Slashdot Mirror

I seem to recall the www phenomenon began because some guy thought that exchanging physics info would be a good idea.

http://public.web.cern.ch/public/en/About/Web-en.html

I publish. I get the copyright and blog quality arguments ad infinitum - but I think the real issue is simply being missed here.

http://lhc.web.cern.ch/lhc/

You know, it's funny that the CERN is argumenting that the gamma rays do no harm as a "proof" that their gigantic machine will not destroy the solar system, while there are other scientists that say that the same rays caused extinction in the planet.
Quote:
Accelerators recreate the natural phenomena of cosmic rays under controlled laboratory conditions. Cosmic rays are particles produced in outer space in events such as supernovae or the formation of black holes, during which they can be accelerated to energies far exceeding those of the LHC. Cosmic rays travel throughout the Universe, and have been bombarding the Earth's atmosphere continually since its formation 4.5 billion years ago. Despite the impressive power of the LHC in comparison with other accelerators, the energies produced in its collisions are greatly exceeded by those found in some cosmic rays. Since the much higher-energy collisions provided by Nature for billions of years have not harmed the Earth, there is no reason to think that any phenomenon produced by the LHC will do so.
Cosmic rays also collide with the Moon, Jupiter, the Sun and other astronomical bodies. The total number of these collisions is huge compared to what is expected at the LHC. The fact that planets and stars remain intact strengthens our confidence that LHC collisions are safe. The LHC's energy, although powerful for an accelerator, is modest by Nature's standards.

Now I don't know what to believe.

Gravity is actually the weakest of the forces and the one that is most difficult for scientists to quantify, model or test, even Large Hadron Collider, LHC will not do it. The reason we think we understand gravity is because it is long-range like the electro-magnetic force and theyare easily sensible to us unlike the other two forces, weak and strong nuclear forces which are too short ranged.

CERN is not a linear accelerator, it is ring shaped.

The effect of increasing CO2 in the atmosphere may be much smaller than most scientist claim. A number of scientist are looking at other causes for the increased global temperature, among them a team at CERN http://public.web.cern.ch/PUBLIC/en/Research/CLOUD-en.html who are looking at the correlation between cosmic-rays and low cloud cover.
http://en.wikipedia.org/wiki/Henrik_Svensmark has written a understandable book about this correlation and the effect on the global temperature which is well worth the read if you are interested in discussing the subject based on scientific research.

we've been talking about antiparticles for decades (has one of our colliders actually made one yet?), you talk of photons spontaneously appearing out of nothing, and nobody has ever witnessed any of these things.

What you have sloshing around is not liquid Helium, as this page's phase diagram shows:
http://quench-analysis.web.cern.ch/quench-analysis/phd-fs-html/node45.html
you can see that liquid stops being meaningful above 5K and helium becomes a strange not-liquid, not-gas fluid known as a supercritical fluid. I am not certain, but it is possible that a super critical fluid makes sloshy noises due to turbulence from surface interaction.

Another possibility is that in fact it is the nitrogen that has liquified - balloon gas is in fact mostly nitrogen to save money. However, looking at this page:
http://www.astro.washington.edu/larson/Astro150b/Lectures/Fundamentals/fundamentals.html
it seems that the critical point for Nitrogen is still well below room temperature.

In any case, making helium a liquid is not necessary to make it more dense than air. Hydrogen is even more convenient to work with, as metal hydrides store more hydrogen by mass than even liquid hydrogen! (and they can be safely handled)

Some poster mentioned it earlier: If you priorities is to spend youd budget on the best way to save lives then research into Cancer or AIDS isn't the best place to put it, even within the medical research field. There are other diseases that kill far more people but get far less research dollars than Cancer/AIDS already! The money goes into areas where the research companies think there will be the best return on the investment!

That said, it is a fallacy to suggest that SETI might also result in a cure for all known ills by finding the aliens who already have the cures! Again, from another poster, the best thing SETI could do is offer a wake-up call to the religiously infatuated, perhaps providing some coffee flavoured smelling salts at the same time.

FWIW, I used to run SETI, before and after BOINC. I also ran a number of other BOINC clients, including:-
SETI,
Folding,
Climate Prediction,
Einstein searching for gravitational waves,
LHC helping with the Large Hadron Collider,
Predictor trying to predict protein structure from protein sequences,
QMC,
Rosetta,
Stardust,
yada yada yada
but removed it a year or so back as it did seem to get in the way rather too often.

BOINC was just too clunky. Why did you have to register individually with each BOINC project, be given yet another HUGE number, have to search for the interesting projects yourself. BOINC should have taken care of the registration once, then offered a drop-down of active projects. Selecting something interesting would do all the install stuff for you and allow you to control the shares from the Client - currently (or at least when I left it) if you wanted to alter the share of one particular project got you had to go to each Project's website rather than just set it within the client. Just clunky!

