Meeting No.10: BigBite Optics Calibration #3

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  -0.0292416  -0.9033330  1.81944000  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
D 1 0 0  3.43311000  -9.7937800  11.4550000  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
D 2 0 0  15.5068000  -50.202100  -23.181100  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
D 3 0 0  26.7883000  -66.026900  0.00000000  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  0.03528600  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
Y 0 1 0  0.99801300  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
Y 0 0 1  -2.8008400  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00
Y 0 1 1  -0.6388680  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00   0.0000E+00

DB_run.dat Problem

I believe that BigBite information in the DB_run.dat file are not correct. BigBite scattering angle is set to -74deg, although bigbite was positioned at -74deg during Ay and -75deg during e'd. The central momentum of the BigBite also needs to be set. At the moment I set it to 0.5GeV/c which approximately corresponds to the correct setting according to NIKHEF BigBite paper. At 518A the field inside the BigBite is 0.92T and the central momentum is 0.5GeV/c

Scattering angle issue

Halog states that for runs at the beginning of our run period (e.g. #1518) BigBite was positioned at 71deg. This is right in the middle of the elastic peak. However, when I compare the "BB.tr.ph" variable with the phi angle of the "q"-vector rotated into the BB-coordinate system, thing do not match if I consider 71deg as a central scattering angle. Things get much more consistant, when I assume, that BB was positioned at 74deg. Please see figures below. This suggests that BB was never at 71deg.

BigBite Collimator

BigBite Collimator Technical Drawing: BBCollimator.pdf

BigBite collimator reconstruction using current BB optics matrix:

"BB.tr.x" vs. "BB.tr.th" plots:

Plot without any cuts:

1st Reconstruction Model:

This plots shows which regions in focal plane correspond to different momenta. In this model I used second order polynomials in both theta and x to reconstruct delta.

2nd Reconstruction Model:

This plots shows which regions in focal plane correspond to different momenta. In this model I used second order polynomials in theta and linear functions in x to reconstruct delta.

3rd Reconstruction Model:

This plots shows which regions in focal plane correspond to different momenta. In this model I used third order polynomials in theta and second order polynomials in x to reconstruct delta.

Tg_dp calibration:

I want to include deuterium elastic runs into my optics matrix calibration. In order to do so, I need to isolate elastic deuterons from elastic protons. I am trying to do this by applying different cuts on dE/E plots. Here are the results of this procedure for different runs:

Details on the dE/E cut determination are here (Mathematica): EdEManipulation.pdf

Details on the delta matrix element determination are here (Mathematica): fit5.pdf