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Revision as of 21:43, 9 September 2016
Vertex Reconstruction studies
Inclusive electron GEMC 2.4 & Coatjava 2.4
Summary
Set all histogram ranges to -6,6 cm and bin sizes of 0.1 cm
Point target X,Y,Z=0 cm
Below are examples of the reconstruction for several line targets as seen in the CED
We should change it to +30,150,210, and 330 degrees so the electron is not going in between two drift chambers but rather into the center, keep 90 and 270.
| 6cm Z Target, No Rotation | 6cm Z Target, 270 Degree Rotation | 6cm Z Target, 90 Degree Rotation | 2cm Y Target, 30 Degree Rotation | 2cm Y Target, 180 Degree Rotation | 2cm X Target, 90 Degree Rotation | 2cm X Target, 270 Degree Rotation |
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The histograms below are using a 6 GeV electron fired at an angles of 25 degrees in theta and 0 degrees in phi.
| No Rastering | |
|---|---|
| Vx Difference | 
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| Vy Difference | 
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| Vz Difference | 
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| X Resolution (cm) | 0.2362 +/- 0.0008 |
| Y Resolution(cm) | 0.09809 +/- 0.00033 |
| Z Resolution (cm) | 0.05435 +/- 0.00017 |
These histograms raise some questions. To begin I created a LUND file with 6 GeV incident electrons at 25 degrees in theta and 0 degrees in phi. All of the vertex positions were set to 0. I then ran GEMC 2.4 using the command line ~/src/CLAS/GEMC/source/gemc -USE_GUI=0 -INPUT_GEN_FILE="LUND,No_Raster.LUND" -N=75000 eg12_sol_No_Raster.gcard
which created an output file called eg12_sol_75k_No_Raster.ev. After that the reconstruction command line used was
~/src/CLAS/coatjava-2.4/bin/clas12-reconstruction -i eg12_sol_75k_No_Raster.ev-config GEOM::new=true -config MAG::torus=-1.0 -config MAG::solenoid=1.0 -o eg12_sol_75k_No_Raster_rec.evio -s DCHB:DCTB:EC:FTOF:EB -config DATA::mc=true -config DCTB::useRaster=true
After the reconstruction a root file was created using
~/src/CLAS/evio2root/bin/evio2root eg12_sol_75k_No_Raster_rec.evio eg12_sol_75k_No_Raster_rec.root 75000
A plot was then created to show the X Vertex and Y Vertex Differences
The first question is why is there a shift in the Y Difference. What would make X more centered around 0? The next question is when rastering begins, why do the resolutions in the X Vertices remain unchanged while the resolutions in the Y Vertices change?
Point in 2-D but extended target in 1-D
Two vertex variables are fixed at zero and the third vertex variable is altered. A 6 GeV electron was fired at angles of 25 degrees in theta and 0 degrees in phi.
| 2cm X Raster, Y=0,Z=0 | 2 cm Y Raster, X=0,Z=0 | 2 cm Z Raster ,X=0,Y=0 | 6 cm Z Raster ,X=0,Y=0 | |
|---|---|---|---|---|
| Vx Difference |  |
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| Vy Difference |  |
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| Vz Difference |  |
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| X Resolution (cm) | 0.2658 +/- 0.0010 | 0.2531 +/- 0.0009 | 0.2544 +/- 0.0009 | 0.2539 +/- 0.0009 |
| Y Resolution(cm) | 0.1728 +/- 0.0007 | 0.2368 +/- 0.0007 | 0.2644 +/- 0.0007 | 0.6191 +/- 0.0013 |
| Z Resolution (cm) | 0.1792 +/- 0.0006 | 0.1998 +/- 0.0004 | 0.4318 +/- 0.0009 | 1.105 +/- 0.002 |
Extended target -3 < Z < 3 cm
| 1cm X Raster | 1 cm Y Raster | 1 cm X & Y Raster | |
|---|---|---|---|
| X Resolution (cm) | 0.2696 +/- 0.0009 | 0.2588 +/- 0.0009 | 0.2734 +/- 0.0009 |
| Y Resolution (cm) | 0.6234 +/- 0.0014 | 0.6851 +/- 0.0014 | 0.6927 +/- 0.0013 |
| Z Resolution (cm) | 1.136 +/- 0.002 | 1.361 +/- 0.002 | 1.381 +/- 0.003 |
| Generated Vx (cm) |  |
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| Generated Vy (cm) |  |