Anyway, I moved on, but I'd have to say I'm sort of interested again and may fire up SETI again for a while to see how things have progressed since I last offered some cycles!

While the TCP/IP protocol suite was largely developed by DARPA, much of what the Internet is today (WWW) started at CERN in Switzerland.

So there.

...laura

It's a much better idea to build something like that in space, when that becomes economically viable in itself. I'm guessing that will be at least 30 years, but it could be possible within our lifetimes... With a little luck, our current energy reserves will last that long, and we won't kill ourselves waiting.

Which would require several things ... first we would need to be able to get enough material into that area of space to build something ... people answer asteroids on that one as well but you do have to smelt, refine, etc which again requires infrastructure. Maybe the moon would make more sense since at least you have a surface to work with (therefore you don't need to build that part) and some raw materials (rock) to build the parts that don't have to be some kind of metal. But then you have either to develop a relatively (laws of thermodynamics apply etc) lossless method to transmit this energy without causing more problems or produce enough energy that you don't have to care.
All of this boils down to a lot of tech we do not have and resources and energy which must be expended to reach this goal; which basically means you had better start cracking on it now to beat the deadline, like many other known problems. Of course it may just be mathematically impossible to turn what you propose into a viable solution. I'm not a physicist. I'm still not over CERN's stern ruling that the Enterprise will not exist (matter/antimatter is not viable) although it is heartening that we overcame Mr Scott and developed ion engines first. We didn't use electric cars (according to Popular Mechanics circa 1900 IIRC) because they would require such extensive infrastructure (you'd have to string wire all over the country! Electricity in every city!) so some people have been proven wrong before, but certain things are provably impossible (or not viable) without violating the Laws of Physics and Mathematics ...

Of course, there is always the desperation angle. Besides the fact Necessity is the Mother of Invention, when you get to the point where you have a choice between energy which is difficult to derive and none at all things that were too expensive before become viable economically, assuming you have a net gain of course. But solar power is way easier to deal with than this. so many processes on Earth are powered by the sun and moon that there is plenty of opportunity to reap the benefits of the "free" energy. Hopefully before we get to the point where that actually presents a problem (we use up more energy than was previously wasted or otherwise unduly interfere with natural processes necessary for our survival, or the Sun starts to grow ... ) we will have colonized somewhere else.

To my mind you started off with the right idea. You mentioned other worlds as a source. Well if people move from the Earth they can presumably find energy in the places to which they travel. Unfortunately for us, so far we only know one "earthlike" planet, where life and the possibility of life as we know it exist, and terraforming is probably much more difficult than Star Trek would have you believe... (after all if we can make inhospitable planets hospitable we should be able first to fix this one.

I was glad to hear Stephen Hawking point out that it is insane that we aren't trying to build a Disaster Recovery Site for life (i.e. extraterrestrial colonies). I've been saying that for years, but more people will listen to him for good reason. There are any number of processes which basically guarantee that life on Earth will either be destroyed or at the very least very difficult to live on, and even if that were not the case (we have no plan for basically any of them) the unforseen and the fact we know no other place where humans or any other life exists should produce a biological (to say nothing of logical) imperative to do that.

But again this requires energy, infrastructure, and technology we do not have. More people should take Einstein's advice and learn physics so they can get cracking on this stuff or help those who already are.

SPACE SCIENCE: NASA Declares No Room for Antimatter Experiment
Science 16 March 2007: 1476
DOI: 10.1126/science.315.5818.1476

News of the Week SPACE SCIENCE:
NASA Declares No Room for Antimatter Experiment
Andrew Lawler

NASA has no room on its space shuttle to launch the $1.5 billion Alpha
Magnetic Spectrometer, which is designed to search for antimatter from
its perch on the international space station.

Expanded and posted on a science blog where it was being discussed:
NASA: Alpha to Omega
Category: astro
Posted on: March 18, 2007 10:39 PM, by Steinn Sigurðsson
http://scienceblogs.com/catdynamics/2007/03/nasa_alpha_to_omega.php [scienceblogs.com]

SPACE SCIENCE: NASA Declares No Room for Antimatter Experiment

Lawler
Science 16 March 2007: 1476
DOI: 10.1126/science.315.5818.1476

News of the Week
SPACE SCIENCE:
NASA Declares No Room for Antimatter Experiment
Andrew Lawler

NASA has no room on its space shuttle to launch the $1.5 billion Alpha
Magnetic Spectrometer, which is designed to search for antimatter from
its perch on the international space station.

Hey, isn't that the Samuel Ting-Michael Salamon project?

