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Do they HAVE to do a precycle every time?

Do they have to ramp the field all the way down to zero? They could stop at 450 GEV and start loading again?

Well, it seems that they have stopped at 300 GEV; well below 450. I guess that are would like to start another cycle very soon !

"RECOVERING FROM RAMP". Now what is that? Too many emotions for one night!

I guess the action is over for tonight.

In any ways: well done guys... I wish I had been there with you.

See you tomorrow.

Does anyone know if they have done any collisions at all? Just some tests or anything?

I don't think the detectors are ON at this point: just "standby".

Wallmott wrote:Does anyone know if they have done any collisions at all? Just some tests or anything?

No, collisions are not currently taking place. I think they're planning on doing them on the 30th. Collisions at 3.5 TeV per beam will be a pretty momentous event so I think CERN are trying to control exactly when it happens.

amiso wrote:Do they HAVE to do a precycle every time?

Do they have to ramp the field all the way down to zero? They could stop at 450 GEV and start loading again?

Yes they do in order to maintain consistency. The magnets in the machine have a memory and have to be precycled between each fill in order to get rid of it.

Since this is a precision instrument they need to start from a consistent point with each fill or otherwise the data about machine performance will not be relevant from run to run.

Today is March 31th. Did they try the "squeze" procedure yet. Did someone see this status displayed? I recall that they go thru the following sequence:

x--precycle
x--inject
x--prepare for ramp
x--ramp up
x--flat top
--squeeze << not done yet
--adjust << not done yet
--stable beams << DETECTOR INTO ACTION : not done yet
x--ramp down
x--recover (and go to sleep! )

Also, I have noticed that the real action stuff happens during the night shift! That makes real sence to me...

Just checking back in, looks like one beam has been at 3.5TeV for over 2 hours! That's some pretty good stamina. They say the op page is frozen so I guess the 12+ hours of 3.5TeV beam time it shows is not correct?

Anyone have a current, correct report on how long it has actually been going?

Can't wait for the 30th!

According to the logs beam 1 was dumped due to some sort of system sensitivity and currently there is no beam coming from the PS so they can't reinject so they are sticking with doing extra measurements on the one beam they have right now.

Looks like the current beam has been circulating for about four hours. All Ops pages look OK to me just the scales are a little odd.

I wonder why, before they ramp down, the energy goes even higher for a while.

Does one of the Meltronix displays show information about the particle bunches?

Thanks,
.mike

Well still a longevity record in my book, shows the magnets are ready for 3.5!

Tx for the update

Cryo issues in 56 caused an emergency dump around 0830. Oddly, 34 is now showing up red (although as it's now access, this may be intentional) with 56 as green. Another plan out the window I guess

@ mexaly the OP-Vistar LHCCONFIG http://op-webtools.web.cern.ch/op-webto ... =LHCCONFIG will have the beam bunch info I believe once things settle down and commissioning is over in a week or so. Old mel has it on the lower right corner of the LHC lite display. http://meltronx.com/lhclite/