Choose timezone
Your profile timezone:
Beta* and K-modulation
→
Europe/Zurich
6/R-018 (CERN)
----------------------------------------------
Per, "Q1 Magnet characteristics"
Reconstructing the k from wise during a modulation of 10A gives the same Delta K as Maria.
Uncertainty was claimed to be +-5 units (max) but...
Alignment data for 2015 is ready, easily 10mm in some MQX.-> To be sent by Per
Purpose misalignments are not available in the tables. -> Per can update this info into the tables.
Simulations cannot confirm measurements due to lack of the actual steel.
----------------------------------------------
Maria Kuhn, "K-modulation overview"
Action with Tobias: Check discrepancy between on-line model Delta K (Maria's value is OKed by Per).
Beta-beat at the IP up to 8%.
To consider misalignments also. Beta at the waists very consistent with design beta.
Measurements with crossing angle and separation, to be checked extact locations at quads.
Lumi imbalance 1% more for CMS.
How to make this on-line for commissioning beta* imbalance? -> To be discussed in December just
to have some input for Evian.
--------------------------------------------------
Tobias, "Corrections to beta* from xsing, tunes, and corrections"
Simulating the K-mod Q1, effect on tune with and without crossing angles: Qx=6e-6, Qy=2e-5.
The vertical corresponds to almost 1% correction in Qy. To be checked.
Effect of global corrections affect the waist by very little: 3 and 4 cm, very little-> Global corrections do not harm waist.
The effect of injection to collision tunes is very small.
Effect of local corrections, waist shift of up to 14cm, so the errors are there. Corrections need to be fine tuned wit Kmod.
Non-linear errors of triplet can be neglected.
0.5% cal. error in both Q1s would give a 23cm waist shift. -> Check what happens if we spread the cal error over
the entire triplet.
Only relevant points are: crossing angles and longitudinal misalignments.
Dispersion at the IP. In IP1 Disp ~ 0.02m (seems negligible but no data for IP5)
Key BPMs missing in IR5...
------------------------------------------------------------------
Ana, "Beta* measurements from amplitude information"
Some key Q1 BPMs were cleaned because of the tune, wrongly, too sctrict cut.
Calibration from 90m applied to 80cm measurements.
Beams 2 BPMs missing, flat data.
BPM R5 Beam always missing and most of the time missing for L5.
6 planes out of 8 measured with recalibrated amplitude info and good beta*.
------------------------------------------------------------------------------
There are minutes attached to this event.
Show them.