Yes, it is:
http://ams.cern.ch/AMS/Secretariat/AmsWhosWho.html [ams.cern.ch]

NASA HQ is surely going WAY over the edge in punishing Michael Salamon. He was the head of fundamental Physics at NASA HQ, then they sent him to the White House, where he was for half a year or so the
Director of Physics at OSTP (Office of Science and Technology Policy). They pulled him out of the White House for what looks like political reasons.

This was to be the major actual Science experiment on the space station. And they are killing it -- why? I am leaning towards thinking that it is a purely political decision, as the "room" or money
argument is unconvincing, and as I say, it seems to be the #1 science project in the entire Space Station program.

If one detects even a single anti-carbon nucleus, one almost has to conclude that someplace there is an anti-star performinbg anti-nucleosyntheis, which exploded asn anti-supernova.

What a huge discovery that would be by the Alpha Magnetic Spectrometer. For that tremendous science value per dollar ratio alone, it should fly.

I am going to write to my congressman and senators. Maybe it would be worth writing to, say, Oprah. The tax-paying public deserves to have SOME science done with their NASA tax dollars.
====

Yep, I'd like to see it launched, too. Cancelling an experiment after spending 1.5 billion to build it is just the sort of idiocy that the govenment does all the time, though.

If you follow NASA politics, though, you'd see that there's no reason to invoke any sort of "punishment" to understand this call. Griffin was given the order to cancel space shuttle by 2010. When you add up
all the things that Griffin has been instructed to do with the shuttle before the drop-dead do-not-fly-it-any-more date, and look at the maximum flight rate that's considered to be safe, there are zero flights available.

Of course, adding one more shuttle flight in 2011 would make perfect
sense-- the replacement for the shuttle won't be available for
another four years, so why not? But at the moment, that is being
considered the "camel's nose under the tent" thinking, and "cancel
shuttle by 2010" is a non-negotiable deadline.
- Show quoted text -

From the same blog and thread, a reply about Michael Salamon and the
Alpha Magnetic Spectrometer:

==========

He was the head of fundamental Physics at NASA HQ, then they sent him
to the White House, where he was for half a year or so the Director of
Physics at OSTP (Office of Science and Technology Policy). They pulled
him out of the White House for what looks like political reasons.

I thought that the device NASA might leave behind was the AMS, which doesn't look habitable

As a side note, I almost wet my pants seeing that Fortran is finally dead and buried.

PHYSICS NEWS UPDATE

The American Institute of Physics Bulletin of Physics News

Number 841 October 2, 2007 by Phillip F. Schewe www.aip.org/pnu

THE VACUUM STRIKES BACK. Modern physics has shown that the vacuum, previously thought of as a state of total nothingness, is really a seething background of virtual particles springing in and out of existence until they can seize enough energy to materialize as *real* particles. In high energy collisions at accelerator labs, some of the original beam energy can be consumed by ripping particle-antiparticle pairs out of the vacuum. Sometimes this process is the very reason for doing the experiment, but sometimes it is only a detriment. For example, in the Large Hadron Collider (LHC), under construction at the CERN lab in Geneva, a major source of beam losses (particles exiting from the usable beam) for heavy-ion collisions is expected to be a class of event in which the counter-moving ions pass each other and don*t interact except to spawn a pair of particles---an electron and positron---one of which (the positron) goes off to oblivion while the other (the electron) latches onto one of the ions. This ion, bearing an extra electric charge, will now behave slightly differently as it races through the chain of powerful magnets that normally steer the particles around the accelerator. Going a certain distance, the modified ion will leave its fellows and smash into the beam pipe carrying the beams, thus heating up the pipe and surrounding magnet coils.

Fearing these future beam losses, accelerator physicists have sought to observe this effect at an existing machine, the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven Lab on Long Island. And they found what they were looking for, a tiny splash of energy amounting to about .0002 watts, or about what a firefly puts out. The RHIC beam for these tests consisted of copper ions each carrying 6.3 TeV of energy (about 100 GeV per nucleon). According to CERN scientist John Jowett (john.jowett@cern.ch, 41-22-7676-643) this troublesome class of events, referred to as bound-free-pair production (or BFPP, the bound referring to the electron and the free to the positron), will be much more formidable at LHC than at RHIC. First of all, the pair production scales as the atomic number of the nucleus (or the charge of the nucleus, denoted by the letter Z) raised to the seventh power. The LHC heavy-ion collisions will use beams composed of lead ions. The more highly charged nucleus and the larger energies (574 TeV per lead nucleus) mean the BFPP process should be some 100,000 times more prominent than in the test at RHIC. This would amount to about 25 watts, the equivalent of a reading lamp. That doesn't sound like much but, when deposited in the ultra-cold (1.9 K) magnets of the LHC, it could bring them to the brink of "quenching" out of their superconducting state, interrupting the operation of the huge machine. (Bruce et al., Physical Review Letters, 5 October 2007; journalists can obtain the text from www.aip.org/physnews/select; other background material at arxiv.org/abs/0706.3356v2), http://cern.ch/AccelConf/e04/PAPERS/MOPLT020.PDF, Vol. I, Chapter 21 of the LHC Design Report, available at http://

