Search found 161 matches

by Tau
Fri Jul 01, 2016 7:21 am
Forum: The Accelerator
Topic: Interesting dump cause today
Replies: 1
Views: 1195

Interesting dump cause today

After a sequence of unplanned beam dump that were unsurprisingly all caused by disturbances on the power grid, there was an interesting dump this morning, which was caused by the internal dump trigger. Short explanation: To make sure the beam energy is disposed of safely, there is a dump system. The...
by Tau
Thu Jun 30, 2016 11:13 am
Forum: The Accelerator
Topic: 30,000 AMPS, WOW!
Replies: 11
Views: 4305

Re: 30,000 AMPS, WOW!

A-hahahah really wow !!!.. Well inductance is might hard to deal with. Resistance is easy... 15 Henries is insane A quick calculation: energy in coil = 1/2 * inductance * current^2 so at 30 kA and 15 H we have 6750 MJ. The coil will have that much energy at its avail to make sure the current keeps ...
by Tau
Tue Jun 28, 2016 9:13 am
Forum: The Accelerator
Topic: What are the current records for LHC fills?
Replies: 45
Views: 11430

Re: What are the current records for LHC fills?

sciing wrote:All records in one fill, longest fill after 37h operator dump. Finally 737/pb for ATLAS and 710/pb for CMS.
And then, in four hours and three minutes, we are back in business! That's not the record, but in combination with the fill length we have over 90% stable beams.
Not bad at all...
by Tau
Sun Jun 26, 2016 6:56 am
Forum: New Users Start Here
Topic: Hi!
Replies: 2
Views: 1755

Re: Hi!

chardo137 wrote:Hi all!
Don't be intimidated by the math/physics gurus. They will answer anything you ask.
Really!
by Tau
Sun Jun 26, 2016 6:04 am
Forum: The Accelerator
Topic: What are the current records for LHC fills?
Replies: 45
Views: 11430

Re: What are the current records for LHC fills?

And, after some "interesting" troubles last week, we are getting another record fill: 5043. As I write this, we already have .55/fb. Reading tip, not for the faint of heart: if you are not afraid of some though math, this article shows exactly what are the troubles of the ADJUST phase (I never under...
by Tau
Sat Jun 18, 2016 9:36 pm
Forum: The Accelerator
Topic: CMS and ATLAS luminosity: are they jealous?
Replies: 6
Views: 2482

Re: CMS and ATLAS luminosity: are they jealous?

On page 66 of the LHC presentation on Monday at LHCP 2016 Sweden, it states the Atlas luminosity is 3% too high, CMS 4% too low: https://indico.cern.ch/event/442390/contributions/1096117/attachments/1289665/1920065/LHCP16_EM.pdf That is a very interesting presentation. I learned a lot more than the...
by Tau
Wed Jun 15, 2016 5:54 pm
Forum: The Accelerator
Topic: CMS and ATLAS luminosity: are they jealous?
Replies: 6
Views: 2482

CMS and ATLAS luminosity: are they jealous?

You probably noticed that CMS always seems to get a little less luminosity than ATLAS. In the latest fills, I noticed CMS is always a bit earlier (one or two minutes) with taking data so that during the first few minutes or so, their integrated luminosity is higher than ATLAS. Of course, with ATLAS ...
by Tau
Wed Jun 15, 2016 5:23 pm
Forum: The Accelerator
Topic: LHC logbook access
Replies: 7
Views: 3937

Re: LHC logbook access

mfb wrote:You don't need any account for the morning meeting slides as far as I know.
Yes, that's true :oops: . Sorry for the confusion.
by Tau
Tue Jun 14, 2016 6:40 am
Forum: The Accelerator
Topic: LHC logbook access
Replies: 7
Views: 3937

Re: LHC logbook access

Yes, a lightweight account works fine for the logbooks. I have mine for years and I forgot how I got it, but I can guarantee you that it works.
And, the logbook is a nice source of information. Another good source is indico morning meetings, that are also accessible with the lightweight account.
by Tau
Tue Jun 14, 2016 6:30 am
Forum: The Accelerator
Topic: Other examples of bad luck?
Replies: 2
Views: 1339

Re: Other examples of bad luck?

My personal "favorite" is this incident that happend in November 2009. Not much delay, but a good story;
https://cds.cern.ch/journal/CERNBulleti ... es/1221806
by Tau
Mon Jun 13, 2016 10:01 am
Forum: The Accelerator
Topic: Dashboard tune plots seem... out of tune?
Replies: 4
Views: 1348

Re: Dashboard tune plots seem... out of tune?

The red line is not as problematic as the other lines (it just means horizontal and vertical tune are the same). If it hits one of the other lines, I don't think they can keep the beam. It is not as hard as you think. The red line indicates where horizontal and vertical tunes are the same. That mea...
by Tau
Mon Jun 13, 2016 9:49 am
Forum: The Accelerator
Topic: What are the current records for LHC fills?
Replies: 45
Views: 11430

Re: What are the current records for LHC fills?

With only a bit of trouble between fills, there's another one going on.
If thing stay going this way, we are going to break the "maximum luminosity per week" record.
by Tau
Fri Jul 31, 2015 5:32 am
Forum: The Accelerator
Topic: 2014 machine commissioning and 2015 start up
Replies: 59
Views: 61942

Re: 2014 machine commissioning and 2015 start up

Does 25ns scrubbing also involve machine development at the same time that will ultimately aid the intensity ramp up? Yes, getting those scrubbing beams in is quite a challenge. For scrubbing to be effective, they like high intensity. Now they are using "doublet" beams that consists of pairs of bun...
by Tau
Fri Jun 19, 2015 8:11 am
Forum: End Of The World
Topic: Asteroid Apocalypse End Of The World In September 2015
Replies: 8
Views: 8782

Re: Asteroid Apocalypse End Of The World In September 2015

draph91 wrote:oh goody, ANOTHER end of the world prediction
It is not even on the list yet. Who feels like adding it?
https://en.wikipedia.org/wiki/List_of_d ... tic_events
:D
by Tau
Sat Jun 13, 2015 12:58 pm
Forum: New Users Start Here
Topic: back again
Replies: 2
Views: 1479

Re: back again

Welcome to the forum!
It is nice to see how many newcomers take a look now the machine is running again.