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Vertical deflection, 0.85 mrad, integrated field 1.2 Tm. PFN voltage 54 kV. Four fast pulsed magnets per ring. Magnets between Q4 and Q5.
Safe injection in LHC Etienne Carlier Cham XII
Other issues
Do you have already an idea on how many set of settings (kick enable, kick
strength, kicker delay and kick length) you would like to have for
the LHC injection kickers?
- One single set for all the injection (a la LEP). This option is possible as
the last batch will be a long batch.
- One set for the first injection, one set for next injection and one set for
last injection (first, next and last injections will have do be
managed through timing event)
- One set per injection (injection number performed will have to be identified by a timing event)... how do we identify the different injections?
After discussion with Volker and Laurent, a simple back-of-the-envelope calculation (based on measured failure rates) shows that we expect
something of the order of one event over a 20 year LHC lifetime where the full injected beam will impact the primary collimator jaws, due to a
flashover in the MKI magnet cells.
TDI position: 4.38 +/- 0.3mm (8.5 +/-0.58 sigma)
Primary collimator setting: 6 sigma
Total injected high intensity batches in LHC lifetime: 20 (years) x 200 (days) x 2 (rings) x 2 (fills) x 12 (batched) = 2 e5
4 MKI magnets per injection: 8 e5 magnet pulses in LHC lifetime
Measured MKI flashover rate is 2(+/-2) flashovers per 4 e5 pulses, so assume a rate of 1 per 1e5 pulses, i.e. 8 flashover events in LHC
lifetime.
Average deflection per MKI is 18 sigma, for 33 cells, or 0.55 sigma/cell
A flashover at cell N produces x2 kick in first N cells, zero in remainder
So flashover needs to happen in cell 8 - 11 for the batch to get a dangerous kick
(where the total is missing between 6 and 9 sigma) i.e. probability is 4/33.
Therefore total number of dangerous events during LHC lifetime is 8 * 4/33 = 1.