Daily Schedules and Hiccups

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Danny252
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Daily Schedules and Hiccups

Post by Danny252 » Tue Dec 01, 2009 1:53 pm

I'll keep this topic updated with the Daily Schedules that can be found in LHCb's Logbook. Maybe mention the odd hiccup too if it affects schedules

Tuesday 1st:

--
Comments: Collisions planned this week (for Experiments to play around with?) at 450GeV per beam.
Schedule is going as planned, they're preparing for ALICE's TED shots as I type (due in 8 mins)
--

- 08:00 Dump tests with beam
- 12:00 Short access (1 hour machine, 2 hours for UXs)
start pre-cycling machine

Afternoon/evening:

- 15:00 15 min of TI2 TED shots for ALICE, 30 min of
inject/circ and dump for RF checks
- 16:00 MPS BLM tests, including collimator moves
- 24:00 Aperture/kick response

Notes: - goal of the week: STABLE BEAMs, make collisions at 900 GeV
Last edited by Danny252 on Wed Dec 02, 2009 12:44 am, edited 1 time in total.

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Re: Daily Schedules

Post by Danny252 » Tue Dec 01, 2009 10:48 pm

Tuesday 1st Evening:

--
Comments: Just a lot of testing hardware, seemingly.
--

Afternoon/evening:
- MPS BLM tests, including collimator moves
provoke magnet trips (orbit correctors) check phase
space coverage of collimators

Night:
- Aperture/kick response

Look ahead:

Wednesday Morning:
- TDI set up, point 8, together with LHCb
- Q,Q' tuning, radial modulation, feedback Wednesday afternoon/evening:
- IR8 aperture 4 hours, then IR2 4 hours (incl BCM checks) Wednesday night:
- optics measurements, beta beating
Thursday morning:
- IR1 then IR5 aperture checks, 4 hours each (incl BCM checks)

NB: IR aperture checks in close contact with relevant
experiments

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Re: Daily Schedules and Hiccups

Post by Danny252 » Wed Dec 02, 2009 12:47 am

"18kV Drop at Point 1, 6 LHC Sectors Tripped".

Page 1 suggests 3 hours to fix, more info coming soon. Sounds like a superconductor problem of some sort

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Re: Daily Schedules and Hiccups

Post by Danny252 » Wed Dec 02, 2009 9:07 pm

Wednesday/Thursday:

--
Comments: Beam is not yet back as of 2200 CERN time, but they're getting there. Collimator testing is almost done, and there's talk of higher intensities (NOT Power!). More hardware/beam testing/tuning planned in the morning.
--

Evening:
now 1h access to UA (svc area at pt6) to upgrade firmware
of TSU (cure for asynchronous dumps due to simultaneous
unlocking of the two redundant units) 21:00 Expect beam back, start IR8 aperture with LHCb

Night:
01:00 Beta beating studies, circulating beams. Collimators
might go to parking position temporarily for part of
these studies, except TCTs.

Morning:
- TDI set up, pt8 together with LHCb
- LBDS golden orbit checks, verify new firmware
- Q,Q' tuning, radial modulation, feedback
- Aperture in IR2, IR5, IR1

Notes:
- Collimators (except TDI) have been set up fully according
to the design hierarchy. Cleaning efficiency > 99/9%.
Ready for higher intensity.
In order to go for STABLE BEAMS need to activate collimator
thresholds (then it becomes more difficult to change
collimator settings).

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Re: Daily Schedules and Hiccups

Post by Xymox » Thu Dec 03, 2009 2:33 am

GREAT idea...

I have turned this into a global thread... It will stay in the announcements. We will need to take the thread and store it away by date week by week and start a new one. Otherwise it will be come huge..

Great idea !

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Re: Daily Schedules and Hiccups

Post by Danny252 » Thu Dec 03, 2009 4:43 pm

Xymox wrote:GREAT idea...

I have turned this into a global thread... It will stay in the announcements. We will need to take the thread and store it away by date week by week and start a new one. Otherwise it will be come huge..

