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FGT cosmic ray stand: Combining hits to make tracks

Updated on Thu, 2012-08-30 18:22. Originally created by ramdebbe on 2012-08-19 17:58.

Aug 30 2012

I add more information to align the middle quadrant and see if we can find a transformation (translation and rotation) that will improve the overall resolution of the middle quadrant.

First the residual in phi as function of the phi of the space point in the middle quad:

 

 

Followed by similar plots for the radius variable:

 

 

In both cases the fits are performed only in the regions with the majority of entries which correspond to the scintillator trigger outlines.

 

AUG 28 2012

The following plots were obtained from runs 42 to 47. These events are the cleanest in that dataset; each quadrant has only two clusters (one R, one P). This dataset has 4471 events, the

complete dataset has 24404 events. With these clean events we define a line with top and bottom quadrants and compared the x and y coordinates of the intercept with the middle quadrant plane. The residuals in x and y for that quadrant are shown below as function of the x and y coordinate of the middle cluster:

 

 

 

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AUG 24 2012

I'm also adding the residual extracted for the middle quadrant (FGT007) using a line defined by the y coordinates of top and bottom points:

AUG 21 2012 22:50

Making a line with the points in the top and middle quads and extrapolating it to the bottom quad I can get a first idea of the residual quality:

 

The alignement in the y coordinate is fine and the width is a bit high, but my extrapolation is crude because I'm allocating no error to the cluster coordinates and we have not done any selection to use the most appropriate cluster finder criteria.

 

The next step is an attempt to estimate the efficiency of the bottom quad using two point tracks made with clean events that only have one pair of clusters (R and P) in the Top and Middle quads.

For such an event I then loop over the  clusters stored for the Bottom quad. This loop is a bit loose because I'm not checking that I have at least one R and P pair of clusters, but it will give me an idea of how active is the quad.

To estimate efficiency I fill the 2D histograms with coordinates in the Top and Middle quads for the clean single point events, extrapolate the line to the Bottom quad and impose a cut on y residual of 0.7 cm before I fill the corresponding 2D histogram.

TOP quad:

 

MIDDLE quad:

 

 Bottom quad:

 

The rough estimate of the efficiency of the bottom quad (FGT009) is 2408/3074 = 0.78

 This exercise could be done in a cleaner way imposing conditions on points in Top and Middle quads to be within the outline of the trigger scintillators and eliminate the spurious hits, but the result will only change slightly.

 

Aug 21 2012

I am writing the cluster information into a text file which I read later and form points. The easiest events are those which only have a pair of R and P clusters in all three quadrants. With those events I produced the following plots from runs 45,46,47 collected with same gas and HV as run 41, but using Gerard's latest configuration file.

The information from that pair of clusters is translated in local coordinates in the quadrant:

The quad I call disc0 is FGT009 sits at the bottom of the cosmic stand:

The outline of the scintillator is visible, aligned to the side of the quadrant with the APV board we are reading: see photo below:

 

First feature found in this figure is the band of "inefficiency"  from 31 to 33 cm in x.

 

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My disc1 is FGT008 located at the top of the cosmic stand:

This quadrant has the highest number of single R and P cluster pairs. It also shows well defined scintillator outline, and a narrow "inefficiency" band at x=29.

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The middle quadrant in the stand is FGT007  (disc2 in my notation):

The "inefficiency band is again present at x=29 cm. My first impression, without looking for details on the geometry of these detector, is that those bands do not correspond to actual detector features. My first guess is that HV sectors are defined by boundaries with constant radius.

 

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AUG 19 2012

I have been trying to use StFgtCosmicTrackMaker with StFgt2PointCosmicTrackAlgo but have been see any "points" out of the FgtCollection container.

