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resolution_downstream_triplet1=std(difftriplet1)/(sqrt(3/2));

Definition of resolution and misalignment:.

walter-trevino
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resolution_downstream_triplet1=std(difftriplet1)/(sqrt(3/2));

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  1. Definition of resolution and misalignment: For the triplets the resolution is the error in the “difftriplet” which is the difference between a “predicted” value given by a linear fit of the most externals BPMs and the actual value of the middle BPM. The misalignment is the average of these differences. For the doublets the resolution is the error of the difference in their respective measurements. The misalignment is the average of these differences. resolution_downstream_triplet1=std(difftriplet1)/(sqrt(3/2)); misalignment_triplet1=mean(difftriplet1); resolution_downstream_triplet2=std(difftriplet2)/(sqrt(3/2)); misalignment_triplet2=mean(difftriplet2); resolution31_32=std(bpmupstreamdiff12)/(sqrt(2)); misalignment31_32=mean(bpmupstreamdiff12); resolution41_42=std(bpmupstreamdiff34)/(sqrt(2)); misalignment41_42=mean(bpmupstreamdiff34); The next table gives the resolutions and misalignments for several runs in sandwich 1.

  2. It would seem that the resolution (and misalignment) of the second triplet is affected when slot 3 is on. Is the big kick reconstructed at collimator position 1 mm related to this? The next slides show the plots of reconstructed kick vs collimator position for slot 3 and resolution plot for of the second triplet for this same run.

  3. Run 595 in s1s3

  4. Run 619 in s1s3

  5. Run 638 in s1s3

  6. Run 657 in s1s3

  7. Which we can compare with some runs made at the other slots: Run 585 in s1s1

  8. Run 588 in s1s2 Run 599 in s1s4

  9. The next slides show a comparison between the reconstructed kick when using or dumping BPM9. Also the average misalignment and resolution per collimator position for the first and second triplet. In the case of the second triplet a comparison when using the whole triplet (BPM9, BPM10, BPM11) or when dumping BPM9.

  10. 595 Without BPM9

  11. 619 Without BPM9

  12. 638 Without BPM9

  13. 657 Without BPM9

  14. The second peak in the distribution of misalignments for the second triplet it is mainly due to the collimator positions 1 mm and in a minor part to the position of 0.8 mm. When the collimator is in these positions affects the misalignment (and resolution) of both downstream triplets. When in these positions BPM9 seems to be very affected having a huge impact in misalignment and resolution. When this BPM is removed from the calculation of misalignment and resolution the resolutions are improved (there is still misalignment) but the kick reconstruction is barely affected. Even if the second peak in the misalignment distribution is more important at position 1 mm than at position 0.8 mm I would expect a bigger kick as well for that position, similar to the position 1 mm, which is not there. I do not know what is going on with the resolution at position 0.6 mm (which doesn’t show any important misalignment). The same observations are made for all the runs of sandwich 1 slot 3.

  15. Could these big kick effect, and misalignment effect seen downstream be due to some shower of particles coming from the bunch halo scrapping the collimator at positions 0.8 and 1 mm? Even after removing BPM9 the misalignment is still important (not the resolution) and the big (irreal?) kick is still there. The same effects are also seen in the first triplet. I believe it is fair to remove the reconstructed kick at position 1mm.

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