Great idea !
Thanks :)

Thursday:

--
Comments: More hardware testing, beam tuning, and so forth. Schedule seems to be holding well.
--

Morning:
- TDI set up, pt8 together with LHCb
- LBDS golden orbit checks, verify new firmware

Afternoon/evening:
- Q,Q' tuning, radial modulation, feedback
- Aperture in IR2, IR5, IR1, order to be defined (about 4h
per insertion region)

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Re: Daily Schedules and Hiccups

Post by Danny252 » Thu Dec 03, 2009 9:48 pm

Thurs Night/Friday Morning:

--
Comments: LBDS TSU - LHC Beam Dump System, Trigger Synchronisation Unit (mouthful or what?!). I think that this is a system that ensures the Beams are dumped together, or that the dumping system activates at the correct time.

MPS - Machine protection system - a systems (including things such as the Quench Protection System?) supposedly keeping the LHC in one piece. More hardware work/upgrades/testing?
--

Evening:
- Finish aperture in IR5, then IR2 then IR1,
about 4h per insertion region
- 2:00 separation bumps

Tomorrow:
- Need an access for LBDS TSU f/w upgrade
(1 hr + 2 h for precycle)
- 8:00 finish off aperture
12:00 MPS continued

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Re: Daily Schedules and Hiccups

Post by Danny252 » Fri Dec 04, 2009 1:56 pm

Friday Schedule (is probably out the window...)

--
Comments: DC Whitworth managed to pick up on a quench in sector 23 not too long ago (1223 is the earliest mention of this). I've not been able to find much info, but the LHCb's logbook mentions electrical problems being looked into - I can't tell if this is restricted to the LHCb or not.

For anyone who doesn't know, a Quench is the overheating of magnets/superconductors - potentially causing all sort of problems (i.e. September last year). However, this one seems fairly minor.

The 1600-1900 Access is currently moved back, and is going on until 1500 (about 7 minutes from now), since obviously no beams are moving. Cryo looks fairly stable at the moment.

I'd think the beams will be back up some time today (seeing as access is already being finished).
--

Morning/afternoon:
- Try the RF load balancing (see above).
- Continue MPS: BIS/dump tests, check phase space coverage
of collimators, 1-2hrs / beam, revisit IR1-H ?
Turn on dipole spectrometer bumps
Afternoon/Evening:
- 16:00-19:00 Access: LBDS TSU f/w upgrade, undulator,
wire scanners, + totem in shadow in s45 RomPots
- Access expected: 16:00-19:00 (+ 1.5 h for precycle)
Evening:
- chromaticity revisited
- Beam Instrumentatuion, PLL

NB: collimators to be set back in closed position
tomorrow morning

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Re: Daily Schedules and Hiccups

Post by Danny252 » Fri Dec 04, 2009 2:05 pm

COLLISIONS PLANNED THIS WEEKEND

Schedule at: http://lhc-commissioning.web.cern.ch/lh ... C-news.htm

Saturday 1600 - 450 GeV Beam Collisions, Intensity of 4e9
Sunday 0000 - As Above
Sunday 1400 - 450 GeV Beam Collisions, Intensity of 2e10

I believe the latter one will be the highest intensity collisions in the LHC so far, if they go ahead as planned!
Last edited by Danny252 on Fri Dec 04, 2009 2:21 pm, edited 1 time in total.

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Re: Daily Schedules and Hiccups

Post by NormReitzel » Fri Dec 04, 2009 2:20 pm

I wanted to amplify a bit on Danny's explanation of a Quench.

In superconducting magnetland, a quench, which is a sudden dischartge of energy from the circulating current of a magnet, can be caused by all manner of things, not just overheating.

