1. d.forrest@physics.gla.ac.uk 21 October 2008 (CM22)
Misalignment Study
David Forrest
University of Glasgow
21 October 2008 (CM22)
If you would like to use the grid tell me I would be happy to give you copious help in getting sorted out on it

2. Introduction to the study
- Misalignment of the downstream spectrometer only (Step VI of MICE)
- Translational and rotational misalignments studied
- 10 mm, 3mrad and both combined. For x and y.
- Independent MC simulations (G4MICE, Grid, Ganga)
- 10,000 events

3. Cuts Cutting on single particle emittance
Emittance 4D=mean(amplitude4D)/4
Cutting out muons that don’t make it to the second tracker – ~85% transmission (this is very very fresh, transmission graphs to follow at analysis meeting, mice note)

4. Baseline - bump. Explanations? Spline, cuts applied 4 up.
No longer seeing muon collider type cooling now is of order 10 percent for a ten pi beam

5. 3 mrad X
3mrad Rotational Misalignment (X)

6. 3mrad rotation (Y)
3 mrad Rotation (Y)

7. Both in X
Translational and Rotational (X)

8. Both in Y
Translational and Rotational (Y)

9. What about statistics?
- We calculate 4D emittance by taking the fourth root of a determinant of a matrix of covariances
- What's the error on that?
- Assume proportional to sqrt(1/N)...
- What is the factor of proportionality?

10. Means
500 1k event runs
50 10k event runs

11. 99% of statistics are made up

12. Stats conclusions
- This is just a short attempt at probing the constant of proportionality, using the grid.
- that constant is thankfully not 1, but it is not 0.1 either (proving jhc right when he said he was wrong), both of which are good to know.
- I want to try and develop this
- It's difficult to make statements about the effect of misalignment without an understanding of the affect of statistics

13. Misalignment conclusions
Assume that effect scales linearly
effect between 1-5%
Higher than before. Previously predicted 3 mm, 1mrad alignment constraints. New ones will be stricter, perhaps 1mm, 0.3 mrad. Next analysis phone meeting and mice note will be more precise
Misalignment conclusions

14. Future work
- I should probably simulate that precise misalignment to confirm linear assumption
- But I really want to try and separate the influence of statistics before doing much else
- Finalise table and thump out a MICE note (+ one on GRID. Already written but volatile to change)
- Digitisation, Reconstruction etc remains to be done