2.6 3.6 4.7 6.3 7.3 8.3 9.2 10 10.7 Generated charge (fC) Jitter vs. laser bias (w/ 100fF calibration capacitance no time-walk correction) Jitter vs. input charge (w/ opened detector, no time-walk correction) Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -15-

  16. Pulse Width Laser bias (V) Laser bias (V) 1.5 2.6 3.6 4.7 6.3 7.3 8.3 9.2 10 10.7 Generated charge (fC) 1.5 2.6 3.6 4.7 6.3 7.3 8.3 9.2 10 10.7 Generated charge (fC) Pulse width vs. laser bias (w/ opened detector) Pulse width vs. laser bias (w/ detector) Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -16-

  17. Pulse Width Laser bias (V) 1.5 2.6 3.6 4.7 6.3 7.3 8.3 9.2 10 10.7 Generated charge (fC) Pulse width vs. laser bias (w/ 100fF calibration capacitance) Pulse width vs. laser bias (w/ opened detector) Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -17-

  18. Time-walk vs. Pulse width Time-walk vs. Pulse width (w/ opened detector) Time-walk vs. Pulse width (w/ detector) Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -18-

  19. Time-walk vs. Pulse width Time-walk vs. Pulse width (w/ opened detector) Time-walk vs. Pulse width (w/ 100fF calibration capacitance) Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -19-

  20. Measurements Detector Bias Scan

  21. Pulse width and Jitter =~3 MIPs =~3 MIPs Pulse width vs. detector bias (w/ opened detector) Jitter vs. detector bias (w/ opened detector) Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -21-

  22. Measurements NINO Threshold Scan

  23. Jitter as function of the NINO threshold for 3 different laser bias settings Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -23-

  24. Conclusions • Mechanical stability achieved • New precision mechanics installed • NINO board fixed to a reference plane • repeatability tested and improved •  system mechanically stable • Opening in the Al-layer allows the complete illumination with the laser light • Procedure established with TS/DEM group • Verified on 5 samples  openings range from 100 um – 3 mm • laser calibration finally! possible • Measurements on the NINO chip show improved results: jitter <200 ps for high det-bias and >1.8 V laser bias (~3 MIPs) • With the current RO-setup (detector wire-bonded to the NINO chip, no pre-amp) NO further improvement possible! • Next step: demonstrator Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -24-

  25. SPARE SLIDES Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -25-

  26. Jitter Comparison 1pF 300ps 300ps Laser bias (V) 2.6 3.6 4.7 6.3 7.3 8.3 9.2 10 10.7 Generated charge (fC) Jitter vs. laser bias (w/ 1pF calibration capacitance no time-walk correction) Jitter vs. input charge (w/ opened detector, no time-walk correction) Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -26-

  27. Pulse Width Comparison 1pF Laser bias (V) 1.5 2.6 3.6 4.7 6.3 7.3 8.3 9.2 10 10.7 Generated charge (fC) Pulse width vs. laser bias (w/ 1pF calibration capacitance) Pulse width vs. laser bias (w/ opened detector) Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -27-

  28. Time-walk vs. Pulse widthComparison 1pF Time-walk vs. Pulse width (w/ opened detector) Time-walk vs. Pulse width (w/ 1pF calibration capacitance) Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -28-

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