Machine
coordinators Roger Bailey and Gianluigi Arduini
Day |
Date |
Beam |
No beam |
% |
Monday |
23-Nov |
24 |
0 |
|
Tuesday |
24-Nov |
6 |
18 |
|
Wednesday |
25-Nov |
2 |
22 |
|
Thursday |
26-Nov |
9 |
15 |
|
Friday |
27-Nov |
3 |
21 |
|
Saturday |
28-Nov |
21 |
3 |
|
Sunday |
29-Nov |
24 |
0 |
|
Week48 |
Beam/Nobeam |
89 |
79 |
53 |
Status Monday morning
Both beams
captured
Instrumentation
commissioning well advanced
Beam 1
·
RF
phase adjusted and phase lock loop on
·
Lifetime
5-10 hours
·
Orbit
Q Q’ dispersion all look good
·
Coupling
and beta-beat need correction
Beam 2
·
RF
phase adjusted
·
Lifetime
3 hours
·
Orbit
Q Q’ coupling measured and corrected
Outstanding issues
·
Pre-cycling
circuits still causing problems
·
Still
teething problems with new QPS system which is active on sector 12
·
Beam
dump synchronisation (with RF re-phasing)
·
No
beam Tuesday afternoon (Radiation survey in the injectors)
·
Access
in LHC before and during this
o
QPS software
upgrade on 600A systems all around the machine
o
Try to
limit access beyond this (some hope!)
Progress
Beam 2 brought to
the same level as Beam 1 (Monday morning)
·
Both
beams with RF phase locked
·
Orbit,
Q, Q’, coupling OK to first order
·
Lifetimes
10 hours
·
Dispersion
excellent
·
Beta-beat
measured
Two beam runs
(Monday afternoon)
·
Beams
steered with BPMs interpolated to IP, successively IP1, IP2,
IP8, IP5
·
Collisions
in ATLAS, ALICE, LHCB and CMS
First test ramp
(Monday midnight)
·
Beam
to around 540GeV
·
Lost
due to tune drifting
Scheduled access
given Tuesday morning for machine wide QPS
modifications
Many other
interventions for a variety of things
Difficult recovery
overnight Tuesday/Wednesday (many subsequent interventions needed for QPS)
Operation with
beam then further held up by
·
a
problem in LHC cryogenics in Sector 12 (Wednesday 09-19)
·
a
vacuum leak in the PS (Thursday 02-16)
Just 2 hours of
beam between Tuesday morning and Thursday afternoon
However
significant progress made with LHC superconducting circuit cycling
LHC precycle now
working
This allows
operation to re-establish a reproducible machine magnetically
Restarted with
beam Thursday evening 17.00
Beam 2 injected
without problems. Tunes come
back to how they were yesterday.
Beam 1 problems to inject
·
Uncertainty
of TCDQ position
·
RF
synchronisation problems
·
Beam 1
injected around 22.30
Energy matching
done using beam 2, then verified with beam 1
Frequency changed
106Hz and SPS energy increased 250MeV, then TI2 and TI8 trimmed to match
Looks good, as can
be seen on first turn trajectory Beam 2,
orbits Beam 1 and Beam 2
Operation with
beam then stopped again, due to a problem with LHC cryogenics in Sector 34
Cryo back at 18.00 Friday
but problems to get all 600A on due to QPS issues ...
