This website is no longer maintained. Its content may be obsolete. Please visit http://home.cern for current CERN information.
Injection - pilot
| |
Entry |
Exit |
| Safe Beam Flag |
True |
True |
| Beam Presence Flag |
False |
True |
| BIS |
UP overides |
UP overides |
| Injection BIS |
Extraction enabled |
Extraction enable |
The pre-injection setup sequence has been performed faultlessly. In the case
of
the pilot (no circulating beam) we have to verify absolutely that:
- everything is in the right state, with the right settings
- the dumps are fully functional
- all requisite safety systems are OK: QPS, PIC, software interlocks
During commissioning we can wait for persistent currents to decay to levels
where the multipole swings are acceptable or use the so-called degauss cycle. In the long run we will require dynamic correction of b1, b2, b3 via the
reference magnet system and/or experience.
Requirement: we have to track various parameters during the injection
plateau. Corrections for these will be predictions and/or empirically
established. How will we apply these corrections?
1. Download functions to the corrector power converters and trigger at the
start of injection.
2. Establish step-wise trim functions to be applied as trims at some fixed
frequency. This option would probably give us more flexibility.
Sequence
- Issue injection request
- Take PILOT. into BLUE (or YELLOW) ring
- Low level RF synchronizes transfer, jumps phase loop onto beam, switches synchro
loop on resynchronise the divider that provides the gating of the long. feedback
input/out to act on the incoming batch only function generator will raise
and then lower gain of longitudinal feedback. (Functions preloaded and
checked during Injection Setup) [Batch Dependent Settings][Timing]
- If beam circulates carry on. If beam doesn't - need to use case Establish
Circulating Beam.
- Measure (& correct if necessary): transverse injection
oscillations, Do we veto on injection
oscillation amplitude, energy offset?
- Measure (& correct if necessary): energy,
- RF feedback,
- Q,
- Q',
- separation at IPs,
- closed orbit.
- Is transverse damper working properly? Can
transverse damper issue veto if it can't damp sufficiently?
- Operator will have ability to trim corresponding physics parameters (tune,
chromaticity, orbit etc..) Note: real-time correction of these parameter,
use of corresponding actuators probably going on.
- Correct above if required. One issue is the need, or not, to incorporate
any trims made into the functions, firstly for the upcoming ramp and secondly
for the next fills. Address this issue in preparing to ramp.
- Adjust TDI with respect to closed orbit
- Adjust collimators with respect to closed
orbit (coarse positions). Worry about Beam size at collimators? Effect of beta
beating? Local orbit feedback? Emittance variations from SPS?