s. durkin, uscms-emu meeting, oct. 21, 2005 critical data errors s. durkin the ohio state university...
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Critical Data Errors
S. DurkinThe Ohio State University
USCMS EMU Meeting, FNAL, Oct. 20, 2005
Data Errors – A HistoryData Errors – A HistoryData Errors in 2004 Test Beam were the Dominant Problem
• DQM Crashes, DDU reports critical errors• How healthy is the electronics?
• DMB-TMB LCT time delay missing • Impossible to time in DAQ (Experts: don’t worry!)
September 2005 Slice Test
• full Peripheral crate of production TMB, DMB, CCP, MPC• FED crate with production DDU/DCC• missing new Crate Controller, Final LV supplies
• DMB block recycle increased to accommodate large Latency• DMB-TMB LCT delay kludged in DMB firmware UCLA must be added permanently to TMB firmware
Additional problems uncovered in Sept05 Slice Test
• CFEB L1A# ambiguous in overlap events (2 events/block)• word count overflow for ALCT time bin data (header size too small) • gigabit driver memory ring wrap around
Vindication 1 million event error-free runs!
Data Errors – Gone!Data Errors – Gone!
Preliminary Slice Test Track Fitting S. Durkin Sept. 8, 2005
Analyze RunNum1007Evs0to49999.bin using /AnalysisUtilities
• look for tracks in two separate CSC’s• trigger very loose, 9291/50000 such events found• single overall cross talk and noise constants used• events typically very well fit (see next two pages)• analyze data with CSC5 and CSC9 hit.
CSCID Chamber Type 4 ME2/1 16 no data 5 ME2/2 31 7 ME2/2 32 8 ME3/1 16 no data 9 ME3/2 31 10 ME3/2 32
CSCID1 CSCID2 Events 5 7 636 5 9 3129 5 10 1423 7 9 994 7 10 2326 9 10 670
Red Events chamber overlap.
************ Event ID 38 CSC ID 5 CSC type 0 Cathode Tracking: Number of Tracks 1
Track 0 Plane 0 Hits 0 y 61.8693 dy 0.07552 dif -0.0715 used Plane 1 Hits 0 y 61.2128 dy 0.02231 dif 0.0251 used Plane 2 Hits 0 y 60.6817 dy 0.00702 dif -0.0037 used Plane 3 Hits 0 y 60.1169 dy 0.01132 dif 0.0012 used Plane 4 Hits 1 y 59.5459 dy 0.01219 dif 0.0123 used Plane 5 Hits 0 y 59.0460 dy 0.03158 dif -0.0477 used
Cathode Track Fit (4 DOF) for track 0: Slope -0.55990 Intercept 61.7978 Chisqr 5.752332
Typical Track – Evt 38 CSCID 5 (Near Side)
Distance from track in Strips.Typically < 200m
************ Event ID 38 CSC ID 9 CSC type 0 Cathode Tracking: Number of Tracks 1
Track 0 Plane 0 Hits 0 y 36.5085 dy 0.00424 dif 0.0006 used Plane 1 Hits 0 y 36.0551 dy 0.00995 dif -0.0662 not used Plane 2 Hits 0 y 35.4979 dy 0.01635 dif -0.0292 used Plane 3 Hits 0 y 34.9292 dy 0.01200 dif 0.0194 used Plane 4 Hits 0 y 34.4546 dy 0.01630 dif -0.0261 used Plane 5 Hits 0 y 33.8762 dy 0.02779 dif 0.0321 used
Cathode Track Fit (4 DOF) for track 0: Slope -0.52015 Intercept 36.5090 Chisqr 9.727195
Typical Track – Evt 38 CSCID 9 Far Side
Cathode Strip Angle Matching
Black Curve – CSC5 Red Curve – (CSC5 minus CSC9 )
• Compare track angles• Ignore any geometry corrections
CSC9 (degrees)
CS
C5
(de
gree
s)
Nu
mbe
r o f
Eve
n ts
(degrees)
~ 4 degrees
Cathode Strip Intercept Matching• Extrapolate track intercept• Ignore any geometry corrections except for Z position• Note: CSC5 and CSC9 are back to back (mirror images)
CS
C5
plu
s C
SC
9 In
terc
ept
(str
ips)
CSC5 Slope
Black Curve – CSC5 InterceptRed Curve – CSC5 and CSC9 Corrected Intercept difference
Nu
mbe
r of
Eve
nts
Intercept (strips)
~ 2.5 strips
Best Fit DistanceBetween Chambers 101cm
Anode Wire Angle and Intercept Matching
• Anode tracks (units of wire groups) • Ignore any geometry corrections except for Z position
CS
C9
(d
egre
es)
CSC5 (degrees)
CS
C5
min
us
CS
C9
Inte
rcep
t (w
ire
grou
p)
CSC5 Slope
Cathode Strip Expected Resolution
• covariance matrix from the least-squares fits to the track can be used to estimate angular error and extrapolation error• using PDG notation
D/222 2
111211112 )/100(//1 Dposition
edextrapolat
• from the data- angular error 0.15 degrees extrapolated position 0.6 strips
Multiple Scattering Dominates
• from the particle data group it is easy to calculate
)(
5
cGeV
o
scatmult P
Real Time DDU MonitoringReal Time DDU MonitoringDDU/DCC Monitoring Controls Detector Resets Run Control: 1) reset initializes electronics 2) start DDU monitoring 3) take data
Continuously read DDU status register
Software Reset of Emu System on error (approx 200 sec)
FMM Reset from computer write to VME register
Firmware Real-time resets also possible (approx 30 sec)
• Spy Data DQM Superfluous, Monitoring done “real time”• DDU traps ALL critical errors in 25-100 sec and requests FMM reset
DDU Error CheckingDDU Error Checking
1 million events 16 Gb~ 16 seconds LHC running
LHC DDU/DCC OccupancyLHC DDU/DCC OccupancyHow well have we checked “real time” error detection?
Conclusion – Need More DataConclusion – Need More Data
Slice Test: 112K events(1 LHC sec) takes a 5 minutes run.
112:1
30 days running yields 6.4 LHC Hours
Data taking should be left on 24/7.Shifts are not necessary. No additional risks.
To Reset or Not to Reset:Rare Hardware failures have to be understood.
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