|
Description |
Coupling |
Orbit |
Commissioning conclusion |
ATLAS solenoid |
Magnet length ~ 5.3 m. Max. field 2T.
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 |
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As required by Atlas. |
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ALICE solenoid |
Central field 0.5 T
Max Radial field 20 e-4 T
Magnet Length ~ 12 m. |
"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
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- |
Strong orbit distortion around the machine.
Compensation provided by 3 dedicated magnets -> closed, antisymmetric
bump |
Dedicated commissioning at 450 GeV and in ramp. |
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CMS solenoid |
Magnetic length ~ 13.2 m
Max. field 4 T ("significantly stronger that ATLAS")
Integrated field ~ 52 Tm
Radial field ~ 20 e-4 T at 1 mm from axis |
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. |
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LHCb dipole
spectrometer
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field direction V
kick H B.dl ~ 4.2 T.m ~ 180 microrad at 7 TeV |
- |
Strong orbit distortion around the machine.
Compensation provided by 3 dedicated magnets -> closed, antisymmetric
bump |
Dedicated commissioning at 450 GeV and in ramp. Have to repeat for operation with crossing angle and on change of polarity. |