PHYSICS NEWS UPDATE

The American Institute of Physics Bulletin of Physics News

Number 841 October 2, 2007 by Phillip F. Schewe www.aip.org/pnu

THE VACUUM STRIKES BACK. Modern physics has shown that the vacuum, previously thought of as a state of total nothingness, is really a seething background of virtual particles springing in and out of existence until they can seize enough energy to materialize as *real* particles. In high energy collisions at accelerator labs, some of the original beam energy can be consumed by ripping particle-antiparticle pairs out of the vacuum. Sometimes this process is the very reason for doing the experiment, but sometimes it is only a detriment. For example, in the Large Hadron Collider (LHC), under construction at the CERN lab in Geneva, a major source of beam losses (particles exiting from the usable beam) for heavy-ion collisions is expected to be a class of event in which the counter-moving ions pass each other and don*t interact except to spawn a pair of particles---an electron and positron---one of which (the positron) goes off to oblivion while the other (the electron) latches onto one of the ions. This ion, bearing an extra electric charge, will now behave slightly differently as it races through the chain of powerful magnets that normally steer the particles around the accelerator. Going a certain distance, the modified ion will leave its fellows and smash into the beam pipe carrying the beams, thus heating up the pipe and surrounding magnet coils.

Fearing these future beam losses, accelerator physicists have sought to observe this effect at an existing machine, the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven Lab on Long Island. And they found what they were looking for, a tiny splash of energy amounting to about .0002 watts, or about what a firefly puts out. The RHIC beam for these tests consisted of copper ions each carrying 6.3 TeV of energy (about 100 GeV per nucleon). According to CERN scientist John Jowett (john.jowett@cern.ch, 41-22-7676-643) this troublesome class of events, referred to as bound-free-pair production (or BFPP, the bound referring to the electron and the free to the positron), will be much more formidable at LHC than at RHIC. First of all, the pair production scales as the atomic number of the nucleus (or the charge of the nucleus, denoted by the letter Z) raised to the seventh power. The LHC heavy-ion collisions will use beams composed of lead ions. The more highly charged nucleus and the larger energies (574 TeV per lead nucleus) mean the BFPP process should be some 100,000 times more prominent than in the test at RHIC. This would amount to about 25 watts, the equivalent of a reading lamp. That doesn't sound like much but, when deposited in the ultra-cold (1.9 K) magnets of the LHC, it could bring them to the brink of "quenching" out of their superconducting state, interrupting the operation of the huge machine. (Bruce et al., Physical Review Letters, 5 October 2007; journalists can obtain the text from www.aip.org/physnews/select; other background material at arxiv.org/abs/0706.3356v2), http://cern.ch/AccelConf/e04/PAPERS/MOPLT020.PDF, Vol. I, Chapter 21 of the LHC Design Report, available at http://

Seriously, does this still need to be repeated? The web was invented at CERN, a European nuclear physics research facility.

The CMS detector will take data at 8GB/s at turn on (that's gigabytes, not gigabits). This will be filtered and a few percent will be saved.

CASTOR's (the CERN data store) current stats are here:

http://castor.web.cern.ch/castor/

About 8 PB of files. If i recall correctly, there's around 500TB of online disk space and 10-30PB of tape storage (some of it is getting phased out).

FNAL has a similar setup, except with a storage manager called dCache. There is no use of protocols like iSCSI or Fiber Channel over IP, but rather physics-specific ones (xrootd, rfio, dcap) and grid-specific ones (SRM and gridFTP).

Well, don't know about the storage capacity, but the LHC will produce around 15 petabytes per year, when they turn it on.

That is to say: http://root.cern.ch/

Of course the fa that I was referring to is here. Much more informative than AC's post if I may say...

http://public.web.cern.ch/Public/Content/Chapters/ AboutCERN/CERNFuture/WhatLHC/WhatLHC-en.html

Soon the universe will be ours, my friend, soon.

I'm not sure if this will meet your needs, but when I did my high energy physics Ph.D. dissertation work at the D0 experiment at Fermilab we mainly used PAW http://paw.web.cern.ch/paw/ for our analysis/visualization IIRC. It is, I think, freely downloadable for multiple platforms and worked quite nicely for me back in 1988-1996. I've been out of the HEP field since so I haven't followed its development, but since it's still available, my guess is it's even more powerful now, although as I said, I'm not sure if it will meet your needs. Hope this helps and good luck.