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| Generated Vz (cm) |  |
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| Reconstructed Vx (cm) |  |
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| Reconstructed Vy (cm) |  |
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| Reconstructed Vz (cm) |  |
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| Vx Difference (cm) |  |
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| Vy Difference (cm) |  |
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| Vz Difference (cm) |  |
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Extended target in Z. Vy shift analysis
All Histograms below were created by simply making the target longer along the Z axis. Each case uses vertex points for X and Y ranging from -1cm to 1cm
| 0.5cm Z Target | 1cm Z Target | 2cm Z Target | 3cm Z Target | 4cm Z Target | 5cm Z Target | |
|---|---|---|---|---|---|---|
| X Resolution (cm) | 0.2705 +/- 0.0010 | 0.2726 +/- 0.0010 | 0.2716 +/- 0.0010 | 0.2731 +/- 0.0010 | 0.2702 +/- 0.0009 | 0.2736 +/- 0.0010 |
| Y Resolution (cm) | 0.2041 +/- 0.0010 | 0.2282 +/- 0.0011 | 0.3152 +/- 0.0014 | 0.433 +/- 0.002 | 0.5584 +/- 0.0018 | 0.6454 +/- 0.0015 |
| Z Resolution (cm) | 0.28 +/-0.00 | 0.3582 +/- 0.0013 | 0.5659 +/- 0.0018 | 0.7927 +/- 0.0023 | 1.034 +/- 0.003 | 1.253 +/-0.003 |
| X Mean (cm) | 0.0139 +/- 0.001 | 0.0139 +/- 0.00107 | 0.01436 +/- 0.00104 | 0.01217 +/- 0.00107 | 0.00991 +/- 0.00104 | 0.009022 +/- 0.00105 |
| Y Mean (cm) | -0.1893 +/- 0.0011 | -0.2004 +/- 0.0012 | -0.2379 +/- 0.0016 | -0.2936 +/- 0.0022 | -0.3648 +/- 0.0027 | -0.3871 +/- 0.0026 |
| Z Mean (cm) | 0.0928 +/- 0.0014 | 0.06464 +/- 0.0013 | -0.0337 +/- 0.0028 | -0.1582 +/- 0.0040 | -0.3016 +/- 0.0053 | -0.486 +/- 0.006 |
| Generated Vx (cm) |  |
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| Generated Vy (cm) |  |
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| Generated Vz (cm) |  |
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| Reconstructed Vx (cm) |  |
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| Reconstructed Vy (cm) |  |
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| Reconstructed Vz (cm) |  |
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| Vx Difference (cm) |  |
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| Vy Difference (cm) |  |
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| Vz Difference (cm) |  |
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It would seem that increasing the length of the target in the Z direction has an effect on the resolution of the Y vertex position along with how far the center of the Gaussian peak will shift for the Y vertex differences.
Localized Vertex Resolution Investigation of Line Targets
GEMC was ran to create electrons being produced in a line along certain axes. These include three separate 2cm targets centered at (0,0,0) in the X, Y , and Z directions. The final target is a line along the Z axis centered at (0,0,0) that is 6cm long. The generated electrons were shot at 25 degrees in theta and 0 degrees in phi at an energy of 6GeV.
Here is an example of how the cuts were made. Consider the case of a 2cm line target in the Z direction centered at (0,0,0). Closed intervals begin at the end of the target and are 0.1cm long. So the first interval would be [-1.0,-0.9], then the next would be [-0.9, -0.8] and so on until the entire target is covered. The events in the EVENTHB bank were cut so that in any given interval there would be a margin of +/- 1cm to remove any outliers that may cause the histograms to have long tails.
Below are the histograms for the 2cm line target in Y,X=0,Z=0. The electrons were fired with an energy of 6 GeV at 25 degrees in theta at 0 degrees in phi.
