1. News on microstrip detector R&D —Quality assurance tests— Anton Lymanets, Johann Heuser 12 th CBM collaboration meeting Dubna, October 13-18

2. Double sided silicon microstrip detectors 4" wafer, 285 µm n-type Si double metal layer “Baby” sensors Double-sided, 1024 strips per side, 50 µm pitch, 15º stereo angle, full-area sensitive, size: 56  56 mm 2 Double-sided, 256  256 strips, orthogonal, 50(80) µm pitch, size: 15.6  15.6 mm 2 Main sensor CBM01 CBM01 B1 CBM01 B2

3. Measurement procedure Test individual strips: apply 1V, measure the current, obtain resistance Test few groups of strips (~50) per each side Bond detectors to a test board Measure current-voltage behavior

4. Some of the CBM01B2 baby detectors were tested for insulation quality between strip implant and AC contact pads. Procedure: applied 1 V with contact needles, measured the current  resistance derived Test of AC strip insulation quality Probe station at DiamondLab, GSI DC-pad, bias pad AC-pad, bias pad neighboring AC pads AC-DC Test series

5. Detector type: CBM01B2 Wafer: 270529-19 AC-DC insulation n-side p-side AC-bias ring insulation R (Ω) strip # second part of production  bad 

6. p-side AC-bias ring insulation n-side AC-bias ring insulation R (Ω) strip # second part of production  bad  Detector type: CBM01B2 Wafer: 270529-12

7. n-side AC-bias ring insulation n-side p-side AC-bias ring insulation R (Ω) strip # second part of production  (rather) bad  Detector type: CBM01B2 Wafer: 270529-10

8. Detector type: CBM01B2 Wafer: 270529-4 AC-bias ring insulation n-side p-side AC-bias ring insulation strip # R (Ω) first part of production  good  Warm thanks to summer student Andrzej Wilczek for help

9. GSI detector test board Measure overall detector characteristics (i.e. IV-curves) Read-out 32 strips at each side Compatible with connection to n-XYTER kit 10 cm Wire bonded by Harald Deppe (GSI, Darmstadt)

10. Operation Bulk detector current at reverse bias, in a dark box very light sensitive behaviour as expected, OK Observed source-induced pulses on individual strips (oscilloscope) CBM01B2 sensor, wafer 270529-7

11. Another detector CBM01B2 sensor, wafer 270529-10

12. Full detectors 7 pixel detectors; 18 strip detectors. Process status 9/9/2008: total 18 wafers, 12 fully processed, 8 diced CIS-GSI "technology wafer" CBM02 L. Long and R. Rolf, CIS Test wafer to explore primarily radiation tolerance Bias method: punch-through, poly-silicon Breakdown voltage: charge, micro discharge Insulation technology: p-spray, p-stop, field plate Different doping concentration Test structures: 3 Pad diodes, 4 Gate diodes, etc

13. At GSI: 5  8 baby detectors a la type "B2" 2 tested so far on AC insulator quality: OK more to be tested CIS-GSI "technology wafer" CBM02

14. Operation in the beam Mechanics designed and prepared by Wolfgang Niebur et al., GSI Al box, 40 cm  40 cm  20 cm. Covers removed. Legs ~ 50 cm high lift the box from a table to the beam line. Holders of two microstrip detector test boards (10 cm  10 cm) and two front-end boards (one mounted board shown). Please, see talk of Johann Heuser for further details

15. Conclusions First batch of the detectors has been produced in two groups of different quality Available detectors have been tested for AC strip insulation quality and current- voltage behavior Detectors selected for the beam test First look at detectors from new batch: OK Next step – systematic studies of new detectors

16. Backup slide wafer 3 (B2) wafer 3(B4) wafer 9(B4)