Summary of LU tests at 88” cyclotron 19-20 Oct 2014

1. Summary of LU tests at 88” cyclotron 19-20 Oct 2014 IPHC-LBL phone meeting 2014-12-04 Giacomo Contin, Leo Greiner, Jo Schambach, Michal Szelezniak

2. Test conditions • 28 hrs scheduled with heavy ions • October 19, 8:00 – October 20, 12:00 • Total exposure time ~10 hrs + ~40 min for IPHC • Ne LET = 3.49 , Ar LET = 9.74 MeV/(mg/cm2) • 8 hrs scheduled with protons • 6 hrs of beam time  2 hrs of exposure • 50 MeV protons IPHC-LBL phone meeting - 2014_12_04 MS

3. Overview of heavy ion latch-up Data corrected for stuck latch-up reset and reset associated dead time IPHC-LBL phone meeting - 2014_12_04 MS

4. Latch-up count per run • Thousands of LU events at over-current thresholds < 1A • Thin sensors are damaged at thresholds >1 A above the operating current IPHC-LBL phone meeting - 2014_12_04 MS

5. Hiccups in LU recovery Sensor 1 (50m high-res epi) Th = 1.5 A Stuck LU reset Occasionally, after LU recovery, 550 mA (vs 220 mA) (220 mA is for VDD chip + PCB buffers) Sensor 2 (50m high-res epi) Th = 1.0 A Sensor 2 (50m high-res epi) unrecoverable IPHC-LBL phone meeting - 2014_12_04 MS

6. Hiccups in LU recovery Sensor 3 (70m low-res epi) High current after some LU recoveries Th = 1.6 A Th = 2.0 A Sensor 4 (70m high-res epi) Th = 1.4 A IPHC-LBL phone meeting - 2014_12_04 MS

7. Study of current-limited latch-up • Analysis procedure (plots 1-4) • Raw data • Raw data with rising and falling slopes removed • Rising slope: (AvgN:N+20- IN >10 mA) and (IN+20-AvgN:N+20 > 10 mA) • Falling slope: (AvgN:N+20- IN+20 >10 mA) and (IN-AvgN:N+20 > 10 mA) • Histogram of the remaining plateaus • Plateau: average of current samples between slopes • Histogram of the differences between consecutive plateaus ( P(n) – P(n-1)) IPHC-LBL phone meeting - 2014_12_04 MS

8. Current-limited LU, sensor 1, threshold @ 400 mA Current increase by ~300 mA IPHC-LBL phone meeting - 2014_12_04 MS

9. Current-limited LU, sensor 1, threshold @ 800 mA Current increase by ~300 mA and by ~500 mA IPHC-LBL phone meeting - 2014_12_04 MS

10. Current-limited latch-up Sensor 1 For individual runs there appears to be a preference for current-limited latch-up states at +300 mA and + 500 mA Sensor 2 Histograms of current increases in all runs for each sensor are more complex Sensor 3 A more refined analysis may be needed Sensor 4 IPHC-LBL phone meeting - 2014_12_04 MS

11. Protons Ladder 900 mA until it breaks in run 16 Sensor current increases from 220 to 800 mA in run 14 IPHC-LBL phone meeting - 2014_12_04 MS

12. Baseline current consumption ladder sensor Beam on Beam on IPHC-LBL phone meeting - 2014_12_04 MS

13. Proton run data examples Ladder, threshold 760 mA Ladder, threshold 2 A Unrecoverable latch Stuck latch Sensor, threshold 560 mA Sensor, threshold 1400 mA Ladder reset Did not recover Incomplete recovery? IPHC-LBL phone meeting - 2014_12_04 MS

14. Summary * Still activated and not released from the BASE facility IPHC-LBL phone meeting - 2014_12_04 MS

15. Observations • Thousands of non-destructive LU events at overcurrent thresholds < 1A • Hiccups in LU recovery (stuck latch, high power states) => power reset too short? • There appears to be a higher cross-section for current-limited latch-up states at +300 mA and + 500 mA • Heavy ion induced LU damaged thin sensors (threshold ~1A) but not the thick ones • Protons damaged a thick sensor at threshold > 1.4 A (but low statistics) • Threshold current needed for LU-induced damage (?) • PXL ladders in STAR damaged at 800 mA + ~400 mA => total current ~1.2 A • Thin sensors in LU tests damaged at 220 mA + ~1000 mA => total current ~1.2 A IPHC-LBL phone meeting - 2014_12_04 MS

16. IPHC-LBL phone meeting - 2014_12_04 MS

17. IPHC test structures • Testing time: 2 hrs • Total exposure time: 40 min • Ag LET = 48.15 MeV/(mg/cm2) • Woj’s test structure (TOWER): • Exposure of 2 sensors (thick and thin) at the same time • Test setup limitation: LU in one sensor triggers power and SYNC reset, LU in the second sensor triggers only power reset IPHC-LBL phone meeting - 2014_12_04 MS

18. Very preliminary results VDD: ~1.7 V ~1.3 V ~2.2 V IPHC-LBL phone meeting - 2014_12_04 MS

19. Current monitoring (consistent with chip 1) IPHC-LBL phone meeting - 2014_12_04 MS

20. Current measurements High current states? Too many latch-ups? IPHC-LBL phone meeting - 2014_12_04 MS

21. Summary • Current measurements are consistent with LU count in chip 1 • Not finished: • LU count and dead-time corrections (very important for structures that did not register any latch-up) • Extracting from the accumulated data current measurements for chip 2 • LU cross-section for the standard P-well/N-well spacing (0.86 m) and no deep P-well @ 48 MeV/(mg/cm2) ~610-6 cm2 • Phase-1 @ ~37 MeV /(mg/cm2) 110-3 cm2 • Mimosa26 @ ~25 MeV /(mg/cm2) 210-3 cm2 • Ultimate-1 @ 10 MeV /(mg/cm2) 210-5 cm2 • It appears that structures without the deep P-well are more sensitive to latch-up • Should we plan LU tests for other sensors fabricated by TOWER? IPHC-LBL phone meeting - 2014_12_04 MS