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
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| Interval | Resolution (cm) | Vy Difference | *** | Interval | Resolution (cm) | Vy Difference |
| [-1.0,-0.9] | 0.09406 +/- 0.00128 |  |
*** | [0.9,1.0] | 0.1001 +/- 0.0016 | 
|
| [-0.9,-0.8] | 0.0868 +/- 0.0013 |  |
*** | [0.8,0.9] | 0.1221 +/- 0.0018 | 
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| [-0.8,-0.7] | 0.08961 +/- 0.00128 |  |
*** | [0.7,0.8] | 0.1144 +/- 0.0017 | 
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| [-0.7,-0.6] | 0.09853 +/- 0.00148 |  |
*** | [0.6,0.7] | 0.169 +/- 0.003 | 
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| [-0.6,-0.5] | 0.1038 +/- 0.0016 |  |
*** | [0.5,0.6] | 0.171 +/- 0.003 | 
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| [-0.5,-0.4] | 0.1202 +/- 0.0018 |  |
*** | [0.4,0.5] | 0.1105 +/- 0.0016 | 
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| [-0.4,-0.3] | 0.1755 +/- 0.0026 |  |
*** | [0.3,0.4] | 0.09508 +/- 0.00137 | 
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| [-0.3,-0.2] | 0.1847 +/- 0.0028 |  |
*** | [0.2,0.3] | 0.09065 +/- 0.0140 | 
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| [-0.2,-0.1] | 0.1255 +/- 0.0019 |  |
*** | [0.1,0.2] | 0.093002 +/- 0.0013 | 
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| [-0.1,0.0] | 0.09663 +/- 0.00160 |  |
*** | [0.0,0.1] | 0.09008 +/- 0.0012 | 
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Below are the histograms for a 2cm target along the Y axis, X = 0 Z = 0. The electrons were fired with an energy of 6 GeV at 25 degrees in theta and 180 degrees in phi.
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
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| Interval | Resolution (cm) | Vy Difference | *** | Interval | Resolution (cm) | Vy Difference |
| [-1.0,-0.9] | 0.07741 +/- 0.00166 |  |
*** | [0.9,1.0] | 0.2319 +/- 0.0189 | 
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| [-0.9,-0.8] | 0.0976 +/- 0.0017 |  |
*** | [0.8,0.9] | 0.2147 +/- 0.0185 | 
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| [-0.8,-0.7] | 0.09924 +/- 0.00150 |  |
*** | [0.7,0.8] | 0.2364 +/- 0.0188 | 
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| [-0.7,-0.6] | 0.1386 +/- 0.0024 |  |
*** | [0.6,0.7] | 0.2323 +/- 0.0189 | 
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| [-0.6,-0.5] | 0.1278 +/- 0.0027 |  |
*** | [0.5,0.6] | 0.06016 +/- 0.00299 | 
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| [-0.5,-0.4] | 0.09882 +/- 0.00142 |  |
*** | [0.4,0.5] | 0.3986 +/- 0.00104 | 
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| [-0.4,-0.3] | 0.09322 +/- 0.0013 |  |
*** | [0.3,0.4] | 0.3056 +/- 0.0047 | 
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| [-0.3,-0.2] | 0.09399 +/- 0.00145 |  |
*** | [0.2,0.3] | 0.1097 +/- 0.0029 | 
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| [-0.2,-0.1] | 0.08935 +/- 0.00131 |  |
*** | [0.1,0.2] | 0.1146 +/- 0.0025 | 
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| [-0.1,0.0] | 0.08913 +/- 0.00130 |  |
*** | [0.0,0.1] | 0.09557 +/- 0.0015 | 
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Below are the Histograms for a 2cm long target in the X Direction with a 6GeV electron fired at 25 degrees in theta and 90 degrees in phi
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
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| Interval | Resolution (cm) | Vx Difference | *** | Interval | Resolution (cm) | Vx Difference |
| [-1.0,-0.9] | 0.1341 +/- 0.0140 |  |
*** | [0.9,1.0] | 0.01572 +/- 0.0002 | 
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| [-0.9,-0.8] | 0.1304 +/- 0.0051 |  |
*** | [0.8,0.9] | 0.01844 +/- 0.00031 | 
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| [-0.8,-0.7] | 0.1182 +/- 0.0036 |  |
