Search found 161 matches

by Tau
Sat May 15, 2010 7:46 pm
Forum: The Accelerator
Topic: Current Events Discussion
Replies: 512
Views: 80930

Re: Current Events Discussion

And still, they could have more hits per rotation per experiment instead of three, so I an sure there must be more to these bunch numbers, otherwise I don't get it. Probably it has to do with bunch scheduling in SPS. This could also explain why they did four bunches recently. As you can see in http:...
by Tau
Thu May 13, 2010 1:36 pm
Forum: The Accelerator
Topic: The Hump
Replies: 20
Views: 7057

Nice paper found on hump

I just found a paper from end of 2009 that has very detailed information on chromaticity and the hump. They also talk about an 8 kHz oscillation that has been fixed in the mean time:
https://espace.cern.ch/acc-tec-sector/E ... _02_RS.pdf
by Tau
Mon May 10, 2010 7:59 am
Forum: Controversial topics
Topic: Several biggest errors of particle physicists.
Replies: 1135
Views: 227177

Re: Several biggest errors of particle physicists.

Probably he doesn't post anymore because he thinks he's dead by his own prediction... poor guy.
(Sorry Ivan, no offense intended; :D I just couldn't help making a joke after you scare the shits out of so many innocent people...)
by Tau
Tue May 04, 2010 6:41 am
Forum: Off topic
Topic: Music
Replies: 27
Views: 6041

"Official" music

Look at that! It looks like they are reading the forum.
There now is "official" LHC music at http://www.lhcsound.moonfruit.com/
by Tau
Mon May 03, 2010 12:47 pm
Forum: The Accelerator
Topic: Current Events Discussion
Replies: 512
Views: 80930

Re: Current Events Discussion

Reading through lots of documentation I get the impression that the higher intensity beams should have a better lifetime than the pilot beams. My guess is this is just a matter of adjusting the machine to the new intensity.
by Tau
Mon May 03, 2010 6:36 am
Forum: Controversial topics
Topic: Chelle goes on ...
Replies: 87
Views: 19874

Re: Chelle goes on ...

Xymox wrote:Everybody has very fixed opinions and feels they are 100% right.
That's why you don't meet many scientists over in this part of the forum. They are used to not being right. That's what we call progress.
by Tau
Wed Apr 28, 2010 12:26 pm
Forum: The Accelerator
Topic: A day at the LHC (movie)
Replies: 8
Views: 1952

Re: A day at the LHC (movie)

Looks like good educational material for new CERN recruits!
by Tau
Wed Apr 28, 2010 8:21 am
Forum: The Accelerator
Topic: Software or Hardware
Replies: 3
Views: 1296

Re: Software or Hardware

The LHC has so many controls (I estimate about a million) that have to be set in exactly the right way in exactly the right order. They do this in three steps: First they figure out how to set everything. Then they try this out by hand. Than they automate the procedure. This has happened for many, m...
by Tau
Tue Apr 27, 2010 8:47 am
Forum: Science
Topic: Luminance, luminosity, squeezing explained in English
Replies: 14
Views: 9939

Re: Luminance, luminosity, squeezing explained in English

From https://twiki.cern.ch/twiki/bin/view/At ... esults2010 I now know you get (at ATLAS, at least) about 60 000 events per inverse µbarn.
(Or, as physicist would say: the area of an event is 16 picobarn.)
by Tau
Mon Apr 26, 2010 4:51 pm
Forum: Science
Topic: Luminance, luminosity, squeezing explained in English
Replies: 14
Views: 9939

Re: Luminance, luminosity, squeezing explained in English

The luminosity unit is not so much "collisions" as well "collision opportunities". If you put enough protons through a narrow opening, they will collide. The probability of two protons colliding depends on physical properties (size, for example) beyond my grasp. But I bet that there is a not too har...
by Tau
Mon Apr 26, 2010 7:57 am
Forum: The Accelerator
Topic: COOL links
Replies: 57
Views: 20127

Nice series of movies

I am not sure if somebody already found these movies, but I like them:
http://www.collidingparticles.com/episodes.html

A bit off subject, but still nice reading is this article about the Tunnel Inspection Monorail: http://trshare.triumf.ca/~pac09proc/Pro ... rfp047.pdf
by Tau
Mon Apr 26, 2010 7:25 am
Forum: Off topic
Topic: Tea
Replies: 15
Views: 4762

Re: Tea

Plain, very hot, no milk, no sugar, take the bag out almost before you can taste anything. (So of my colleagues complain I drink "brown water", maybe I just have sensitive heatproof taste buds).
teacup.jpg
Tea cup
teacup.jpg (6.31 KiB) Viewed 4079 times
by Tau
Mon Apr 26, 2010 6:31 am
Forum: Science
Topic: Luminance, luminosity, squeezing explained in English
Replies: 14
Views: 9939

Luminance, luminosity, squeezing explained in English

Hi Folks, Having read lots of articles and questions about luminosity and luminance I will try to explain what I understood about it. Now that we have squeezed stable beams, this is becoming to be urgent. The problem is that most of the articles use lots of math :shock: , and this scares away intere...
by Tau
Sun Apr 25, 2010 6:51 am
Forum: The Accelerator
Topic: Current Events Discussion
Replies: 512
Views: 80930

Re: Current Events Discussion

Notice the second bucket in each beam does not line up (8941 vrs 8911); this will affect luminosity. There is a deeper reason behind this; it has to do with the asymmetry of the LHCb detector. For details, see http://blog.vixra.org/2010/04/24/lhc-achieves-stable-squeezed-beams/ . Update: there's no...
by Tau
Sat Apr 24, 2010 1:32 pm
Forum: Science
Topic: Let's go hump hunting!
Replies: 86
Views: 22152

Log entry about the hump

Today's (24 of april) log have more hump info. The most interesting is this, in the shift summary: Hump active from 7:30 - 9:50 then quite calm. In other words: the hump varies much more wildly than I thought! Looking further in the log, there was another "hump attack" from 17:40 to 18:10. So whatev...