The folks at CERN maintain a set of libraries for analyzing nuclear and high-energy physics data sets, known as 'root'. These also include the Parallel ROOT Processing Facility, or PROOF. I'm guessing that PROOF will play an important role in the analysis of this experiment once it comes online.

I have never heard another physicist refer to it as the god particle (except when satirising media articles on the subject). It is an unfortunate expression and I don't like it.

The Higgs boson is an important part of a theory called the Standard Model, our best theory of the interactions of fundamental particles. It is the last fundamental particle in this theory left to be discovered and is an integral part of it. Looking for the Higgs is about understanding nature at its most fundamental level and I think that makes it worthwhile. The LHC is aiming to find or disprove the existence of the Higgs and explore other new physics. There is also a huge amount of spin out technology which comes from it which is also useful (although I am far less interested in that). If you are interested in what the LHC is for have a look at CERN's FAQ or wikipedia .

The data analysis for the LHC experiments uses the LHC Computing Grid . The analysis is spread out between different sites (exactly what happens at which sites depends on the experiment). The PCs which make up the grid though are largely (fom what I have seen) Dell PCs.

Data analysis for particle physics is highly parallelisable (large number of events, on which you want to run the same analysis) so large numbers of inexpensive computers makes more sense than super computers.

Not only did the Slashdot editor not catch a spelling mistake, he apparently didn't catch the fact that the linked article is an advertisement from CXO Media, which, according to its web site, mixes articles and advertisements: "Through our integrated media and marketing programs we provide..."

From the linked article: "... the team is using Quantum's StorNext software as its file system..."

Question: Did a Slashdot editor get paid directly for running an advertisement disguised as an article? Or was someone in Slashdot's parent company paid "under the table"? Or did the parent company get paid?

Anyone wanting to read a real article from 2005 about CERN's data handling, data storage, and data processing can download this PDF file: Grid Computing: The European Data Grid Project.

Real articles begin this way: "The computing challenges for LHC are: * the massive computational capacity required for analysis of the data and * the volume of data to be processed."

Advertisements begin by talking about God and murder, this way (from the article linked by Slashdot): "CERN's Search for God (Particles)..."

and "Maybe you last read about CERN (the European Organization for Nuclear Research) and its massive particle accelerators in Angels & Demons by Dan Brown of The Da Vinci Code fame. In that book, the lead character travels to the cavernous research institute on the border of France and Switzerland to help investigate a murder."

Initially some data is being filtered at the detector pits by the farms of PCs doing the triggering. After that the data will be fed to storage and analysis. CERN has been upgrading its computer centre for quite some while (the main problem is not power supply, but cooling system - thus some of performance benchmarks also include it). Besides CERN (Tier-0) will have high-speed connections (via means of LCG backbone) with many sites around the world and the data processing will be done in a 'global manner'.

You can google on phrase 'service challenge' site:cern.ch, or just go to the LCG site.

--
Milosz

I agree with you. RMS has made his position clear several times over. He gave a talk at CERN a few weeks ago. A video of his talk *used* to be available in the free ogg format through this site. But then someone probably high up in IT, objected evidently, and they sent off an e-mail to RMS, asking him to approve that it should also be released in the CERN-IT approved standard formats. Now, I dont know what that format is, but I am guessing that it is proprietary! And so, I doubt RMS will ever approve it... Anyways, back to the point... I was there for his talk and also downloaded the ogg back when it was available and here is a short transcript of what he had to say about Torvalds. After insisting that GNU be included in the name of the distribution to give credit to the free software developers and to avoid confusion, he said "This confusion led people to think that the whole system was Mr. Torvald's work and [..] think that the whole system came from his vision of the world." And continued with...

"Torvalds does not support the ideas of freedom that I have been telling you about. He never did. [..] He calls himself apolitical which refers to the political position that we should make important political decisions according to short term practical convinience. He says he values powerful reliable software and that's all. He is against the idea that all users should have freedom and he has demonstrated this by conspicious involvement with non-free software. Ten years ago, he worked for a company in which his job was to develop non-free software. Five years ago, he used a non-free program in a very public way for the development of Linux which sent the wrong message to the community and I criticised him for that. Well, he has the right to his views. [..] What I object to is that people think that our work was done by him and when our work serves as the platform for him to state his views and to drown us out. And that's what happens if you call the system Linux. It's not fair to do that because it means you are failing to give us credit for our work. [..] So please call the system GNU/Linux or GNU+Linux. [..] But, there is something more important at stake and that's called freedom. There are people who would like to take away your freedom. The only way to keep your freedom is if you are prepared to defend it. "

I appreciate your feedback and am not disputing what you said. I find it interesting to hear how linking to another page is bad considering what the inventor of the World Wide Web had to say about hyperlinking. I guess that it is a zero sum game when battling for position in your google rank.

Thanks, again, for your feedback.

It works fine, but we actually tend to lean toward many streams as opposed to uber-fast single streams.

