SVTMon (Online) Consumer

• List of histograms: Event histos, Track histos
• What to check

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List of histograms (click on links to get sample plots):

• Number of Tracks

1. Number of tracks found by the Track Fitter per event, summed over all wedges and barrels.
2. N. Tracks vs Event Trigger Number :
this plot has been added to monitor if at some point SVT loses syncrony with XFT track, if this happens N.Tracks becomes constatly zero. Also N.Tracks is put equal to -1 if the End Event word has not been found in SVTD bank (Read NOTE below in "End Event word found").
 
• SVTD Banks Found

1. Number of SVTD banks found per event.
2. N. of SVTD banks found as a function of Event Trigger Number.
 
• SVTD Bank Length

1. Number of words in SVTD bank.
2. Number of words in SVTD bank as a function of number of SVT tracks:

In the stable configuration SVTD bank has (6+7*(n.tracks)+1) words: the first 6 words are part of the bank header and should always be present, tracks info follows in 7-word packets (one packet per track), the very last word is the EE word (see CDF note 4152 , pg. 136 for details).


NOTE that for the moment a FIXED number of words (=200+6) is written into  SVTD bank, so for the moment this  two plots have little meaning.

• End Event word found

1. Number of SVTD banks with/without EE word
2. presence of EE word in SVTD bank as a function of Event Trigger Number
NOTE : a consequence of the fact that for the moment the number of words in SVTD bank is kept fixed to 200 is that events with more than ~25 tracks
appear to have no EE word because no room is left to write it in the SVTD bank.
Therefore,  for these plots,  do not worry if you see that sometimes EE is not found, instead do worry if EE word is not found, constantly !
 
• End Event Error Bits

This histogram is entered each time one of the error bits (bits 9:16) in the EE status word is set to 1. The meaning of the 8  bits is the following (see CDF note 4152 for details):

0 Parity error

1 Lost sync

2 FIFO overflow

3 Invalid data

4 Internal Overflow

5 Truncated output

6 G-link lost lock error

7 Parity error in cable to L2

• Chi2 folder:
1. Chi2, ALL Tracks
2. Chi2, barrel "n"  (in canvas "Chi2, barrels 0-5")
3. Chi2, wedges "n"  (in canvases "Chi2, wedges 0-5" and "Chi2, wedges 6-11")
Track chi-square value from the Track Fitter. NOTE that for the moment SVT does not apply  any chi-square cut, so all the histograms below are filled for every track candidate. The chi-square distribution is integrated over all wedges and barrels (1), is shown separately for each half-barrel but integrated over the wedges (2), and for each wedge but integrated over all half-barrels (3).
 
• D0

Impact parameter, in centimeters, with respect to the origin of the CDF coordinate system, for "good" (Chi2<CUT) tracks.The d0 distribution is integrated over all wedges and barrels. This is not the impact parameter with respect to the center of the beam, so large values are allowed if the center of the beam is shifted. Therefore this plot has no real meaning until beam has been aligned.

• Phi0 folder:
1. Phi0, ALL Tracks
2. Phi0, barrel "n"  ( in canvas "Phi0, barrels 0-5")
Track azimuthal angle, in radiants. The range is 0-2PI if all SVT wedges are in use (there should be no over/underflows). The Phi0 distribution is integrated over all wedges and half-barrels (first), and is available also separately for each half-barrel (second).

• D0 vs Phi0 folder:
1. d0 vs phi0, ALL Tracks
2. d0 vs phi0, barrel "n"  (in canvas "d0 vs phi0, barrels 0-5")
3. d0 vs phi0, barrel "n": Chi2 < CUT  (in canvas "d0 vs phi0, barrels 0-5: Chi2<CUT")
Impact parameter vs phi angle for all  SVT found tracks, and tracks  with good Chi2 (chi2 of track fit performed by Track Fitter boards).
These are the basic plots to check for beam alignment. Also, these plots allows to see if the Track Fitter finds tracks that make sense. If the beam spot has coordinates (x0,y0) in the transverse plane and all tracks come from that point, there is the following relationship between d0 and phi: d0=x0*sin(phi)-y0*cos(phi). If the beam is perfectly aligned, then d0=0 for every phi. The presence of reasonable tracks is shown by the fact that most of the points in the plot are concentrated along a sine wave.
 
• Curvature

Curvature in inverse centimenters for all "good" (Chi2<CUT) tracks. The range is +-0.003, which corresponds to a minimum Pt of about 0.7 GeV.
 
• Pt

Absolute value of transverse momentum in GeV, for "good" (Chi2<CUT) tracks in all SVT sectors. Remember that SVT , when running in the "Silicon+XFT " stable configuration reconstructs only tracks with Pt above about 2 GeV.
 
• Sectors Occupancy  (IN and OUT)

Total number of tracks found in each wedge  which enter ("IN") or exit ("OUT") a given half-barrel (NOTE : SVT has a total of 12*6=72 half-barrel, wedge slices called "sectors").  Differences between the "IN" and "OUT" plots are due to tracks which go across two barrels (NOTE : tracks can only cross two adjacent half-barrels placed in the same wedge). These two plots are presented as lego plots (X=wedge, Y=half-barrel) and can be rotated using the mouse (a ROOT feature!).
The information is basically the same as in plots "Wedge  Occupancy, barrel  'n'" below.
 
