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daq:mode2 [2012/05/18 14:28]
campbell S
daq:mode2 [2014/02/27 16:14] (current)
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 +====== DAQ:Mode 2 data loss (Chris) ======
 +
 ====== Severity ====== ====== Severity ======
-We cannot afford losing any triggered data. For absolute x-section ​measurement ​GRETINA efficiency is crucial. +We cannot afford losing ​<del>any triggered</​del> ​data //**in an uncounted manner**//. For absolute x-section ​measurements with GRETINA efficiency is crucial.
  
 ====== Problem ====== ====== Problem ======
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        ​719 ​   s800 only events        ​719 ​   s800 only events
        ​15 ​    ​gretina only events (now fixed in S800 daq)        ​15 ​    ​gretina only events (now fixed in S800 daq)
 +       
 +  So, ~6% of the decomposed data is missing.
 +  ​
 +  Also, missing gretina data is spread throughout the file, not concentrated at the beginning or end.
  
 ====== Progress ====== ====== Progress ======
 +  * 5/17/2012: Discussed losses with Mario. ​ Code review and version check to follow.
 +  * 5/24/2012: (kathrin) checked runs 694 (old decomp) and 697 (new decomp) taken on 05/22
 +
 +    coincidences = s800 and gretina GGEB header with time stamps within 1000 ticks
 +    s800 singles = missing gretina GGEB header and event
 +    gretina singles = no s800 in this event
 +    decomp fails = error in decomposition,​ "​pad"​ of gretina struct is != 0 (I get errors 3 and 5 see below)
 +     
 +    Run 694:
 +        172171 coincidences (94.4 %) 
 +        10207 S800 singles (5.6 %) 
 +        18 Gret singles (0.0 %) 
 +        0 Decomp fails (0.0 %) 
 +     
 +    Run 697:
 +        97888 coincidences (91.2 %) 
 +        9477 S800 singles (8.8 %) 
 +        0 Gret singles (0.0 %) 
 +        81 Decomp fails (0.1 %) 
 +        ​
 +    decomp fails are included in the coincidences (since they have a valid time stamp), as error I get 3 and 5.
 +    in both cases the event is completely empty (everything is zero) except for the crystal_id.
 +    out of the 81 failures I have 54 error 3 (no net charge segments) and 27 times error 5 (bad chi^2)
 +    ​
 +this test has to be repeated, to me it is completely unclear, why run 694 has again S800 problems (these were thought to be solved before)
  

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