*** | [0.7,0.8] | 0.01722 +/- 0.0028 | 
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| [-0.7,-0.6] | 0.09062 +/- 0.0031 |  |
*** | [0.6,0.7] | 0.02386 +/- 0.00088 | 
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| [-0.6,-0.5] | 0.06816 +/- 0.00191 |  |
*** | [0.5,0.6] | 0.024 +/- 0.001 | 
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| [-0.5,-0.4] | n/a |  |
*** | [0.4,0.5] | 0.04406 +/- 0.00182 | 
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| [-0.4,-0.3] | 0.0635 +/- 0.0013 |  |
*** | [0.3,0.4] | 0.04517 +/- 0.00118 | 
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| [-0.3,-0.2] | 0.0618 +/- 0.0012 |  |
*** | [0.2,0.3] | 0.04722 +/- 0.00107 | 
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| [-0.2,-0.1] | 0.07473 +/- 0.00178 |  |
*** | [0.1,0.2] | 0.05667 +/- 0.00106 | 
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| [-0.1,0.0] | 0.08787 +/- 0.00132 |  |
*** | [0.0,0.1] | 0.08356 +/- 0.00159 | 
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Below are the Vx Differences using a 2cm target in X with incident 6 GeV electrons at 25 degrees in theta and 270 degrees in phi
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
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| Interval | Resolution (cm) | Vx Difference | *** | Interval | Resolution (cm) | Vx Difference |
| [-1.0,-0.9] | 0.01571 +/- 0.0002 |  |
*** | [0.9,1.0] | 0.1257 +/- 0.0100 | 
|
| [-0.9,-0.8] | 0.0163 +/- 0.0003 |  |
*** | [0.8,0.9] | 0.112 +/- 0.004 | 
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| [-0.8,-0.7] | 0.01821 +/- 0.0003 |  |
*** | [0.7,0.8] | 0.1162 +/- 0.0034 | 
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| [-0.7,-0.6] | 0.03065 +/- .000163 |  |
*** | [0.6,0.7] | 0.08958 +/- 0.00316 | 
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| [-0.6,-0.5] | 0.02109 +/- 0.00217 |  |
*** | [0.5,0.6] | 0.07347 +/- 0.00210 | 
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| [-0.5,-0.4] | 0.03772 +/- 0.00133 |  |
*** | [0.4,0.5] | 0.07271 +/- 0.00159 | 
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| [-0.4,-0.3] | 0.04817 +/- 0.00125 |  |
*** | [0.3,0.4] | 0.06196 +/- 0.00146 | 
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| [-0.3,-0.2] | 0.05154 +/- 0.00113 |  |
*** | [0.2,0.3] | 0.06087 +/- 0.00114 | 
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| [-0.2,-0.1] | 0.05677 +/- 0.00106 |  |
*** | [0.1,0.2] | 0.07298 +/- 0.00149 | 
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| [-0.1,0.0] | 0.08348 +/- 0.00144 |  |
*** | [0.0,0.1] | 0.09017 +/- 0.00128 | 
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Below are the histograms for a 6cm target in the Z direction using a 6 GeV electron fired at 25 degrees in theta and 0 degrees in phi.
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
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| Interval | Resolution (cm) | Vz Difference | *** | Interval | Resolution (cm) | Vz Difference |
| [-3.0,-2.5] | 0.1427 +/- 0.0009 |  |
*** | [2.5,3.0] | 0.1467 +/- 0.0008 | 
|
| [-2.5,-2.0] | 0.1412 +/- 0.0008 |  |
*** | [2.0,2.5] | 0.1419 +/- 0.0009 | 
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| [-2.0,-1.5] | 0.1365 +/- 0.0007 |  |
*** | [1.5,2.0] | 0.1372 +/- 0.0008 | 
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| [-1.5,-1.0] | 0.1439 +/- 0.0008 |  |
*** | [1.0,1.5] | 0.1394 +/- 0.0008 | 
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| [-1.0,-0.5] | 0.1429 +/- 0.0008 |  |
*** | [0.5,1.0] | 0.1584 +/- 0.0010 | 
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| [-0.5,0.0] | 0.1332 +/- 0.0007 |  |
*** | [0.0,0.5] | 0.1378 +/- 0.0009 | 
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Below are the histograms for a 6cm target in the Z direction using a 6 GeV electron fired at 25 degrees in theta and 90 degrees in phi.
