typodupeerror

## LHC Fully Documented Online239

Posted by kdawson
from the twenty-seven-kilometers-of-documentation dept.
Physicser writes "Want to read every single technical detail of the design and construction of the Large Hadron Collider and its six detectors? The whole shebang — seven reports totaling 1600 pages, 115 MB, with contributions from 8000 scientists and engineers — has been published electronically by the Journal of Instrumentation, free to read without a subscription."
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## LHC Fully Documented Online

• #### I would but.... (Score:5, Informative)

on Monday August 25, 2008 @11:59PM (#24747101)
It would be a great read if I was one of the ten people on the face of the planet who could actually understand every detail. Oh, sorry, that's the people who wrote it.

I know it's going to get downloaded a ton of times and probably deleted before most readers ever get to the 3rd page, if it's even read at all.

Save them poor guys some bandwidth, torrent it. Too many people are going to be wasting their resources with no serious intentions of reading the contents.
• #### Re:Want to read every single technical detail...? (Score:5, Informative)

on Tuesday August 26, 2008 @12:10AM (#24747211) Homepage Journal

Hint: click on the word "abstract". It's turtles all the way down.
• #### Simple introduction... (Score:5, Informative)

<gro.4level' ta' `ecnareviled'> on Tuesday August 26, 2008 @12:35AM (#24747397) Journal
It's a hobby, I'm way outside of the brainpower to do the math.

So I found some videos and articles to help me out: YouTube [youtube.com] to the rescue [youtube.com] Warning there's some crap with bird in there.

Finding the Higg's Boson is the big prize, if they find it it will help with this which disrupts the notion of black holes as "singularities" and raises some philosophical, and religious questions... largely if the theorized particle is not found. [wikipedia.org]

Also interesting is the evaporating black hole theory, which is all but proven so don't worry (Cough CNN).

Personally I've always been facinated by Virtual particles [wikipedia.org] and am curious about the implication of examining non-singularity black holes.

Enjoy it, it's gonna be cool as hell!
• #### Re:I found a vulnerability... (Score:4, Informative)

on Tuesday August 26, 2008 @02:07AM (#24747963) Homepage

Now that we're venturing out into the realm of "extremely offtopic," I should point out that Americans have no idea what gaffer tape is, unless they've worked as a roadie or stage tech at some point in their lives.

For those of you who still don't know what gaffer tape is, you may substitute "duct tape" to sufficiently understand the parent poster's humor.

However, gaffer tape is far superior to duct tape in many aspects. It's made from cloth, rather than plastic, and doesn't tend to destroy whatever surface it happens to be applied to. It can generally be removed without causing damage, despite being nearly as strong (if not stronger) than duct tape.

• #### Re:I would but.... (Score:5, Informative)

on Tuesday August 26, 2008 @02:47AM (#24748147)

"Abstract. The TOTEM Experiment will measure the total pp cross-section with the luminosity-independent method and study elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, will be installed on each side in the pseudorapidity region 3.1 || 6.5, and Roman Pot stations will be placed at distances of ±147 m and ±220 m from IP5. Being an independent experiment but technically integrated into CMS, TOTEM will first operate in standalone mode to pursue its own physics programme and at a later stage together with CMS for a common physics programme. This article gives a description of the TOTEM apparatus and its performance."

The TOTEM experiment will measure the total pp (proton-proton) cross-section (probability of collision) with the luminosity-independent method (does not depend on the amount of incoming particles) and study elastic and diffractive scattering (particle and wave scattering) at the LHC. To achieve optimum forward (close to the beam-pipe) coverage for charged particles emitted by the pp collision in the interaction point (where the beams cross) IP5, two tracking telescopes (planes of silicon or something that can detect charge particles), (named) T1 and T2, will be installed on each side in the pseudorapidity (the angle above the beampipe) region 3.1 (~5 degrees) || 6.5 (1 degree), and Roman Pot stations (to measure the luminosity) will be placed at distances of +- 147m and +-220m from IP5 (those distances from where the particles collide). Being an independent experiment but technically integrated into CMS (the Compact Muon Spectrometer), TOTEM will first operate in standalone mode to pursue it's own physics programme...

• #### Re:I would but.... (Score:5, Informative)

on Tuesday August 26, 2008 @03:41AM (#24748425) Homepage
Okay, why not...
• pp: proton - proton
• cross-section: particle interaction rates are measured using "cross section". Imagine a billiard ball colliding with another a billiard ball. The cross section is just it's area seen from one side: pi r^2. But quantum particles are not hard solid spheres and can pass through each other, resulting in cross sections much smaller. The unit here is the "barn" = 10^-28 m^2. The total p p cross section is about a milli-barn. Higgs is about a pico-barn. Z bosons are about a nano-barn.
• luminosity: inverse of a cross section. This is how we measure the amount of data. It is the "intensity" of the beam. (luminosity)*(cross section) = number of (expected) collisions. The LHC is expected to collect about 1 inverse femtobarn in the first year of operation, and 300 total.
• elastic scattering: p p -> p p. Used to measure luminosity. (TOTEM's primary function)
• diffractive scattering: p p -> p p + X. This has been proposed as a high precision but low rate way to detect the X=Higgs. In this scenario, TOTEM sees the final p p and X ends up inside the CMS detector. (TOTEM's other primary function)
• pseudorapidity: a measure of angle: \eta = -ln \tan \theta/2. At \eta=\infinity, \theta=0 and at \eta=0, \theta=90 degrees. Pseudorapidity has nicer properties under Lorentz Transformations [wikipedia.org] than angle.
• Roman Pot: a particle detector device which is lowered into the beam line to detect particles traveling very close to the beam. It detects protons scattered by very small angles.

There's a reason a Ph.D. takes 4-6 years. Gotta learn all this.

P.S. TOTEM is one of the minor experiments. Now go read about CMS and ATLAS. :)

Disclaimer: I am an American theoretical physicist at CERN.

• #### Re:Want to read every single technical detail...? (Score:2, Informative)

on Tuesday August 26, 2008 @03:52AM (#24748473)

Or you could watch this TED lecture [ted.com] for a nice explanation:

• #### Re:I would but.... (Score:5, Informative)

on Tuesday August 26, 2008 @09:28AM (#24750385) Homepage
yes. [symmetrymagazine.org]
• #### Re:I would but.... (Score:3, Informative)

on Tuesday August 26, 2008 @09:33AM (#24750459)

Apparently, yes. But it's not complete ironic as we might imagine, as the uranium nucleus is comparatively larger than other elements:

http://en.wikipedia.org/wiki/Barn_(unit) [wikipedia.org]
http://www.symmetrymagazine.org/cms/?pid=1000258 [symmetrymagazine.org]

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