FGT (FEE and) Readout/DAQ
Status and issues from operations perspective
Gerard Visser
FGT Meeting
April 16, 2012
General status is ‘ok’ – but deficiencies exist
• Most runs run smoothly, under control of shift crew
• Deadtime is now pretty low, e.g. ~2% @ 250 Hz 
• We’ve run 7 timebins, non-ZS for the whole run 12
• Event size 208 kB, is a lot (TPX ~1MB)
• We better use 7 timebins in analysis, we may not get this next year!
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• 1100 token limit†
Can control all FGT-relevant APV parameters and all timing
parameters
Can read temperatures of FEE but only when not in run;
currently only done at configuration time
Version control used for ARM firmware (svn), ARC firmware (?),
DAQ/control software (CVS)
No known hardware failures in crate, HVPS, ARM, or ARC in
run 12 (maybe something in test stand)
Modularity was exercised on several occasions with module and
cable swaps in short accesses
Remote firmware updates applied successfully
ARC patches and buffer size limit point to need to revise ARC
for run 13+
†The
1100 token limit is purely my fault for way
underestimating event size 2 years ago.
Run 12 issues – FGT Meeting April 2012
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(Probable) FEE issues
1.
We need to now look at and discuss
http://drupal.star.bnl.gov/STAR/system/files/STAR_Cosmic_Analysis.pdf .
It looks to me like the issue is far from closed...
2.
3AB group is generally not working due to I2C hardware problem.
3.
After 3/31/2012, 4AB group is not working, suspect voltage regulator
failure, pedestals have gone crazy. Trouble started with Gerrit’s high rate
running, but that’s probably just a coincidence.
4.
Many flaky APV chips, e.g. 7 in run 13105023. I don’t think it’s
understood. It doesn’t look like a failure of configuring the APV, since
readback is generally ok.
Run 12 issues – FGT Meeting April 2012
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13105023 RTS Start Sat Apr 14 09:18:46 EDT
• lots of variation in
saturation level?
• some ADC “above
saturation”? is it some
timebins saturate
before others?
• all that stuff below
pedestal definitely
concerns me
• is all the above
“normal behaviour of
APV chips?” or is there
something wrong in
our application of
them?
• IST test stand will
provide a point of
reference. Can we run
Jplots on that data?
Run 12 issues – FGT Meeting April 2012
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13105023 RTS Start Sat Apr 14 09:18:46 EDT
whole APV waveform is low
amplitude, could it be a
cable/connection issue?
(did we ever swap ARM on this?)
Incidentally, it looks like gain is simply not balanced? 2A much higher gain than 2B?
Run 12 issues – FGT Meeting April 2012
5
13105023 RTS Start Sat Apr 14 09:18:46 EDT
I2C line hardware problem on cable/FEE,
looks like it is shorted low
Run 12 issues – FGT Meeting April 2012
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13105023 RTS Start Sat Apr 14 09:18:46 EDT
the van Nieuwenhuizen effect?
Run 12 issues – FGT Meeting April 2012
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13105023 RTS Start Sat Apr 14 09:18:46 EDT
?
“Ouch! Who stepped on my dynamic range?”
It might be interesting/useful to compare
waveforms between say 5AB[640:767] and
5AB[0:127]
Run 12 issues – FGT Meeting April 2012
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13105023 RTS Start Sat Apr 14 09:18:46 EDT
What’s this?
Run 12 issues – FGT Meeting April 2012
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Waveforms in FGT – discuss
• above is from http://drupal.star.bnl.gov/STAR/blog/leun/2012/feb/08/fgt-timing-scan-02082012,
run 13039071 – it’s the last I’ve heard about waveform data in FGT
• a lot of variation in pulse shape (and I don’t show any pathological cases here)
• a lot of these probably are saturated though – any more recent plots we can look at?
• speaking of saturation, is that destroying our R-φ charge correlation? it could be...
Run 12 issues – FGT Meeting April 2012
10
Readout system issues
1. Failure on run start. (Silence from one or sometimes both RDO’s) This problem
has always been with us.
2. Failure after running (usually 5-20 min)†. Sometimes one, often both RDO’s. This
has been a real nuisance.
3. Occasional avoidable extra trouble and confusion for the shift crew stemming
from the 1100 token limit. This has been seen due to runaway calorimeter trigger
rates (due to SEU) and due to operator error (e.g. including FGT in normal
pedAsPhys run).
4. Hopefully, heightened awareness by the crew, assisted by more thorough
highlighting of errors and more automated configuration and recovery, will cut
back on the amount of beamtime wasted owing to the various FGT readout
problems. But, we need to do much better next year, this has been a
disappointment and embarassment and has had nonzero costs to run 12.
5. There are also numerous troubles specific to the test stand setup, which is a bit
of a hack and has (firmware) diverged from the actual STAR setup. I need to
refocus effort to synchronize that with STAR setup, resolving these issues as
well of course. Tomorrow’s main task...
†There
is some confusion (at least on my part) whether this started after busy changes or was
present from day one. Also, given the location of readout crate I am skeptical that it is an SEU
issue. Not impossible though.
Run 12 issues – FGT Meeting April 2012
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