Status of measurements of FE-I4 SEU and PRD

1. Status of measurements of FE-I4 SEU and PRD P.Breugnon, M.Menouni, R.Fei, F.Gensolen, A.Rozanov, 06.06.2011

2. GR errors at start of run and Malte’sOn-Off trick • At the beginning very often we got GR readout errors with all bits zero at the start of the run. Many iterations and many warm startups does not help to suppress these GR errors. Probably the problem is amplified by the use of 3.5 m grey flat cable, as other users do not see it with usual short flat cables or ethernet cables. • Usually Malte’s OFF/ON cycling trick solve the problem • After discussion with Malte more understanding of the trick: standard initial configuration switch to active state all or half of the pixels. Noisy pixels could probably perturb GR readout . ON/OFF cycling switch off pixel matrix with default zero parameters and GR configuration in the Start run primitive restore only GR values. So we decided to switch to configuration with PR zero values for GR tests. • Suppressing configure GR option in GRTEST reduce probability of GR read-back errors. Too small delay ? • Other mesures: reducing chip consumption (zero PrmAmp*, DisVbn*), cold start at the beginning of each each run (insure good Vdda from voltage regulators), module configuration only outside beam spill. • With all these measures together we do not observe anymore GR errors at the start of the run

3. Radiation monitoring and GR • Previously reported zero GR error rate was due to the wrong option in the GR readout primitive: configuration was done just before the read-back. Now corrected to read-only. • In the special runs with PS beam pointing GR we observe high rates of GR errors • When beam is pointing to GR position, observe counting latch SEU errors in counter SR24 independent of GR errors. Observed 16 non-zero counts in 237 spills (6.8%) with mean of 2.1 seu/spill. So in average 0.15 seu/spill. • Classification into 6 categories for typical spill of 25 1010 protons/cm2/spill

4. Classification ofGR • 1)Efuseerrors: SEU hard triple memory not involved. • 2)PRDlike resets: All GR bits zero, ServiceRecord almost always zero (SR*=0). Maurice pointed that by changing the order of readout one can correct SR reading. • 3) LVDS errors: One bit LVDS* flips in GR, all SR*=0 • 4)Write glitch from Decoder: One bit flip in GR, SR24=0, SR25>0 • 5)Internal glitch in Global Memory: One bit flip in GR, SR24=0,SR25=0 • 6)Normal GR SEU: one bit in GR is flipped, SR24>0, SR25=0

5. Efuse GR errors • SEU hard triple memory not involved. • Typical rate with GR configure in every spill is 0.7 % (3/429 spills) • For the run with GR configure only at the run start high rate of coherent SEU in 6 bits • Efusedc32 “0->1” • EfusedC35 “0->1” • EfuseRef “15->0” • Typical rate of coherent SEU 3% per spill (5/155 spills) • Maurice propose to study it with/withou correction

6. PRD-like GR errors • Biggest effect in GR errors, SEU hard triple memory not responsible • Typical rate with GR configure in every spill is 5.4 % (23/429 spills) • This rate looks too high for quoted threshold of 100 Mrad/sec during 20 ns. • Our beam intensity corresponds to 0.0065 Mrad/spill or 0.015 Mrad/sec during the spill only • Calibration of PRD wrong ? • Reset glitches ?

7. LVDS GR errors • One LVDS flips in GR • All SR*=0 due to impossible readout • Exact classification not possible due to absense of SR information • Change of readout order proposed by Maurice (GR read+GRconfig+SRread)will allow SR readout in future runs • But anyhow rate is small 0.2% (1/429 spills)

8. Write glitch from Decoder to GR errors • One bit flips in GR • SR24=0 - no SEU in ConfigMemory • SE25>0 - error in Write from Decoder • Typical rate 1.2% (5/429 spills) • Unfortunately single rate of SR25 with beam pointing to GR is very high ~85% • In normal beam position SR25=0 • Could it be reduced ?

9. Internal Global Memory glitch • One bit flips in GR • SR24=0 - no single SEU in ConfigMemory • SE25=0 - no errors in Write from Decoder • Typical rate 0.5% (2/429 spills) • On top of Triple Memory Cells there are some SEU nonhard logic. Is it responsible for these glitches ?