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
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| Interval | Resolution (cm) | Vz Difference | *** | Interval | Resolution (cm) | Vz Difference |
| [-3.0,-2.5] | 0.1192 +/- 0.0005 |  |
*** | [2.5,3.0] | 0.1211 +/- 0.0005 | 
|
| [-2.5,-2.0] | 0.1205 +/- 0.0005 |  |
*** | [2.0,2.5] | 0.1251 +/- 0.0005 | 
|
| [-2.0,-1.5] | 0.122 +/- 0.001 |  |
*** | [1.5,2.0] | 0.1312 +/- 0.0006 | 
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| [-1.5,-1.0] | 0.1249 +/- 0.0006 |  |
*** | [1.0,1.5] | 0.1233 +/- 0.0005 | 
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| [-1.0,-0.5] | 0.1278 +/- 0.0006 |  |
*** | [0.5,1.0] | 0.1254 +/- 0.0005 | 
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| [-0.5,0.0] | 0.1289 +/- 0.0006 |  |
*** | [0.0,0.5] | 0.1237 +/- 0.0005 | 
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Below are the histograms for a 6 GeV electron fired at angles 25 degrees in theta and 270 degrees in phi. The target was 6cm in the Z direction.
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
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| Interval | Resolution (cm) | Vz Difference | *** | Interval | Resolution (cm) | Vz Difference |
| [-3.0,-2.5] | 0.1171 +/- 0.0008 |  |
*** | [2.5,3.0] | 0.1186 +/- 0.0008 | 
|
| [-2.5,-2.0] | 0.1162 +/- 0.0008 |  |
*** | [2.0,2.5] | 0.1226 +/- 0.0009 | 
|
| [-2.0,-1.5] | 0.1207 +/- 0.0009 |  |
*** | [1.5,2.0] | 0.1317 +/- 0.0010 | 
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| [-1.5,-1.0] | 0.1294 +/- 0.0010 |  |
*** | [1.0,1.5] | 0.1239 +/- 0.0009 | 
|
| [-1.0,-0.5] | 0.131 +/- 0.001 |  |
*** | [0.5,1.0] | 0.1256 +/- 0.0009 | 
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| [-0.5,0.0] | 0.131 +/- 0.001 |  |
*** | [0.0,0.5] | 0.1261 +/- 0.0010 | 
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Below are the histograms for a 6 GeV electron fired at 25 degrees in theta and 0 degrees in phi. The target is 2cm long on the Y axis.
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
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| Interval | Resolution (cm) | Vy Difference | *** | Interval | Resolution (cm) | Vy Difference |
| [-1.0,-0.9] | 0.09406 +/- 0.00128 | |
*** | [0.9,1.0] | 0.1001 +/- 0.0016 |
|
| [-0.9,-0.8] | 0.0868 +/- 0.0013 | |
*** | [0.8,0.9] | 0.1221 +/- 0.0018 |
|
| [-0.8,-0.7] | 0.08961 +/- 0.00128 | |
*** | [0.7,0.8] | 0.1144 +/- 0.0017 |
|
| [-0.7,-0.6] | 0.09853 +/- 0.00148 | |
*** | [0.6,0.7] | 0.169 +/- 0.003 |
|
| [-0.6,-0.5] | 0.1038 +/- 0.0016 | |
*** | [0.5,0.6] | 0.171 +/- 0.003 |
|
| [-0.5,-0.4] | 0.1202 +/- 0.0018 | |
*** | [0.4,0.5] | 0.1105 +/- 0.0016 |
|
| [-0.4,-0.3] | 0.1755 +/- 0.0026 | |
*** | [0.3,0.4] | 0.09508 +/- 0.00137 |
|
| [-0.3,-0.2] | 0.1847 +/- 0.0028 | |
*** | [0.2,0.3] | 0.09065 +/- 0.0140 |
|
| [-0.2,-0.1] | 0.1255 +/- 0.0019 | |
*** | [0.1,0.2] | 0.093002 +/- 0.0013 |
|
| [-0.1,0.0] | 0.09663 +/- 0.00160 | |
*** | [0.0,0.1] | 0.09008 +/- 0.0012 |
|
Below are the histograms for a 2cm target along the Y axis, X = 0 Z = 0. The electrons were fired with an energy of 6 GeV at 25 degrees in theta and 30 degrees in phi.