Truthfully, you have to tweak the system pretty hard to get decent performance over a single stream (for us, 155 Mbps isn't sufficient - I work on a LHC project), especially from Nebraska to Switzerland (CERN). FAST TCP helps out a whole lot. GridFTP is the other piece of the equation - it is basically FTP with multiple data streams.

We tend to lean on hundreds of streams a whole lot more than tweaking TCP settings, and the Caltech guys give us heck for that. They're right, however - if you're getting 100s of KBps per stream to some European site, it just takes a ridiculous number of streams to get up to 100 MBps. Right now, the storage systems are behind the network, so we haven't even been able to start playing with FAST TCP yet.

http://cmsdoc.cern.ch/cms/aprom/phedex/prod/Activi ty::RatePlots?graph=quantity&entity=dest&src_filte r=&dest_filter=Nebraska&no_mss=true&period=l14d&up to=&.submit=Update

Yup,

http://cmsdoc.cern.ch/cms/aprom/phedex/prod/Activi ty::RatePlots?graph=quantity&entity=dest&src_filte r=&dest_filter=Nebraska&no_mss=true&period=l14d&up to=&.submit=Update

In fact, we often talk with the Caltech folk about deploying FAST TCP; the problem is that both ends need to deploy the kernel patches. Truthfully, the limiting factor becomes the disk systems, not the network. When we start to push closer to 10 Gbps instead of 4-6 Gbps, we'll need to make smarter decisions about the TCP stacks.

Let's start with a Slashdotting of NASA...

• Scalable Dynamic Chimera Methods for Unsteady Aerodynamics is one of those packages mere mortals like us will have either no use for or will have to just drool over.
• Fully Unstructured Navier-Stokes 3D is a nice Fortran-based CFD, requires some hefty paperwork to obtain, and may need you to use G95 rather than GCC's GFortran, due to compiler bugs.
• OVERFLOW and related CFD software.
• Three Dimensional Multi-block Advanced Grid Generation System is the component that actually lets you do a lot of the necessary grid work for CFDs.
• Viscous Upwind ALgorithm for Complex Flow ANalysis is the hardest of the CFD codes at NASA to obtain, but if you want to work on anything hypersonic, it's the best place to start. Do Not Use hypersonic airflows for CPU cooling.

• Astrophysical Thermonuclear Flash Simulator - well, you never know.
• Geant4, for the subatomic nuclear physicist in your life...
• Open Field Operation and Manipulation is a nice open-source CFD package.
• Parallel Basic Local Alignment Search Tool gives you a parallelized search engine for nucleotides and proteins.
• Stanford Exploration Project provides some nice parallel geophysics applications and tools.
• Tachyon Parallel Raytracer is a nice example of what you can do with parallelism and graphics.

• Kerrighed is an up-and-coming clustering system for Linux. I saw it demonstrated at SC|05 - and was less than impressed. It needed a lot of work at that point. However, it looks like it has improved a lot since then, and it would be unreasonable to not mention it.
• MOSIX is the second-oldest clustering technology to gain a fan following to rival Star Trek. It's very good, though hard to get if you're not in academia. Arguably for entirely fair reasons.
• OpenMOSIX was originally a fork from MOSIX but is now essentially its own clustering technology. Development is nowhere near the speed I'd like, it does need far more eyes, but is well-known and highly regarded. Moshe Bar is also one of the coolest developers I've encountered.

• DAKOTA is a program for profiling parallel applications and should be useful in telling you where you are gaining and losing.
• HPC Toolkit is another toolkit for profiling HPC applications.
• is yet another profiler for parallel software. Between this and the others I've listed, you should have more information than sequential programmers ever get to work with.
• Performance API is a facility used by most of the profiling software to provide an architecture-independent view of performance counters. I have it on good authority that some (now former)

Well, the US has got several valuable neutrino projects, which often gets overlooked. Don't forget LIGO... Also, the US has a lot of potential for doing science (particularly particle physics) in space, which is a boat that it is missing by stopping the shuttle program and concentrating on Mars... which is sad... Big science is hard to fund, when the administration is this ignorant. But still, there are lots of small, cute particle physics experiments cropping up everywhere, from dark matter detection to measurement of "G" and those dont require as high budgets, so there is still hope!! I am worried about the ILC, however...

If you are physics undergrad at a US university, I highly recommend the CERN summer student program. You can probably get NSF or DOE to fund you. It is totally worth applying to, although the chances of getting in are slim. To be at CERN when the LHC starts up next summer, is an experience worth fighting for! And really, I would not worry about finding work if I were you... If you already know what ITER is, you are in good shape.

Ok, so this is off topic, but might be interesting to those curious about what's happening at CERN.

Allan Cameron and Ron Howard was at CERN last week. Here is a photo.