10. Global Memory SEU error • One bit flips in GR • SR24=1 - single SEU in one of 3 redundant bits of Triple ConfigMemory • SE25=0 - no errors in Write from Decoder • Observed rate < 0.2% (0/429 spills) • Normal, as the experimental rate of single SEU SR#24 is 6.8%, so in absense of correlations predicted rate is ~0.003 %

11. Summary GR error rates • Efuse0.7 % (3/429 spills) • PRD-like GR errors 5.4 % (23/429 spills) • LVDS errors 0.2% (1/429 spills) • Write from Decofer 1.2% (5/429 spills) • Internal GlobalMem glitch 0.5% (2/429 spills) • GlobMem SEU< 0.2% (0/429 spills)

12. Preliminary SEU results chips# 27 and 28 • Runs 50,51,52,53,54,76 • Type A (old) DC29 TDAC[1] and FDAC[1] • Type B (new) DC30 TDAC[1] and FDAC[1] • Normal SEU (<40 errors/bunch) • Coherent SEU(>40 errors/bunch ) • Check DC28/DC31 request by Abder

13. Normal SEU chip #27, run 52,DC29- 0ld DC30 -newVdda=1.5V-0.1V

14. Normal SEU chip #27, run 52,DC28- 0ld DC31 -newVdda=1.5V-0.1V

15. SEU asymmetry • run 54, chip 27, Vdda=1.4 V, Clk=1 Mhz • Old 0->1 623 bits flipped • Old 1->0 214 bits • New 0->1 4 bits • New 1->0 14 bits • Old R01= 2.9 • New R01= 0.29 • So biggest gain is in 0->1 transitions

16. Very preliminary SEU results chips# 27,28 • Normal SEU per spill ~20 10 10 protons/cm2 • Vdda1= 1.5V – 0.1V(drop) • Chip 27 Type A 2.8 seu/spill/672bits (last week 4.6) • Chip 27 Type B 0.1 seu/spill/672bits • Chip 28 Type A 3.0 seu/spill/672bits (last week 8.0) • Chip 28 Type B 0.1 seu/spill/672bits

17. Conclusions • Abnormal high PRD rates: calibration of PRD or reset glitches ? • Too high Write decoder rates. • Too high Internal Global Memory glitches • Normal Triple Global Memory SEU are low • New/old pixel SEU latches verified in DC28/DC31: much better performance of new latches • 0->1 versus 1->0 SEU asymmetry opposite in new PR latches • More runs (3x12 hours) at PRD/GR position agreed forthis week

18. Spare

19. Measurements • Two FE-I4 chips installed in the PS beam Irrad3 • Chip ID28 (PC marslhc) • Chip ID27 (PC marnach) • Also chip SEU3D installed • Order in the beam ID27,ID28,SEU3D • Al foils on ID27 and SEU3 • Orientation: EOC on the top, beam traverse first PCB, second the chips • Horizontal beam position in the center (columns 39/40) • Vertical beam position 5mm down from the center (far from EOC) • Beam size 12x12 mm • Start beam Thursday 12 may 2011

20. Beam properties • Supercycle with 36x1.2=43.2 sec period • But sometimes is changing • Typical 2 bunches of 40 x 10 10 protons • But sometimes 3-4 bunches • Typical bunch positions: 4, 6,14,26 • Bunch length 400 msec • One iteration 2 (or 3) supercycles, 2-4 bunches per supercycle

21. Timing Problems • Syncronize with Spill signal instead of CPS cycle • Delete time stamps, DCS voltages and currents • Reduce readout to one DC per Spill • Result: able to readout without super-positions with the beam (except sporadic spills)

22. Timing Problems • Joern propose to write one RootDB file per spill, gain factor two in time • Since this weekend we switched to this mode • In this mode we have the time to double the readout and write the time stamp, so we can in principle correlate with beam information files • Software not yet ready for large volume analysis in this mode (handle of hunreds of files per run)

23. Measurement of beam profile by diode (Maurice Glaser)