Meeting No.12: BigBite Optics Calibration #5

Current BigBite Optics Matrix:

[matrix]
t 1 0 0  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
y 1 0 0  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
p 1 0 0  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00

D 0 0 0  -0.0062343  -0.9545440  1.13910000  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
D 1 0 0  3.39098000  -7.6819500  7.76604000  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
D 2 0 0  11.7304000  -19.230500  21.1691000  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
D 3 0 0  14.3041000  -8.6769400  3.53875000  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00

T 0 0 0  0.01067500  -0.4968080  -0.1145100  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
T 1 0 0  0.49109200  0.12139600  -0.4243960  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00

P 0 0 1  1.00000000  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00

Y 0 0 0  -0.0321556  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
Y 0 1 0  -1.0241000  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
Y 0 2 0  -0.4919260  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
Y 0 0 1  2.80775000  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
Y 0 1 1  0.72023300  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
Y 0 2 1  -0.7153320  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00

TgY matrix elements determination:

I have tried to use the same method, that I have been using for TgDelta, also for the determination of the TgY matrix elements. It turned out that this method was not working well, because of to much noise on the plots. Therefore I had do develop a different method. Since I was using carbon runs with sieve In for the calibration of TgY matrix elements, I decided to use the folowing method. First I determimed the mean positions of the carbon peaks and their widths. Once I knew these values I made cuts around each peak and checked the mean position of the FpPh variable at many different values of FpY. I have used Gaussian function to determine the mean value of FpPh for each setting of FpY and TgY. I have changed the values of FpY from -0.15 to 0.15 in steps of 0.015. This way I was able to determine how TgY depends on FpY and FpPh. Please see the figure below:

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Results for 2nd Pass Hydrogen Run #3488:

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Results for 1st Pass Hydrogen Run #1518:

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Results for 2nd Pass Carbon Run #3491:

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Results for 2nd Pass Carbon Run #3491 (No ReactZ cut):

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Results for 2nd Pass Carbon Run #3491 (No ReactZ cut & BB.tr.p >0.45):

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Results for 2nd Pass Carbon Run #3491 (No ReactZ cut & BB.tr.p >0.55):

Here we can see how Focal plane plots (FpY vs. FpPh ) are much cleaner (less noise), when we introduce a cut on the BB momentum. We suspect that the noise that we observe is caused by the protons that manage to punch through the material of the collimator. The thickness of the collimator is 1.5inc = 3.75 cm, while the range of the 500MeV/c protons is approximately 4cm.

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