BigBite Optics et cetera #16
Optics Calibration
I have considered Doug's advice and applied additional cut to
my analysis. I have demanded that the difference between BigBite-TgY
and HRSL-ReactZ*sin(phi) must be smaller than 0.017m:
|BB.gold.y - ReactPy_L.z*sin(phi)| < 0.017m
1.7cm is a typical width of our TgY peaks. This new cut has
significantly cleaned my "golden" data set and gives me very nice results.
Now I can clearly see holes in the bottom of the sieve, that were not
visible before. From the results below we can see, that not all 6 (7) holes
are visible but only 3(4) in the middle:
Once I clearly see my holes, I included them into my fitting algorithm and
tried to reconstruct the whole sieve pattern. I have not fit the whole sieve
at once, but systematically added points to the sieve - fitting algorithm. First
I determined the TgPh matrix elements only for the holes in the bottom of the sieve. Then in every next step of my fitting procedure I added more and more holes, moving slowely to the top of the sieve. Figures below show this sequence.
In the end I realized, that my fitting algorithm works well with all the holes except with those on the top of the sieve (low momentum side). I have discovered, that I have the same problem with these holes as I had with the
ones in the bottom. I have not assigned the correct holes in the focal-plane to
the correct sieve holes. Figure below shows new and old cuts that I have used to assign events in the FP to the correct hole in the sieve:
When I fix this problem I believe that I will be able to see clearly the complete sieve pattern.
Current Results:
Here are my current best results for the sieve-pattern reconstruction, etc. In these plots I consider only Carbon runs #3489, #3490 and #3491, while in the plots above I also included Hydrogen run #3488 and runs #3493 and #3495:
Last modified: 07/21/10
