| Coupling | Orbit | Commissioning conclusion | ||
| ATLAS solenoid | Magnet length ~ 5.3 m. Max. field 2 T. Integrated field ~ 12 T.m Max. radial field 5 e-4 T |
Negligible | Can be neglected (1 microrad from crossing angle at 450 GeV) | Bring on and leave on after prefunctory checks at 450 GeV |
| ATLAS toroid | No effect on beam | As required by Atlas. | ||
| ALICE solenoid | Central field 0.5 T Max Radial field 20 e-4 T |
"The maximum field is ~ 0.5 T and it can be neglected." | Orbit kick from crossing angle at 450 GeV about 1 microrad - neglectable. Need radial field distribution to be sure but integrated field strength likely to be negligible. (12 m x 20 Gauss gives 16 microrad at 450 GeV). |
Bring on and leave on after prefunctory checks at 450 GeV. Don't worry about polarity changes. |
| ALICE dipole spectrometer field direction H kick V |
B.dl ~ 3 T.m ~ 130 microrad at 7 TeV |
- |
Dedicated commissioning at 450 GeV and in ramp. | |
| CMS solenoid | Magnetic length ~ 13.2 m |
At 450 GeV: delta cminus ~ -5i e-3 compared with tolerance of 0.03. Contribution relevant when solenoid is at full field at injection. |
With crossing angle on - vertical kick of ~ 5 microrad Integrated Bdl from radial field - negligible |
Measure and correct coupling at 450 GeV. Turn off for first ramp attempts - want to minimise effect of coupling on tune measurement. Check orbit when we bring on crossing angles. |
LHCb dipole |
B.dl ~ 4.2 T.m ~ 180 microrad at 7 TeV | - |
Dedicated commissioning at 450 GeV and in ramp. Have to repeat for operation with crossing angle and on change of polarity. |
ML November 2007
[1] Main reference "The effects of solenoids and dipole magnets of the LHC experiments", W. Herr, Chamonix 2006