What happens is simple - a section, often a very small section, of a superconducting line for some reason goes resistive. This is serious, at least as far as the field is concerned, because the resistive section starts to generate heat due to the high current in the superconducting loop. The resistive section spreads like an infection along the wire. The end result is sudden loss of superconductivity in the magnet coil, and this causes a precipitous discharge of the energy in the magnet. For multi-Tesla magnets, this is a lot of energy. Magnets have safety systems to permit this energy dump to (theoretically) dissipate more or less harmlessly into a bank of resistors. When the safety systems fail, that's bad, as we have seen.

Many things can cause a quench. Splices can be more sensitive than conductor runs, because the crystal boundaries in the splice aren't as nice as the ones in the wires. Another thing that can cause a quench is when a superconductor in a magnet at field actually moves. The mechanical stresses on the magnet coils are enormous, and to this end, the coils are usually embedded in something rock hard, like beeswax. When a field is being ramped up, increased mechanical stress on a winding can sometimes cause it to move, usually only a few microns. However, if the movement is enough, it can cause the superconducting wire to exceed the dB/dt for the wire, and it will lose superconductivity. Presto, a Quench.

This is the reason that Quench detection safetys are so all important.

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Re: Daily Schedules and Hiccups

Post by daavery » Fri Dec 04, 2009 2:31 pm

from the status report it looks like the quench was beam induced ( beam deviated and hit magnet coil ) this happened while they were "bumping" the beam to calibrate the beam cleaning systems and is probably not a real surprise. no time was lost since they were planning to shut down for access to the tunnel later anyway they just started the access after the quench

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Re: Daily Schedules and Hiccups

Post by Danny252 » Fri Dec 04, 2009 2:37 pm

Discussion topic for this quench: http://lhcportal.com/Forum/viewtopic.php?f=4&p=626

I'd like to keep this topic clean(ish) for the schedules and announcing problems - and keep discussion in specific topics (which helps people find all the info for either schedules or a specific problem in one place). Not that I'm saying the information posted above isn't appreciated :)

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Re: Daily Schedules and Hiccups

Post by Danny252 » Fri Dec 04, 2009 9:45 pm

Friday Night Schedule:

--
Comments: The LHC team have successfully put 2 bunches into one beam for the first time - each bunch is a group of particles orbiting in the LHC. In the end, they intend to use 2800 bunches.

Problems with the RF system in the LHC have held up further multi-bunch progress. The Radiofrequency System is used to accelerate particles within the LHC - this has been failing to start or cutting out during beams. Investigations ongoing by the RF team.

Collision timetables in the Collision Alert announcement.
--

Evening:
- Recover from access, pre-cycle
- ALICE solenoid to be ramped up now by CCC
- Dump checks in parallel with Beam Instrumentation
- Try bringing on the pt2 and pt8 spectrometer
bumps (LHCb field down, Alice "+" polarity).
Then leave the bumps on.
- Try two bunches in same beam

Night:
- Beta beating

Notes:
- peculiarity of IR1-H aperture scan to be studied
offline.
- undulator tests will be ongoing parasitcally
(find out if local bump needed to center the
synchrotron light)

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Re: Daily Schedules and Hiccups

Post by March_Hare » Sat Dec 05, 2009 8:11 am

Update on the schedule as on http://lhc-commissioning.web.cern.ch/lh ... C-news.htm:

Note that at the time of posting this here, it says above the schedule: "Following schedule to be re-done when length of 18 kV drop stop is known."

SAT
8:00 Re-establish machine reference - orbit, tune
9:00 Re-establish collimation
11:00 2 beam, setup, 4 bunch checks, extraction checks, collimators locked in position and gaps
16:00 stable single pilots - one per beam
17:00 450 GeV collisions, beam 4x4, 4e9
20:00 trial ramp plus pre-cycle
00:00 450 GeV collisions, beam 4x4, 4e9

SUN
8:00 Injection protection - tests for higher bunch intensity, beam: 2 pilots per beam
14:00 450 GeV collisions, beam ~2x2, 2e10
18:00 Ramp
0:00 SF
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Re: Daily Schedules and Hiccups

Post by gluon » Sat Dec 05, 2009 11:37 am

First 450 GeV collision of the day moved to 20:00 GTM.

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