Tom Hanks will be here in two weeks to visit the LHC and in the fall, Angels and Deamons will be filmed at CERN... Why the hurry? It has only been two months since the cast has been selected?! Presumably, they want to shoot before the LHC closure sometime in March... ?

Storing all the data is also a problem. Both of the detectors' data models are larger now than previously thought. This increases the requirements on storage and also the computing power necessary. Not only that, but the computing centers have not ramped up as fast as we thought they would... May sounds like a reasonable time scale to solve both of these problems.

Shortly after the birth of the Universe in the Big Bang, as the universe expanded the temperature fell below a critical value where a new type of field developed everywhere in the Universe (field, cmp. magnetic field around a magnet. Every point in space has a property: a measurable magnetic force and direction). We call this particular field the Higgs field. Some particles coupled to this field and the property they acquired is what we measure as mass. That is, particles are not solid in themselves but can be seen as a wave on a water surface. Although a wave moves no water from one side of a lake to another, it carries a lot of information: energy, momentum, amplitude, wavelength, etc. For particles mass is just another property acquired by interacting with the ever pervading Higgs field and that property we perceive as mass.

It's too bad the US isn't building a National Ignition Facility to produce fusion in the laboratory using the largest lasers on the planet.

If only there were physicists scrutinizing the data produced by something like Gravity Probe B here in the US.

Something like a Z Machine would be really useful for high energy physics, but the fundies in the US won't allow it.

Then there is NASA, sitting its laurels of times long past, not making any effort to replace [1] the ill-conceived shuttle.

The US isn't attempting to measure the rate of polar ice cap melting using precise measurements of the exact center of mass of the entire planet. No, because physics in the US sucks and that sort of work is best left to others.

If the NSF wasn't completely dominated by neo-cons it might have funded Kip Thorne and let him build the most sensitive laser interferometer on Earth.

There aren't a dozen people orbiting the planet attempting to assemble the largest space based solar collector in history; the physics involved are far beyond anything practiced in the US. I can just imagine Americans in space, risking life and limb. They'd probably find themselves using staple guns to keep from getting killed on live TV. The US is too cowardly for any of that.

If Europe had only had the wisdom to exclude the US from LHC, Fermilab's mistakes wouldn't have led to their current magnet problems. There's the US again, setting back physics by another decade.

Then there are the beef-eaters in Detroit, oblivious to any concept that doesn't involve guzzling gas.

Those damn Christens did manage to stifle US fusion research; the next big Tokamak is being built in France for crying-out-loud. There's hardly even any US funding involved.

That article is right. The US is nothing but a swill of gun-toting suburbanite consumers, polluting and terrorizing the world.

[1] Watch the quarterly report video on the right panel; bunch of silly US bubba cowboys trying to engineer a rocket. What a laugh.

Being a CMS researcher I guess you have already heard about http://monalisa.cern.ch/FDT/ that was especially developed for this purpose (high speed transfer over paths with large RTT). It goes to the maximum possible transfer rate in a matter of seconds and can pipe multiple files through the same channel especially to avoid situations like you describe.

Thanks for the link to http://lhc.web.cern.ch/lhc/general/acphys.htm. The Outreach area at http://lhc-machine-outreach.web.cern.ch/lhc-machin e-outreach was also a good read.

Hard UV photons impinging on the beampipe due to synchrotron radiation for the entire length of the beampipe! We mostly cared about synchrotron radiation near the ion source (highest potential area of the system). Of course, it was named synchrotron radiation for a reason, but it was never something I had to be concerned about in terms of system sensitivity, *throughout the system*. We created a lot of electrons when the beam struck photoresist (think baked-on goo) on the target silicon wafers. So at higher energies, it was factor.

And of course this was an industrial vacuum system, with a dirty ion source, usually a dirty target as well, and graphite liners in critical places such as the outer wall of the beampipe in the magnetic analysis area. Not an easy environment for developing a good vacuum. After a vent to atmosphere, we would usually pump the systems down to the low E-7 Torr range, but operating pressure was higher, throughout the system.

If I'd first read that LHC was operating in the E-10T range, I'd never have asked about an aluminum beampipe. That was a silly question, as it's simply not a suitable material for those ranges due to microscopic granularity. Nor have I ever heard of an aluminum bellows. Again, simply not a suitable material, because of both granularity and flexibility characteristics (they would develop pin-hole leaks very rapidly).

BTW, It's been some time since I worked in that industry. During one of the periodic downturns the industry was famous for, I migrated to computing. So this is a 'blast from my past', a look at where the technology has gone, and a look at where some fundamental new science will be coming from. Interesting on several levels, in other words, and thanks for your posts.

I suspect that following LHC technology and results will continue to be very interesting, even from my almost-completely lay perspective.

