Search found 12 matches

by daavery
Sat Dec 12, 2009 8:59 pm
Forum: The Accelerator
Topic: Why is one Beam Falling?
Replies: 6
Views: 3632

Re: Why is one Beam Falling?

The intensities fall because the beams are not perfect, they are being scraped by the collimators. Protons that are out of the center of the beam or off energy are continually being removed by the collimator system. what I find interesting is beam 2 is usually getting proton injections that are abou...
by daavery
Tue Dec 08, 2009 7:49 am
Forum: The Accelerator
Topic: Access Question
Replies: 3
Views: 2275

Re: Access Question

teh problen last year was that when the bad joint failed it opened the cryo pipes to the tunnel and flooded the are with huge amounts of He. till all the He was vented/removed the tunnels were not enterable
by daavery
Tue Dec 08, 2009 7:45 am
Forum: The Accelerator
Topic: Beams have bunches in wrong bucket; abort gap??
Replies: 10
Views: 6320

Re: Beams have bunches in wrong bucket; abort gap??

heres the latest description of the LHC filling pattern I have found:

http://cdsweb.cern.ch/record/691782/fil ... te-323.pdf
by daavery
Tue Dec 08, 2009 6:26 am
Forum: The Accelerator
Topic: Underground webcams
Replies: 40
Views: 15058

Re: Underground webcams

the system should be almost silent, the beam is in a vacumn, the protons weigh almost nothing. and sound from the collimator should be at some multiple of the beam revolution frequency ( 11245 hZ) which would be a high pitched squeal or ultrasonic. The dump would be a big bang ( dump lasts 88uSec ) ...
by daavery
Tue Dec 08, 2009 6:10 am
Forum: The Accelerator
Topic: Beams have bunches in wrong bucket; abort gap??
Replies: 10
Views: 6320

Re: Beams have bunches in wrong bucket; abort gap??

think of the buckets as cars in a railroad train. each beam has 2808 buckets in it. there is at least 1 gap between the end and the beginning of the train. that gap is the "abort gap". the gap is needed to allow the dump steering magnet to switch from off to on during a time when there are no partic...
by daavery
Tue Dec 08, 2009 5:41 am
Forum: The Accelerator
Topic: Beam Xover questions
Replies: 11
Views: 5499

Re: Beam Xover questions

in most of the ring the beams are side-by-side in 2 beam tubes. in the experiment areas the 2 tubes merge into a single tube. once the beams are "stable" the paths of the 2 beams are slowly steered so they cross at the desired crossing point in each experiment area. that continues as a steady state ...
by daavery
Sat Dec 05, 2009 8:19 pm
Forum: The Accelerator
Topic: Weekend of 12-3-09 collision events !
Replies: 188
Views: 54701

Re: *** COLLISION ALERT ***

It looks like they are plotting the "programmed beam energy" which is displayed at the top center of the page. that way the plot shows both beam intensities and programmed energy.
by daavery
Fri Dec 04, 2009 2:31 pm
Forum: The Accelerator
Topic: Daily Schedules and Hiccups
Replies: 41
Views: 17770

Re: Daily Schedules and Hiccups

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...
by daavery
Wed Dec 02, 2009 2:22 pm
Forum: The Accelerator
Topic: What does ... mean?
Replies: 28
Views: 20935

Re: What does ... mean?

point 4 (RF) is the RF injection point, the RF energy is what accelerates the beam

beam cleaning basically scrapes the particles of the beam that are spread outside of the core beam away, so that the beam cross-section stays constant
by daavery
Wed Dec 02, 2009 9:48 am
Forum: The Accelerator
Topic: 12/2/09 power loss and many systems down
Replies: 25
Views: 16003

Re: *** MAJOR power loss and many systems down

there are some pictures of the damaged wire ends in the morning briefing pptx file

http://lhc-commissioning.web.cern.ch/lh ... 21209.pptx
by daavery
Tue Dec 01, 2009 3:22 pm
Forum: The Accelerator
Topic: Old Breaking news 11/30-12/2/09
Replies: 20
Views: 13204

Re: *** Breaking news ***

Page1 format has also changed: the beamTV images are not showing now and the whole mid-page area is different ( blank for now). I also noticed the "Page 1" and "LHC Operations" " Beam Current"(I) values were very different since yesterday. The "LHC Operations" I values seemed to match the Intensity ...
by daavery
Mon Nov 30, 2009 4:31 am
Forum: The Accelerator
Topic: Breaking news 11/23-11/30 09
Replies: 17
Views: 8184

Re: *** Breaking news ****

from CERN twitter:

# A new record. Both beams in LHC reach 1.18 TeV at 00:42 on 30 November. about 4 hours ago from web