Finally
all (needed) circuits OK at 23.00
Struggled with the injection interlock system. Beam in around 01.30
Overnight
·
Re-established conditions for beams 1 and 2
·
Kick response beam 2 (sectors 12 23 34 45 done)
·
Beam dumps due to beam loss when starting S56
·
PS off from 04-07
Beam dump studies
started at 08.00 Saturday
·
Synchronisation
checked with beam by scanning RF bucket through sweeps for B1 and B2
·
Protection devices and aperture scans
o
Aperture scanned for B1 extraction channel
o
Apertures look similar to those obtained for B2 on Monday
o
Physical apertures seem OK on both planes
·
Verification
of the protection in case of
asynchronous dump
Operations
measurements and tuning in the afternoon/evening
·
Orbit
o
Reference orbit B1 and B2 using common correctors
·
Tune,
coupling and chromaticity measurement and correction
o
C_
down to ~0.005 (Beam 1)/0.0025 (Beam 2) after correction
·
Chromaticity
o
Measured values from +- 100, 50,0 trims off ref
Beam 1 è Q’H=+5 - Q’V=+7
Beam 2 è Q’H=+9 - Q’H=+8
·
Undulator RU.L4 ON at 50 A
o
no
effect on orbit/tune (Beam 2) è but not sufficient to see synch light è HW commissioning to be continued
BI
systems commissioning in parallel through the afternoon/evening
·
phased
in horizontal and vertical MKQA tune kicker for B1 and B2
·
measured
and corrected PLL beam transfer function for B1 and B2 system (B2 requires some
polarity/mapping checks)
o
tested
continuous radial modulation via the orbit feedback controller and verified
switch on/off procedures, frequency and amplitudes behaviour
o
performed
initial PLL lock studies with B1, initial results look very promising, further
assessment w.r.t. nominal PLL performance
(bandwidth/sensitivity to resolve dp/p changes in the
order of 1e-5) is needed
o
performed
semi-automatic chromaticity
measurements and preliminary tune modulation/de-modulation studies in view
of continuous Q' tracking -> some FESA/SW issues have been identified that
need to be addressed
·
Not
yet ready for tune/chromaticity feedback
Beta-beating
studies overnight
·
The
beta-beating in beam2 was very different to the beta-beating measured before
the ramp (most likely due to the lack of precycling
then).
·
For
Beam1 the initial beta beating agrees with the measured after the ramp (Friday
00:00 am), proving no changes in time with proper pre-cycling.
·
The first
local error was found and successfully corrected in IP2 (MQXB2.R2 + 7e-5 and
MQXB2.L2 -5e-5).
o
A
reduction of the peak vertical beta-beating in beam 1 of 10% was observed.
o
No
change was observed in the peak b-beat in beam 2 and the horizontal of beam1.
·
We
removed all the trims and re-measured the initial conditions without observing
any change (no hysteresis effects).
·
Another
study in IP7 was started but due to lack of time and frequent beam absence was
not conclusive.
Collimator set up Sunday
·
BEAM1:
o
All IR3, IR7 to nominal settings (primary aperture about 5.7 sigma)
==> multi-stage collimation is set up
Dump protection IR6 set up
TCT's in IR1 cross-checked: rough setting confirmed
Other TCT's not touched: at +-15 mm around +-15-25 sigma
·
BEAM2:
o
All IR3, IR7 to nominal settings (primary aperture about 5.7 sigma)
==> mutli-stage collimation is set up
Dump protection IR6 set up
TCT's not touched: at +-15 mm around +-15-25 sigma
·
Additional tests:
o
Check on interlock threshold for tungsten collimators (see logbook
entry)
Movement and beam loss response check for vertical Roman Pots, beam1
Summary
of the (shortened) MPS tests
·
Tested the reaction time of the FMCMs on RD1.LR1, RD1.LR5,
RD34.LR3, RQ4.LR7 by switching off the PCs (to avoid a
WIC trigger that is even faster than the FMCM in such a case). In all cases the
FMCM dumped the beam before any BLM triggered.
·
Checked the reaction of the BLMs by trimming RD1.LR1 and RD1.LR5
by a small step (also to be able to analyze with PM data). In those cases the
BLMs in IR7 triggered the dump.
·
Tested the SIS interlock on orbit correctors using a long bump
over the arc R2-L3. SIS triggered the dump while the bump was ramping up.
·
All MPS tests were successful - excellent performance of the
FMCMs.
Second LHC ramp
·
Beam
to 1.04TeV
·
Lost
due to tune drifting
·
Orbit difference wrt
reference and orbit evolution
during the ramp
Third LHC ramp
·
Tunes
for beam 1 were different when we returned to injection energy (no precycle)
·
Trimmed
and incorporated
·
Ramped
2 beams, all the way to 1.18TeV !!