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
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| Interval | Resolution (cm) | Vy Difference | *** | Interval | Resolution (cm) | Vy Difference |
| [-1.0,-0.9] | 0.069 +/- 0.002 |  |
*** | [0.9,1.0] | 0.04936 +/- 0.00068 | 
|
| [-0.9,-0.8] | 0.08185 +/- 0.00218 |  |
*** | [0.8,0.9] | 0.05797 +/- 0.00094 | 
|
| [-0.8,-0.7] | 0.08764 +/- 0.00212 |  |
*** | [0.7,0.8] | 0.05896 +/- 0.00086 | 
|
| [-0.7,-0.6] | 0.09158 +/- 0.00258 |  |
*** | [0.6,0.7] | 0.05895 +/- 0.00091 | 
|
| [-0.6,-0.5] | 0.07913 +/- 0.00166 |  |
*** | [0.5,0.6] | 0.05943 +/- 0.00096 | 
|
| [-0.5,-0.4] | 0.0774 +/- 0.0014 |  |
*** | [0.4,0.5] | 0.06227 +/- 0.00118 | 
|
| [-0.4,-0.3] | 0.07978 +/- 0.00157 |  |
*** | [0.3,0.4] | 0.08115 +/- 0.00186 | 
|
| [-0.3,-0.2] | 0.08193 +/- 0.00235 |  |
*** | [0.2,0.3] | 0.01028 +/- 0.0029 | 
|
| [-0.2,-0.1] | 0.1812 +/- 0.0025 |  |
*** | [0.1,0.2] | 0.136 +/- 0.003 | 
|
| [-0.1,0.0] | 0.1503 +/- 0.0021 |  |
*** | [0.0,0.1] | 0.2052 +/- 0.0033 | 
|
Below are the histograms for a 2cm Y target with an incident electron energy of 6 GeV. The angles were theta = 25 degrees and phi = 210 degrees
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
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| Interval | Resolution (cm) | Vy Difference | *** | Interval | Resolution (cm) | Vy Difference |
| [-1.0,-0.9] | 0.04815 +/- 0.00067 |  |
*** | [0.9,1.0] | 0.07184 +/- 0.00181 | 
|
| [-0.9,-0.8] | 0.05734 +/- 0.00091 |  |
*** | [0.8,0.9] | 0.08837 +/- 0.00268 | 
|
| [-0.8,-0.7] | 0.05873 +/- 0.00085 |  |
*** | [0.7,0.8] | 0.0982 +/- 0.0024 | 
|
| [-0.7,-0.6] | 0.05868 +/- 0.00089 |  |
*** | [0.6,0.7] | 0.09622 +/- 0.00305 | 
|
| [-0.6,-0.5] | 0.05962 +/- 0.00098 |  |
*** | [0.5,0.6] | 0.08028 +/- 0.00156 | 
|
| [-0.5,-0.4] | 0.0645 +/- 0.0014 |  |
*** | [0.4,0.5] | 0.07917 +/- 0.00163 | 
|
| [-0.4,-0.3] | 0.0861 +/- 0.0020 |  |
*** | [0.3,0.4] | 0.08056 +/- 0.00159 | 
|
| [-0.3,-0.2] | 0.1003 +/- 0.0024 |  |
*** | [0.2,0.3] | 0.08939 +/- 0.00201 | 
|
| [-0.2,-0.1] | 0.1305 +/- 0.0024 |  |
*** | [0.1,0.2] | 0.186 +/- 0.003 | 
|
| [-0.1,0.0] | 0.2042 +/- 0.0033 |  |
*** | [0.0,0.1] | 0.1476 +/- 0.0021 | 
|
Localized Vertex Resolution Investigation of 2 Dimensional Targets
The histograms below were created using a 6 GeV electron fired at 25 degrees in theta and 30 degrees in phi. To make the cuts I simply made circles of increasing radius centered at the origin. I used 0.1cm increments to make the 10 histograms for each vertex position.
Below are the Vx and Vy Differences for a 2cm XY target, Z=0.
