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

2. Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -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

3. Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -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

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

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

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

7. Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -7- Laser position scan The higher the pulse width, the more photons enter the diode, meaning the laser is better focused to the hole The dark red color shows the ‘hot spot’, meaning the center of the hole. The red circle shows the assumed ~100um diameter hole. 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.

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

9. Measurements Laser Calibration

10. Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -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 ( 109 Cd and 55 Fe) calibrates the laser beam at different settings

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

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

13. Measurements Laser Bias Scan

14. Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -14- Jitter Jitter vs. input charge (w/ opened detector, no time-walk correction) Jitter vs. laser bias (w/ detector, no time-walk correction) Laser bias (V) 300ps 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)

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

16. Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -16- Pulse Width Pulse width vs. laser bias (w/ opened detector) Pulse width vs. laser bias (w/ detector) 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)

17. Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -17- Pulse Width Pulse width vs. laser bias (w/ opened detector) Pulse width vs. laser bias (w/ 100fF calibration capacitance) 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)

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

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

20. Measurements Detector Bias Scan

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

22. Measurements NINO Threshold Scan

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

24. Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -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 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

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

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

27. Fadmar Osmić – P326 GTK Meeting, December 11, 2007 -27- Pulse Width Comparison 1pF Pulse width vs. laser bias (w/ opened detector) Pulse width vs. laser bias (w/ 1pF calibration capacitance) 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)

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