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BPTX publication on DIP and cogging
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Europe/Zurich
CCC-LPC (CERN)
CCC-LPC
CERN
Description
Discussion on Massi and Sophie's proposal for BPTX publication over DIP, synchro modes and cogging for startup.
PROPOSAL:
0) use DIP structure proposed in Alick's doc:
dip/EXPT/LHC/Timing
1) zLocationIP: indeed, change to DeltaT in ns
Purpose: value for OP/EiC to fine-adjust the crossing point
Definition: measure arrival time difference of paired bunches
(i.e. average over all bunch pairs __which are supposed to collide in
the given IP__ )
Rate: 1 Hz (or less frequent ?)
NB: this requires colliding pairs for a given expt to give a value.
NB: cogging will be verified with proper bunch scheme (with pairs
that are supposed to cross in IPs. We do not have anymore the
pressure of last year.)
2) PhaseB1 [ns]: phase difference between B1 (averaged over all bunches)
and bunch clock used by experiment.
Purpose: Monitor possible drifts which may lead to non-optimal detector
signal sampling. Offset to 0 as soon as experiment time alignment has been
performed.
Rate: currently 1 Hz, but maybe overkill for drift monitoring.
0.1 Hz or 1/minute would be enough. No ?
NB: drifts we are looking for are of the order of 100 ps, therefore
it is important that the published value be "baseline-subtracted"
to give a value which is not too far from zero (relative to 100 ps).
NB: if using BC, this automatically reduces value to <12.5ns,
and is independent of fill pattern. So, seems more appropriate
than ORB.
PhaseB2: same.
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