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
 |
 |
 |
 |
 |
|
| Radius (cm) | Resolution (cm) | Vx Difference | *** | Radius (cm) | Resolution (cm) | Vx Difference |
| 0.1 | 0.2309 +/- 0.0091 |  |
*** | 0.6 | 0.259 +/- 0.001 | 
|
| 0.2 | 0.235 +/- 0.004 |  |
*** | 0.7 | 0.2769 +/- 0.0014 | 
|
| 0.3 | 0.2242 +/- 0.0028 |  |
*** | 0.8 | 0.2927 +/- 0.0013 | 
|
| 0.4 | 0.2272 +/- 0.0020 |  |
*** | 0.9 | 0.3074 +/- 0.0013 | 
|
| 0.5 | 0.2422 +/- 0.0016 |  |
*** | 1.0 | 0.3237 +/- 0.0014 | 
|
| Radius (cm) | Resolution (cm) | VyDifference | *** | Radius (cm) | Resolution (cm) | Vy Difference |
| 0.1 | 0.162 +/- 0.006 |  |
*** | 0.6 | 0.1733 +/- 0.0020 | 
|
| 0.2 | 0.1798 +/- 0.0031 |  |
*** | 0.7 | 0.1661 +/- 0.0017 | 
|
| 0.3 | 0.1947 +/- 0.0028 |  |
*** | 0.8 | 0.1615 +/- 0.0015 | 
|
| 0.4 | 0.1959 +/- 0.0033 |  |
*** | 0.9 | 0.1578 +/- 0.0013 | 
|
| 0.5 | 0.1861 +/- 0.0027 |  |
*** | 1.0 | 0.4832 +/- 0.0035 | 
|
Below are the Vy and Vz differences for a 2cm target in Y and Z, X=0. The electrons were fired with an energy of 6 GeV and angles of 25 degrees in theta and 30 degrees in phi.
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
 |
 |
 |
 |
 |
|
| Radius (cm) | Resolution (cm) | Vy Difference | *** | Radius (cm) | Resolution (cm) | Vy Difference |
| 0.1 | 0.1722 +/- 0.0065 |  |
*** | 0.6 | 0.1806 +/- 0.0017 | 
|
| 0.2 | 0.1773 +/- 0.0037 |  |
*** | 0.7 | 0.1868 +/- 0.0015 | 
|
| 0.3 | 0.1781 +/- 0.0031 |  |
*** | 0.8 | 0.1974 +/- 0.0014 | 
|
| 0.4 | 0.1734 +/- 0.0024 |  |
*** | 0.9 | 0.2028 +/- 0.0013 | 
|
| 0.5 | 0.1764 +/- 0.0020 |  |
*** | 1.0 | 0.221 +/- 0.001 | 
|
| Radius (cm) | Resolution (cm) | Vz Difference | *** | Radius (cm) | Resolution (cm) | Vz Difference |
| 0.1 | 0.07095 +/- 0.00239 |  |
*** | 0.6 | 0.261 +/- 0.001 | 
|
| 0.2 | 0.1063 +/- 0.0015 |  |
*** | 0.7 | 0.2874 +/- 0.0010 | 
|
| 0.3 | 0.146 +/- 0.001 |  |
*** | 0.8 | 0.3232 +/- 0.0011 | 
|
| 0.4 | 0.1833 +/- 0.0012 |  |
*** | 0.9 | 0.3528 +/- 0.0010 | 
|
| 0.5 | 0.2222 +/- 0.0012 |  |
*** | 1.0 | 0.3847 +/- 0.0010 | 
|
Below are the Vx and Vz differences for a 2cm XZ target, Y = 0. The electrons were fired with an energy of 6 GeV at angles theta = 25 degrees and phi = 30 degrees.
