Status of measurements of FE-I4 SEU and PRD

P.Breugnon, M.Menouni, R.Fei, F.Gensolen, L.Perrot, A.Rozanov,

08.06.2011

GR errors at start of run and Malte’s On-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

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

Classification of GR

• 1)PRDlike resets: All read GR bits zero, ServiceRecord non zero if SR read placed after GR configure. Thanks Maurice for pointing to it. SR21~100, SR24~0, SR25~0

• 2)Write glitch from Decoder: One bit flip in GR, ErrorFlagb(SR24)=0, WrRegDataErr(SR25)>0

• 3)Internal glitch in Global Memory: One bit flip in GR, SR24=0,SR25=0

• 4)Normal GR SEU: one bit in GR is flipped, SR24>0, SR25=0• 5)Efuse errors: same type of SEU hard triple memory, but reset and

some logic with ARM cells, reload to GR from PROM (actually 0) if single SEU bit flips in triple memory(actuallu with the bug).

• 6)”Frozen” bits in 16 words, SR24=16, SR25=0

PRD-like GR errors

• Biggest effect in GR errors, SEU hard triple memory probably not responsible

• Typical rate with GR configure in every spill is 5.3 % (79/1480 spills)

• In majority of cases SR21~100, SR24=0, SR25=0/2• 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 on doubled reset lines ?

PRD-like GR errors, run83, chip 28

PRD-like GR errors, run 83, chip#28

PRD-like GR errors, run 83, chip#28, 39 events

No GR errors, run 83, chip#28, ~700 events

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 0.7% (11/1480 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 ?

Write glitch from Decoder run 83, chip#28, 3 events

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 0.7% (10/1480 spills)• On top of Triple Memory Cells there are some

SEU non-hard logic. Is it responsible for these glitches ?

Internal Global Memory glitch, run 83, chip 28, 3 events

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 0.1% (2/1480 spills)• Too high, as the experimental rate of single SEU SR#24 is

6.8%, we gain with triple latches only a factor 70. Naïve extrapolation in absence of correlations predicted rate is ~0.003 %. Could the correlations give the worsening factor of 30 ?

Efuse GR errors

• SEU hard triple memory, but logic around in ARM cells and reload from PROM in case of latch SEU

• Typical rate with GR configure in every spill is 0.4 % (5/1480 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/without correction

Efuse GR Write errors, run 83, chip #28, 2 events

Scotch bits in run 83 , chip#27• After iteration 29, abnormal scotched bits appeared• SR#24=16 always, SR#25=0• many words got wrong static error, not erasable by GR configuration, cold start helps• ERRMASK1: 65535 0• DISVBN_CPPM: 62 0• PRMPVBP: 0 8• LVDSDRVIREF: 171 26• BONNDAC: 237 25• PLLIBIAS: 88 0• LVDSDRVVOS: 105 0• PLSRLDACRAMP:64 255• PLSRVGOAMP: 255 0• VTHIN_ALTFINE:128 0• COLPR_MODE: 1 0• COLPR_ADDR: 0 8• CHIP_LATENCY: 210 0• KILLDC38: 0 1• KILLDC36: 0 1• KILLDC35: 0 1• CMDCNT0_12: 11 0• LVDSDRVSET06:1 0• CLK0_S2: 1 0• EN_160M: 1 0• RISEUPTAO: 7 0•PULSERPWR: 1 0•PULSERDELAY: 2 0•EXTDIGCALSW: 0 0•EXTANCALSW: 0 1

GR error rates, run 84, chip#28 , 750 spills

Summary GR error rates

• average runs 75,81,83 chips#27 and #28• PRD-like GR errors 5.3 % (79/1480 spills) • Write from Decoder 0.7% (11/1480spills)• Internal GlobalMem glitch 0.7% (10/1480 spills)• GlobMem SEU 0.1% (2/1480 spills)• Efuse (Write) 0.3 % (4/1480 spills, 3 times less bits)• Efuse (Int) 0.1 % (1/1480 spills, 3 times less bits)

Preliminary PR 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

Normal SEU chip #27, run 52,

DC29- 0ld DC30 -new

Vdda=1.5V-0.1V

Normal SEU chip #27, run 52,

DC28- 0ld DC31 -new

Vdda=1.5V-0.1V

SEU asymmetry

• run 54, chip 27, Vdda=1.4 V-0.1V, 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

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

Conclusions

• Abnormal high PRD rates: calibration of PRD or reset glitches ?

• Too high Write decoder rates.• Too high Internal Global Memory glitches• Good single latch SEU rate ~6%• High Triple Global Memory. Correlations ?• One abnormal run with some scotched GR bits. • New/old pixel SEU latches verified also in DC28/DC31: much

better performance of new latches • 0->1 versus 1->0 SEU asymmetry opposite in new PR latches• More runs at PRD/GR position agreed for this week

Spare

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

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

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)

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)

Measurement of beam profile by diode (Maurice Glaser)