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BaBar L1 Trigger Monitoring



Back to [BaBar] [Electronics] [Trigger] [Level 3] [LBL Trigger] [RAL Trigger]
Contents: [TOP] [L1 Trigger monitoring] [EMT (L1) monitoring] [DCT (L1) monitoring] [GLT (L1) monitoring] [FCT (L1) monitoring]

L1 Trigger Monitoring

  • Data Quality Plots: Recent runs
  • Data Quality Archive: All runs


  • Reference Plots can be found here.

    Documentation on PS-files:

    GLT (L1):

    page 1: Global Trigger (GLT) Timing

    -> look for good overlap in ticks
    -> tick range should be fully contained within lower and upper edges
    (1) GLT Input Lines (9) Timing (16 ticks)
    (2) Object Count (17) Timing (16 ticks)
    (3) GLT Raw Output Lines (24) Timing (32 ticks)

    page 2: GLT and FCT Trigger Lines

    (1) Raw Trigger Line distribution
    -> depends on Trigger configuration
    Overlayed in red is the scaled (or FCT) Trigger Line distribution.
    -> From Line 1 to 15 the red and black curve should be identical. Beyond 15 are the scaled lines and
    the red curve is below the black one. The last two lines 23 and 24 are not used in the trigger
    and should be at zero (they only have background- monitoring purposes).
    (2) Ratio of GLT and FCT Trigger Line Distributions
    The scaling factors drop out in the ratio. The unscaled lines should be at one. For the other
    lines, the scaling factors depend on the trigger configuration, typically about 10%. With increasing
    line number the suppression gets stronger.
    (3) Number of GLT(!) Trigger Lines per Event
    -> Events with zero GLT triggers are shown in green. These come from 4 external trigger lines (usually
    bunch-crossing or cyclic trigger)

    page 3: GLT-FCT-DCT-EMT Interface Tests

    -> look for red damage bits
    (1) GLT Input-Output Test compares Input Phi-Maps with GLT Output Trigger Lines.
    (2) DCT-GLT Cable Errors
    -> Right now there is a not understood software problem. Ignore the bits.
    (3) EMT-GLT Bit shows ROM dataflow damage.
    (4) GLT-FCT Error Bit shows number of FCT triggered events without the corresponding GLT Line set.
    (This should never happen. Every FCT Line must have a GLT counterpart.)
    It is ok when 1-2 Error Bits are set in histograms (1) or (3). These come from Synch's which are a normal start
    of any run. Histogram (2) contains typically thousands Error Bits and should be ignored.

    FCT (L1):

    page 4: GLT and FCT Trigger Line Correlations

    (1) GLT-FCT Correlation plot
    (2) Distribution of unique FCT Trigger Lines. Events were triggered by only one trigger.

    DCT (L1):

    page 5: Track Segment Finder (TSF)

    (1-10) Hit Occupancy Maps (10 superlayers)
    -> look for spikes and holes
    Holes may be caused by local HV problems in DCH segments. Check first with the DCH expert the HV status
    of the DCH segments in question. Superlayer 6 has a known HV problem. Currently the whole chamber is affected
    by HV problems.
    Spikes are usually not related to the DCH, but indicate, due to the correlation in the trigger, a hot tower in the
    EMC. Check the EMT plots on page 7 and 8 for hot EMT towers. A structure in the Occupancy Maps reflects
    the angular distribution of backgrounds, dominantly in the horizontal plane.

    page 6: PT-Discriminator/Track Linker (PTD/BLT)

    (1)(2) CellNumbers with Track Segments used as Seed for PT Discrimination
    (1) in superlayer 10 and (2) in 7.
    -> look for holes or spikes
    (3)(4) Phi-maps of A and B tracks.
    -> look for holes or spikes

    EMT (L1):

    page 7: Calorimeter Trigger (EMT)

    (1) Output Map M: M trigger primitives sent to the GLT. These are raw counts of the number of times the M
    'fires' in each phi strip. Look for holes or very large peaks out of proportion with the neighbouring strips.
    (2) Output Map M V time: A timing plot of (1).
    The peak should be centered around tick 17. They should all line up.
    (3) Theta V Phi: This shows the distribution of hits in the calorimeter towers. This plot is good for showing
    "hot" towers. These are displayed as boxes which are much larger than their neighbours. If this is noticed
    inform the EMT expert. A white space means the tower is masked out.
    (4) Same as (3) but with an energy cut of 100 MeV. Typically hot towers
    come out more directly here. The difference to the neighbour towers is more pronounced.

    page 8: Calorimeter Trigger (EMT)

    (1)(2)(3) Plots of Energy deposits in the EMT with a cut of 100MeV in different theta-regions
    of the calorimeter. There are three polar angular regions distinguished:
    Phi = everything, Y = encap, X = backward barrel.
    (1) Phi - (X+Y) = central part
    (2) X = backward barrel
    (3) Y = forward endcap
    Hot towers appear as peaks in these plots. You may tell the trigger experts where you observed
    the hot tower. You also will see holes in these distributions. They correspond to masked out channels.
    (4) Average Phi Energy per strip

    page 9: Calorimeter Trigger (EMT)

    (1) EMT phi energies vs time in all strips: Hot towers typically show up as horizontal bands at unphysical energies. 1 count = 0.4 MeV
    (2) EMT average Phi Energies

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    Contact Sibylle Petrak via e-mail sibylle@slac.stanford.edu or Anders W. Borgland