A point is defined as a combination of two clusters; a R cluster and its related P (phi) cluster. In preparation to define my own "points" I looked at the "hits" (clusters) that can be found in the same container I have a list of the first 10 events of run 41 (gas 90-10 HV 3200V for top and middle quadrants and 3300V for the bottom one):

StFgtCosmicTrackMaker  point vector size 0 pointCollectionPtr  0xc04bbcc
StFgtCosmicTrackMaker  HIT 0 vector size 2 hitCollectionPtr  0xc04badc
StFgtCosmicTrackMaker  HIT 1 vector size 2 hitCollectionPtr  0xc04bb04
StFgtCosmicTrackMaker  HIT 2 vector size 2 hitCollectionPtr  0xc04bb2c
disc 0 r  29.358 phi 0.150674 layer R
disc 0 r  27.6341 phi 0.151968 layer P
Disc 1 r  31.0161 phi 0.149608 layer  R
Disc 1 r  27.7477 phi 0.109711 layer  P
Disc 2 r  29.9094 phi 0.150285 layer R
Disc 2 r  23.8799 phi 0.129385 layer P
Disc 2 r  24.2551 phi 0.0282166 layer P

event 1
StFgtCosmicTrackMaker  HIT 0 vector size 3 hitCollectionPtr  0xc04badc
StFgtCosmicTrackMaker  HIT 1 vector size 0 hitCollectionPtr  0xc04bb04
StFgtCosmicTrackMaker  HIT 2 vector size 0 hitCollectionPtr  0xc04bb2c
disc 0 r  24.1098 phi 0.155104 layer R
disc 0 r  23.6852 phi 0.313061 layer P
disc 0 r  27.6867 phi 0.130129 layer P
Disc 2 r  23.6813 phi 0.155603 layer R
Disc 2 r  23.6829 phi 0.309915 layer P

event 2
StFgtCosmicTrackMaker  HIT 0 vector size 7 hitCollectionPtr  0xc04badc
StFgtCosmicTrackMaker  HIT 1 vector size 5 hitCollectionPtr  0xc04bb04
StFgtCosmicTrackMaker  HIT 2 vector size 5 hitCollectionPtr  0xc04bb2c
disc 0 r  28.219 phi 0.151501 layer R
disc 0 r  27.7344 phi 0.151865 layer R
disc 0 r  16.3055 phi 0.166992 layer R
disc 0 r  27.8342 phi 0.473799 layer P
disc 0 r  27.8046 phi 0.465136 layer P
disc 0 r  23.9828 phi 0.0958785 layer P
disc 0 r  28.6875 phi -0.124586 layer P
Disc 1 r  32.7852 phi 0.148541 layer  R
Disc 1 r  18.3378 phi 0.162986 layer  R
Disc 1 r  28.2271 phi -0.00246032 layer  P
Disc 1 r  24.875 phi -0.156112 layer  P
Disc 1 r  25.0466 phi -0.161088 layer  P
Disc 2 r  31.61 phi 0.149258 layer R
Disc 2 r  30.4904 phi 0.14991 layer R
Disc 2 r  19.9484 phi 0.16032 layer R
Disc 2 r  16.1985 phi 0.167207 layer R
Disc 2 r  23.7441 phi 0.191573 layer P
Disc 2 r  23.9688 phi 0.0999449 layer P
Disc 2 r  24.5207 phi -0.0212932 layer P
Disc 2 r  28.3703 phi -0.0291178 layer P

event 3
StFgtCosmicTrackMaker  HIT 0 vector size 3 hitCollectionPtr  0xc04badc
StFgtCosmicTrackMaker  HIT 1 vector size 2 hitCollectionPtr  0xc04bb04
StFgtCosmicTrackMaker  HIT 2 vector size 2 hitCollectionPtr  0xc04bb2c
disc 0 r  29.5729 phi 0.150543 layer R
disc 0 r  24.8363 phi 0.154436 layer R
disc 0 r  23.6826 phi 0.25115 layer P
Disc 1 r  27.3417 phi 0.152166 layer  R
Disc 1 r  27.6341 phi 0.151721 layer  P
Disc 2 r  25.8417 phi 0.153457 layer R
Disc 2 r  27.541 phi 0.202876 layer P