• Barrel Occupancy  (IN and OUT)

Total number of tracks in each barrel (all wedges). NOTE :  the "IN half-barrel" is the half-barrel where the track crosses the inner SVT Silicon Layer (tipically SVX layer 0), the "OUT half-barrel"  is where the track crosses the outer SVT Silicon layer (tipically SVX layer 3). Differences in these two plots are due to tracks which go across two barrels. NOTE : half-barrel are numbered 0-5 west to east, therefore half-barrels 2 and 3 are the central ones (low eta).
 
• Wedge Occupancy folder:

1. Wedge Occupancy, ALL Tracks
2. Wedge Occupancy, barrel "n" (in canvas "Wedge Occupancy, barrels 0-5")

Number of tracks found in a given wedge (0-11). NOTE : the histogram's content  increases with the number of the events, this is not the average number of tracks per event in a wedge). This is shown inclusively (first) and per each half-barrel (second).

• Patter Occupancy  (A and B)

Distribution of the "road" number, i.e. the total number of tracks found in a given pattern.The distrubution is shown separately for A and B patterns: A-type patterns correspond to even wedges, B-type patterns are for odd wedges. The range is 0-32768; distributions for A and B should be similar.

• Hit occupancy

The histogrammed quantity is the content of the 8 Least Significant Bits of the hits coordinate in SVT Silicon layers 0-4, in units of 16th of strip. The distribution should be uniform in the range 0-256 if the Si layer is used by SVT, otherwise the histogram should be empty.

• Fit Quality folder:
1. Fit Quality, ALL Tracks
2. Fit Quality, wedge "n"  (in canvases "Fit Quality, wedges 0-5" and "...wedges 6-11")
Distribution of the content of bits 0-3 of Track Fitter Status Word. The documentation explaining the meaning of this quantity can be found in CDF note 4152 and CDF note 5026. The plot is made for tracks in all wedges (1), and also for each wedge separately (2).

• Track Fitter Status folder:
1. Track Fitter status
2. Track Fitter status, wedge "n" (in canvas "Track Fitter status, wedges 0-5 " and "....6-11")
Track Fitter error bits are decoded (are bits 5:11 of the TF Status Word).
This plot is done for all the tracks (1) and also for each wedge separately (2).
The meaning of the 7 bits is the following (see CDF note 4152 for details):
0 Hit overflow (i.e. more than 7 hits in one superstrip)
1 Layer overflow (i.e. too many layers with multiple hits)
2 Combinations overflow (i.e. too many combinations for fit)
3 Invalid data (i.e. hit out of order, not enough SVT hits)
4 Fit Overflow (i.e. fit result in XFT part is overflow)
5 FIFO overflow
6 OR of the above bits

• XFT linked track folder:

1. XFT linker number, ALL Tracks
2. XFT linker number, barrel "n" (in canvas "XFT link number, barrels 0-5")
3. XFT Track Correlations

This folder collects information about XFT linked tracks, i.e. XFT tracks associated to Si hits and fit together into the SVT tracks.

XFT linker number is the 9 Most Significant Bits of the phi6 coordinate of the XFT track as delivered to SVT by XTRP, i.e. the XFT mini-wedge number. The size of the mini-wedge is about 22 mrad (there are 288 mini-wedges in total). XFT reports one track per wedge at the most, so this number uniquely associates the SVT track to the original XFT one.

1. XFT numbers distribution is integrated over all wedges and barrels

2. XFT numbers distribution is also given separately for each half-barrel and integrated over all wedges.

3. phi0 and abs(Pt) distribution of XFT linked track. But...more important are the correlation shown of these two quantities with phi0 and curvature of the associated SVT track.

• Number of SVT tracks:

is the histogram empty? Is the number of tracks always 0 ? Is the average number of tracks different from the reference plots?
 
• Chi-square:

is there any chi-square cut? Is the position of the peak too far from 0 ? (it should be < 10)
 
• Phi:

is there any hole/peak in the distribution? Missing wedges?
 
• Wedges/Barrels/Sectors occupancy:

is any wedge behaving differently? Check the plots relative to a given wedge/barrel. Check for any unphysical value for the wedge or barrel number (histogram overflows/undeflows).
 
• d0 vs phi0:
1. can you see a sine wave? Are there many points outside the sine wave? Is there any structure overlayed to the the sine wave?
2. Check d versus phi for different half-barrels. If the plots look different, it means the is a beam tilt along z.
3. How to make a beam position fit by just looking at the d versus phi plot (in polar coordinates): the maximum and the minimum d on the sine wave is the value of rho of the center of the beam; the value of phi at which the sine wave crosses the phi-axis with positive derivative is theta. You may convert to x,y , compare with other fit results and see how good you are.
4. You can do the fit in more than one half-barrel and check for any beam tilt along z.