Daily Schedules and Hiccups

[Danny252]

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

CERN runs on GMT+1, actually

Saturday/Sunday Timetable

--
Comments: Multi-bunch beam and collision testing this weekend. Collisions happened 1300-1400, so no idea what's planned this evening.
--

Morning:
- Finish beta beating and dump tests
- 10:00 re-establish reference orbit, with ALICE and LHCb
spectrometer bumps.
- 11:00 re-establish collimator nominal protection

Afternoon:
- 13:00 two beams, set up , 4x4 4e9 checks, finish MPS
for stable beams

Evening/night:
- 19:00 two stable beams, single pilots, then dump
- 20:00 450 GeV collisions, 4x4, 4e9, several fills
of the order of 3 hours length

Tomorrow:
- morning: checks for higher intensity bunches
- test ramp late afternoon
- evening/night: continue with collisions

[Danny252]

Saturday/Sunday Schedule

--
Comments: Who knows what they'll actually do?
--

Evening/night:
- RF rearrange from 4 cavities to 6 cavities for B1.
- Flip polarity of ALICE solenoid to positive with
at least one beam circulating to check effect
(and correct if needed).
- Finish B1/B2 injection/dump protection:
* ongoing B2 check of async dumps, 30min more
* checks with 4 bunches in beam
(parasitic: BPTX experts can check RF buckets).
* Debunch test with both beams and 4x4
* ~3 hours to finish off
- 1h stable beams 1x1, no adjust, hands off
- ~20 min break before refill
- 4x4 refill, 4e9 bunches, then adjust ref orbit if needed,
transverse adjust each IP, then, and then only,
declare STABLE BEAMS. Then LHCf will move in.
No beam adjustements to be made after that without
going to ADJUST (use handshake). Preferably, no adjustements
at all. Observe stability overnight. Refills will be
done according to the agreed upon handshake mechanism.
Dump for refill, if needed, will be announced by phone
call and Page1.

Tomorrow:
- 9:00 meeting: review nightly events...
- morning: checks for higher intensity bunches
- test ramp late afternoon
- evening/night: continue with collisions

[Danny252]

Hola wonderful LCH Watchers, apologies for the lack of updates.

Monday:

--
Comments: Fairly large cryo problem at Point 4/Sector 45 (cryo screen has plenty of red). Page 1 predicts midnight for cryo to be back to normal - so this schedule probably went into the bin a while back.
--

- Access till 19:00 (update in afternoon).
- Set up SPS with few e10 intensity, bring beams
down the transfer lines (Pt2 and Pt8 closed).
- Re-establish beams, then STABLE BEAMS 4x4 6-7e9 p/bch
for the night.
- Keep taking data till ~8:00 tomorrow.
- Then, one hour of data with LHCb dipole off (change
in ADJUST at end of fill or with no beam and refill).

Look ahead:

- Alternate between STABLE BEAMS, studies for increased
intensity and trial ramps.

[gluon]

According to the e-logbook a glitch in the electrical network was at the origin of all this problems in the cryo systems.

Hope they learn how to avoid it in the future.

[Danny252]

Monday Night Schedule

--
Comments: Cryo recovery faster than predicted, precycling as I post this (2230). Mostly easily decipherable tonight
--

Evening:
- Recover from access, expect cryo back by about 22:00-00:00.
- Precycle.
- Put LHCb dipole back ON (same polarity as yesterday, B field
pointing down, "+" polarity)
- Put (or keep) ALICE dipole OFF
- Reverse ALICE solenoid polarity (from "+" to "-")

NB1: apparently the power glitch last night tripped LHCb and ALICE dipoles.
NB2: ATLAS toroids and solenoids are and stay off

Night:
- Re-establish beams.
- Stable beams 4x4 pilots of 6-7e9 p/bch.
- End of fill time to be decided around 08:30
- Then, short fill with LHCb spectrometer OFF.
Turn dipole back ON after the test (same polarity).
- Miscelleanous activities:
* RF phase adjustment for collision point.
* Transverde damper noise checks.

[gluon]

There's a cryogenics red alert for S56 (CS ITR5).

[DCWhitworth]

There's a cryogenics red alert for S56 (CS ITR5).

Yes I saw that, looks OK now.

[DCWhitworth]

There's a cryogenics red alert for S56 (CS ITR5).

Yes I saw that, looks OK now.

This is odd, different pages are showing different things. Cryo Page 1 shows red, HCC field page shows yellow and the Cryo Main Page for sector 56 shows green !

[gluon]

There's a cryogenics red alert for S56 (CS ITR5).

Yes I saw that, looks OK now.

This is odd, different pages are showing different things. Cryo Page 1 shows red, HCC field page shows yellow and the Cryo Main Page for sector 56 shows green !

Yeah, I saw those discrepancies too. I believe Cryo Page 1 shows circuits status for starting the beams and HCC shows status to maintain the beams.

[seabass]

not to sound pessimistic... but i wonder if electrical issues are going to be a recurring theme. I mean this thing needs a lot of juice and there are a lot of connections along with micronic resistance tolerances. It really is mind boggling how many things have to work together in order for this clock to tick. I think when you have such a complex collaborative experiment like this, complexity compounds on itself. my optimism lies in the brilliant troubleshooters that protonically drive this 17 mile subway.

[March_Hare]

My guess: yes, there will be more of this. Perhaps not all of it is new technology, but this machine is on a scale, humanity has never accomplished before.

Getting it all to work smoothly together and error free, is going to take some time.

[jmayes]

Problems will be a daily thing forever with something this size, just jump over and read a few pages of the Tevatron log (Fermilab) and you will see with even a mature machine like that they go through the same thing constantly. At least it's just tripping circuits and not making smoke!

I expect it will settle down quite a bit though.

J

[Xymox]

Hey Danny252 ??? where did ya go ?

This thread is getting ALOT of views...

[DCWhitworth]

not to sound pessimistic... but i wonder if electrical issues are going to be a recurring theme. I mean this thing needs a lot of juice and there are a lot of connections along with micronic resistance tolerances. It really is mind boggling how many things have to work together in order for this clock to tick. I think when you have such a complex collaborative experiment like this, complexity compounds on itself. my optimism lies in the brilliant troubleshooters that protonically drive this 17 mile subway.

Hopefully the Christmas shutdown will give them a chance to review the issues they have had and make some tweaks/changes to help reliability.

Of course there are always going to be issues. Even if you had 99.999% reliability in every component that would still give you lots of failures.

Protonically ? Great word, I must try and work this into my conversations

[Danny252]

It's schedule time! Wednesday's:

--
Comments: Seems stable multibunch beams are today's objective. Not as fun as collisions at >2TeV...
--

Morning:

- Re-establish beams
- 1h stable beams with LHCb dipole off, test transverse
steering in IP5.
- Continue with tests for higher intensity.

Afternoon/evening:

- Continue with tests for higher intensity, aiming for
a first stable beam fill with 4x4 2e10 p/bch starting
in the late evening.
- NB1: access (~2h) needed for abort gap keeper and
pt6 interlocked BPMs, before completion of higher
intensity studies.
- NB2: ATLAS magnets could start ramp up around 20:00