FA125 Update February 11, 2016

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Location and Time

Room: ?

Time: 2pm.

Remote Connection

You can connect using BlueJeans using the meeting number 589 693 655 .       (Click "Expand" to the right for more details -->):

(if problems, call phone in conference room: 757-269-6460 might not be the correct number)

  1. To join via Polycom room system go to the IP Address: 199.48.152.152 (bjn.vc) and enter the meeting ID: 589693655.
  2. To join via a Web Browser, go to the page [1] https://bluejeans.com/589693655.
  3. To join via phone, use one of the following numbers and the Conference ID: 589693655
    • US or Canada: +1 408 740 7256 or
    • US or Canada: +1 888 240 2560

More information on connecting to bluejeans is here

Specific instructions for connecting via polycom:

  • Turn polycom on if necessary
  • With the polycom, place a call at 199.48.152.152
  • Press # to enable the polycom keypad, then enter the meeting id: 589693655 and #
  • You may have to unmute the microphone: #*4
  • Turn the computer on if needed

Agenda



Minutes

Present: Naomi, Mike (CMU), Beni, Cody, Fernando, Lubomir, Eugene, Luke, Chris, Nick, Simon, Sergey (JLab). This followed on from the tracking meeting.


Cody loaded a new version of the firmware onto the CDC crates last night but unfortunately Beni found some problems with it this morning. An error in the state machine had been introduced when fixing the end of window condition for the integration and peak search. Cody will fix this and recompile and load the new version (2.0.8). The changes since the previous version have addressed the differences listed in FA125_firmware_check#Differences_in_data.2Femulation_from_run_4062 and also have removed the 13th bit from the overflow samples. This bit was previously set when the sample value was 4095. The firmware overflow count looks for sample values of 4095 so we do not need the separate overflow bit. Removing this allowed the samples to be represented by 1 bit less throughout the firmware and we hope this might help reduce overheads and improve timing. (Another change noted previously was that the peak search with the sample containing the leading edge time. If that sample is after the end of the hit search window, return integral=0 and amplitude=last sample in hit window.) He also removed chipscope from the processor chip.


Naomi's comparisons between CDC firmware and sample data show differences in approx 30 hits per million. Apart from the known differences listed above, it looks like these are due to timing issues. Naomi also looked at FDC firmware emulation and was alarmed to find a much higher error rate until Beni remembered that the CDC firmware dates from Dec 4 but the FDC crates have the older firmware version, from Nov 13. There are far more evio errors with the CDC than the FDC firmware. Beni has not found any FDC errors at all. (Beni wrote his own EVIO decoder, Naomi uses a simrecon plugin).


Naomi found one more run file with corrupt fa125 data which made simrecon crash, David has made a fix for this.


There are many instances where window raw data disappear when all the CDC channels fire. Beni and Cody already found last week that this is because the readout list in CODA is not reading out enough words. The remaining words in the fadc which are not read out corrupt the following events. Naomi asked if Sergey could increase the number of words read out. Sergey said that CODA displays an error message when this happens. Beni will talk to him more about it. The all-chamber events are when there is a signal in every channel in the CDC, the signals are real (not noise) although not every signal comes from a track (the strawless channels also show signals above threshold). Fernando pointed out that this is not due to crosstalk, it is just that a giant signal causes a dip in the HV on the card and the AC coupling shares out the dip over all 24 channels. There are only 150 HVBs so this can happen with a large cosmic shower.


Naomi has made a long table listing most of the missing data events FA125_firmware_check#EVIO_problems from the later runs with the correct DAQ settings blocklevel=1 and bufferlevel=1. During the massive events (3000 + hits) data is missing from the last channel in a slot and probably from the later channels in the same slot. There are also several hits with missing samples from a channel in the middle of a slot's readout and with not many hits in the event.


After the meeting Beni looked at 2 events where Naomi had found 1 improbable sample missing, run 4715 event 1041808 and run 4746 event 2359304. Beni's scanner shows that the correct number of samples are present in the evio file - but the last one has its invalid-sample bit set.



Useful Info

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