event 4
StFgtCosmicTrackMaker  HIT 0 vector size 0 hitCollectionPtr  0xc04badc
StFgtCosmicTrackMaker  HIT 1 vector size 2 hitCollectionPtr  0xc04bb04
StFgtCosmicTrackMaker  HIT 2 vector size 2 hitCollectionPtr  0xc04bb2c
Disc 1 r  32.3289 phi 0.14881 layer  R
Disc 1 r  24.2353 phi 0.0319043 layer  P
Disc 2 r  32.3734 phi 0.14881 layer R
Disc 2 r  24.1971 phi 0.0407836 layer P

event 5
StFgtCosmicTrackMaker  HIT 0 vector size 0 hitCollectionPtr  0xc04badc
StFgtCosmicTrackMaker  HIT 1 vector size 2 hitCollectionPtr  0xc04bb04
StFgtCosmicTrackMaker  HIT 2 vector size 2 hitCollectionPtr  0xc04bb2c
Disc 1 r  32.3289 phi 0.14881 layer  R
Disc 1 r  24.2353 phi 0.0319043 layer  P
Disc 2 r  32.3734 phi 0.14881 layer R
Disc 2 r  24.1971 phi 0.0407836 layer P

event 6
StFgtCosmicTrackMaker  HIT 0 vector size 0 hitCollectionPtr  0xc04badc
StFgtCosmicTrackMaker  HIT 1 vector size 0 hitCollectionPtr  0xc04bb04
StFgtCosmicTrackMaker  HIT 2 vector size 0 hitCollectionPtr  0xc04bb2c

event 7
StFgtCosmicTrackMaker  HIT 0 vector size 0 hitCollectionPtr  0xc04badc
StFgtCosmicTrackMaker  HIT 1 vector size 3 hitCollectionPtr  0xc04bb04
StFgtCosmicTrackMaker  HIT 2 vector size 3 hitCollectionPtr  0xc04bb2c
Disc 1 r  32.0734 phi 0.148976 layer  R
Disc 1 r  28.1616 phi 0.151573 layer  R
Disc 1 r  28.6875 phi -0.090902 layer  P
Disc 2 r  31.953 phi 0.149031 layer R
Disc 2 r  24.875 phi -0.0806588 layer P

event 8
StFgtCosmicTrackMaker  HIT 0 vector size 3 hitCollectionPtr  0xc04badc
StFgtCosmicTrackMaker  HIT 1 vector size 2 hitCollectionPtr  0xc04bb04
StFgtCosmicTrackMaker  HIT 2 vector size 2 hitCollectionPtr  0xc04bb2c
disc 0 r  34.9115 phi 0.147443 layer R
disc 0 r  30.1451 phi 0.150158 layer R
disc 0 r  29.8988 phi 0.150349 layer R
Disc 1 r  29.6549 phi 0.150478 layer  R
Disc 1 r  27.7348 phi 0.113083 layer  P
Disc 2 r  32.0439 phi 0.148976 layer R
Disc 2 r  27.8025 phi 0.0940045 layer P

event 9
StFgtCosmicTrackMaker  HIT 0 vector size 3 hitCollectionPtr  0xc04badc
StFgtCosmicTrackMaker  HIT 1 vector size 0 hitCollectionPtr  0xc04bb04
StFgtCosmicTrackMaker  HIT 2 vector size 0 hitCollectionPtr  0xc04bb2c
disc 0 r  29.5729 phi 0.150543 layer R
disc 0 r  23.7201 phi 0.207396 layer P
disc 0 r  28.3703 phi -0.0283394 layer P

event 10
StFgtCosmicTrackMaker  HIT 0 vector size 2 hitCollectionPtr  0xc04badc
StFgtCosmicTrackMaker  HIT 1 vector size 2 hitCollectionPtr  0xc04bb04
StFgtCosmicTrackMaker  HIT 2 vector size 2 hitCollectionPtr  0xc04bb2c
disc 0 r  30.7345 phi 0.149788 layer R
disc 0 r  24.0119 phi 0.0868666 layer P
Disc 1 r  27.808 phi 0.151865 layer  R
Disc 1 r  23.9972 phi 0.0917598 layer  P
Disc 2 r  30.5011 phi 0.14991 layer R
Disc 2 r  28.2058 phi 0.151501 layer R
Disc 2 r  24.6744 phi -0.0482036 layer P

 

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