| GenPart.x | GenPart.y | GenPart.z | Event.x | Event.y | Event.z |
 |
 |
 |
 |
 |
|
| Radius (cm) | Resolution (cm) | Vz Difference | *** | Radius (cm) | Resolution (cm) | Vz Difference |
| 0.1 | 0.06193 +/- 0.00199 |  |
*** | 0.6 | 0.2495 +/- 0.0012 | 
|
| 0.2 | 0.1059 +/- 0.0015 |  |
*** | 0.7 | 0.2862 +/- 0.0011 | 
|
| 0.3 | 0.1412 +/- 0.0013 |  |
*** | 0.8 | 0.3172 +/- 0.001 | 
|
| 0.4 | 0.1704 +/- 0.0012 |  |
*** | 0.9 | 0.3512 +/- 0.0012 | 
|
| 0.5 | 0.2183 +/- 0.0013 |  |
*** | 1.0 | 0.4066 +/- 0.0013 | 
|
| Radius (cm) | Resolution (cm) | Vx Difference | *** | Radius (cm) | Resolution (cm) | Vx Difference |
| 0.1 | 0.2125 +/- 0.0090 |  |
*** | 0.6 | 0.2365 +/- 0.0016 | 
|
| 0.2 | 0.2392 +/- 0.0044 |  |
*** | 0.7 | 0.2307 +/- 0.0013 | 
|
| 0.3 | 0.251 +/- 0.003 |  |
*** | 0.8 | 0.2251 +/- 0.0012 | 
|
| 0.4 | 0.2494 +/- 0.0023 |  |
*** | 0.9 | 0.222 +/- 0.001 | 
|
| 0.5 | 0.2439 +/- 0.0019 |  |
*** | 1.0 | 0.2193 +/- 0.0010 | 
|
Localized Vertex Resolution of 3 Dimensional targets
For the plots below, a 6 GeV electron was fired at angles 25 degrees in theta and 30 degrees in phi. The target has an XY radius of 1cm and a length in the Z direction of 6cm. Setting GenPart.z = 0cm, the resolution was investigated as a function of the target's XY radius along with a table for the values.
clas12->Draw("Event.z >> (100,-5,5)","sqrt(GenPart.x*GenPart.x+GenPart.y*GenPart.y)<0.95 && sqrt(GenPart.x*GenPart.x+GenPart.y*GenPart.y)>0.85");
| R (cm) | 0.05 +/- 0.05 | 0.15 +/- 0.05 | 0.25 +/- 0.05 | 0.35 +/- 0.05 | 0.45 +/- 0.05 | 0.55 +/- 0.05 | 0.65 +/- 0.05 | 0.75 +/- 0.05 | 0.85 +/- 0.05 | 0.95 +/- 0.05 |
| Width (cm) | 0.05094 +/- 0.0019 | 0.07812 +/- 0.0018 | 0.3688 +/- 0.0063 | 0.5231 +/- 0.0077 | 0.718 +/- 0.012 | 0.7987 +/- 0.0092 | 0.8709 +/- 0.0085 | 1.038 +/- 0.01 | 1.183 +/- 0.012 | 1.296 +/- 0.013 |
For this section I created a target that is 2cm in X and Y, and 6cm in Z. To produce the histograms I made a cut in the radius of a cylinder (R=0.1cm, R=0.2cm, .... , R=1.0cm) and also cut Z (Z=1cm, Z=2cm,...,Z=6cm) so that for each fixed radius there will be 6 histograms corresponding to changes in Z. For example, assume I am using R=0.1cm. There will be 6 histograms for X,Y,and Z corresponding to changing Z from 1cm to 6cm in 1cm increments. I also placed a cut for the reconstructed events using the commands abs(Event.z) <= 4.0 and sqrt(Event.x*Event.x+Event.y*Event.y) <=1.
For the plots below, a 6 GeV electron was fired at angles 25 degrees in theta and 30 degrees in phi. The target has an XY radius of 1cm and a length in the Z direction of 6cm. Setting GenPart.z = 0cm, the resolution was investigated as a function of the target's XY radius along with a table for the values.
Below are the Vx Differences for R=1.0cm as an example.
| Z (cm) | Resolution (cm) | Vx Difference | *** | Z (cm) | Resolution (cm) | Vx Difference |
| 1.0 | 0.305 +/- 0.003 |  |
*** | 4.0 | 0.3459 +/- 0.0018 | 
|
| 2.0 | 0.307 +/- 0.003 |  |
*** | 5.0 | 0.3688 +/- 0.0016 | 
|
| 3.0 | 0.3214 +/- 0.0021 |  |
*** | 6.0 | 0.3877 +/- 0.0015 | 
|
Elastic electron proton GEMC 2.4 & Coatjava 2.4
References
https://clasweb.jlab.org/wiki/index.php/TF_EG12_Vertex#Z_resolution_With_micro-megas