1. Early Results from Beam Line Studies Jean-Sebastien Graulich, Geneva
Aim
Proton/Pion beam content
Magnet Alignment
CM22 October 2008
Jean-Sebastien Graulich

2. Jean-Sebastien Graulich
Aim
Disclaimer
I am not a beam line expert
Analysis not complete
The aims (as far as I understand)
Get knowledge of the beam content
Assert Magnet Alignment
Start training on Experiment/Simulation comparison
CM22 October 2008
Jean-Sebastien Graulich

3. Will be presented by Vassil Verguilov in the next talk
Overview
Three measurement campaigns
July 13-14: Momentum and B2 scan.
Main topic: Proton/Pion beam content
Detectors: GVA1/GVA2
July 18-20: Quad scan.
Main topic: Magnet Alignment
Detectors: TOF0 in temporary position (before Q7)
Sept 12-13: Momentum scan. Pion/Positron beam content
Main Topics: Demonstrate e+ beam, CKOV response
Detectors: TOF0 in nominal position, CKOV, GVA1/2
Will be presented by Vassil Verguilov in the next talk
CM22 October 2008
Jean-Sebastien Graulich

4. Proton/Pion beam content
Results already presented by Dazhang Huang in VC 113
Also in Mice Note 211
CKOV A,B
Dipole 1
Dipole 2
CM22 October 2008
Jean-Sebastien Graulich

5. Jean-Sébastien Graulich
Method
Q4, Q5, Q6 OFF
Start with 480 MeV/c proton momentum at B1.
Tune Q1, Q2 and Q3 maximize rate in GVA2
Scan dipole magnet B2 at various proton momentums : 414 MeV/c, 374 MeV/c, 322 MeV/c, and measure Pion and Proton productions
Pion/Proton separation by TOF between GVA1 and GVA2
Pion and Proton productions are normalised to the total number of counts at GVA1
Field/Current
Not linear !
Pion
Proton
CM 22 October 2008
Jean-Sébastien Graulich

6. D. Huang, MICE video conference
Rates
The number is decreasing as lowering the proton momentum.
Seems consistent with expectation
D. Huang, MICE video conference

7. Jean-Sébastien Graulich
G4Beamline simulation
Use G4Beamline version 1.14b
Q1, Q2, Q3 off
Scan input proton momentum right after target, convert to momentum at B1
B1 and B2 tuned by G4Beamline to optimize proton acceptance.
Output the number of total events at GVA1 and GVA2
Input number of proton events: 5.6E9
CM 22 October 2008
Jean-Sébastien Graulich

8. D. Huang, MICE video conference
Pion production peaks at 160 A
Proton production peaks at 145 A
At 165 A, the ratio of Pion and Proton reaches the peak
D. Huang, MICE video conference

9. D. Huang, MICE video conference
Pion production peaks at 140 A
Proton production peaks at A
At 150 A, the ratio of Pion and Proton reaches the peak
D. Huang, MICE video conference

10. D. Huang, MICE video conference
Pion production peaks at 125 A
Proton production VERY close to zero
D. Huang, MICE video conference

11. Conclusion for Proton/Pion beam
Data / Simulation
Agree roughly
Proton cut off is observed at ~320 while expected at ~360 MeV/c
Need more refined simulation
We have settings for Proton or Pion beams at various momenta
CM22 October 2008
Jean-Sebastien Graulich

12. Quad Alignment studies
Preliminary analysis performed by Kevin Tilley
Mice Note in preparation
Beam Stop Removed
Dipole 1
CM22 October 2008
Dipole 2
Jean-Sebastien Graulich
CKOV A,B
TOF0

13. Method
Set B1 and B2
Scan current in each Quad, looking at mean position and sigma in the profile plot from TOF0
Profile Histograms were first obtained online from the online monitoring histograms
Offline analysis with G4MICE
From online monitoring
From G4MICE reconstruction 2D hit distribution in TOF0
V profile
H profile
Pions only!
TOF in TOF0
CM 22 October 2008
Jean-Sébastien Graulich

14. Jean-Sebastien Graulich
Q2 Scan
Not very instructive
Measurements for
Q1 and Q3 failed
CM22 October 2008
Jean-Sebastien Graulich

15. Jean-Sebastien Graulich
Q4-Q6 Scan
Optics check
CM22 October 2008
Jean-Sebastien Graulich

16. Jean-Sebastien Graulich
Q5 Scan
Y focussing effect clearly observed
Slight steering effect
Note that B2 was not reassessed
Limit value for Sig_X/Y = 40/sqrt(12)
For a flat distribution <X> is always 0, wherever is the beam center
CM22 October 2008
Jean-Sebastien Graulich

17. Jean-Sebastien Graulich
Q6 Scan
X focussing/Y defocussing effect clearly observed
Clear steering effect
Note that B2 was not reassessed
CM22 October 2008
Jean-Sebastien Graulich

18. Conclusion for alignment study
That was exploratory work, trying to find good observables
Desperate need for simulation for comparison
To be continued and improved
Need well defined plan for future measurements
CM22 October 2008
Jean-Sebastien Graulich