Thanks for the link to http://lhc.web.cern.ch/lhc/general/acphys.htm. The Outreach area at http://lhc-machine-outreach.web.cern.ch/lhc-machin e-outreach was also a good read.

Hard UV photons impinging on the beampipe due to synchrotron radiation for the entire length of the beampipe! We mostly cared about synchrotron radiation near the ion source (highest potential area of the system). Of course, it was named synchrotron radiation for a reason, but it was never something I had to be concerned about in terms of system sensitivity, *throughout the system*. We created a lot of electrons when the beam struck photoresist (think baked-on goo) on the target silicon wafers. So at higher energies, it was factor.

And of course this was an industrial vacuum system, with a dirty ion source, usually a dirty target as well, and graphite liners in critical places such as the outer wall of the beampipe in the magnetic analysis area. Not an easy environment for developing a good vacuum. After a vent to atmosphere, we would usually pump the systems down to the low E-7 Torr range, but operating pressure was higher, throughout the system.

If I'd first read that LHC was operating in the E-10T range, I'd never have asked about an aluminum beampipe. That was a silly question, as it's simply not a suitable material for those ranges due to microscopic granularity. Nor have I ever heard of an aluminum bellows. Again, simply not a suitable material, because of both granularity and flexibility characteristics (they would develop pin-hole leaks very rapidly).

BTW, It's been some time since I worked in that industry. During one of the periodic downturns the industry was famous for, I migrated to computing. So this is a 'blast from my past', a look at where the technology has gone, and a look at where some fundamental new science will be coming from. Interesting on several levels, in other words, and thanks for your posts.

I suspect that following LHC technology and results will continue to be very interesting, even from my almost-completely lay perspective.

Here is a very good article which details the challenges in building the LHC: link.

The beampipe is stainless and not aluminum. The most important reason is the bellows which connect different sections of the beampipe and allow for the rather substantial contraction of the beampipe when it goes from room temperature to 2K. I can not find the figures right now, but if my memory serves me right, it was on the order of 10m over the whole 27km. Such bellows can not be made of aluminum, I am told. Stainless does not outgas and hold vacuum well and also makes better welds. It is, however, awful in a radiation environment as it does activate! The experiments use berylium for the interaction regions, to keep the radiation length to a minimum, but use that for a few meters only, as it costs too much. 40meter berylium pipe, I am told, costs 40 million SFr. So people here are looking into using aluminum for 20m on both sides of the 2-3m berylium pipe in the experiments. (Note, the active length of ATLAS and CMS are like 40 meters.)

And the answer is yes, we are baking out kilometers of beamline! Meaning, heating it up to get rid of all the "muck" that is stuck inside the vacuum pipes to make sure we get rid of it before we put the beam in there. Noone around here on my floor knows how we do it actually, but everyone is pretty sure that we do...

Btw, I am a detector physicist. Not an accelarator physicist. But yes, well, we have to know quite a bit about the LHC to be able to use it! :)

Incidentally, since you work on silicon technology, it might interest you that the detectors closest to the interaction point (or collisions) are all made of silicon. In ATLAS's case there is 68m^2s of it and in CMS, it is about 120m^2s of it in total. That might sound like a lot of silicon, but it is about two buckets of sand since it is about 300 microns thick... Except, it costs a lot of money... and generates 200million bits of data at each collision and collisions are at 40MHz so the data rate is pretty damn high. (No, we dont read all of it. We cant... We read out only the interesting events at 75kHz.)

The beam parameters for the LHC beam are listed here and yes, it is an impressive list. The experiments at IP1 and IP5, which are respectively ATLAS and CMS are listed as having a beam spot of 16.7 while the other two (ALICE and LHC-b) will have a beam spot of 70.9 as they do not need as high luminosities to achieve their perspective goals.

The beam size around the ring remains largish ~ 100 to 200 microns mostly, but then the beams are squeezed just before the collisions on both sides of the experiments. This "squeezing appraratus" happens to consist of three sets of quadrapole magnets. Incidentally, these magnets are holding up the LHC schedule as one of them failed a test.

I do not know what the beampipe is made of, but I would guess stainless steel. (Will check with machine people today.) (The beampipe itself is housed in a stainless steel casing with lots of services inside it.) The beampipe inside the experiments are made from berylium as it has be a material which has very small radiation length to avoid particles coming out of the collision interacting with it too much.

I do not know much about space charge issues but I do know that the circulating beam current is 0.582 A, and so carries a beam halo of other particles with it and wake field calculations are hard...

Yes, and they set up they're own computer clusters to sift the data looking for these signatures. Just take the search comment as the joke it was and leave it at that.

One thing the article doesn't mention is that the CERN already pushes incredible amounts of data accross large distances. From their facts page:

Fact 24) On 1st October 2003 CERN and the California Institute of Technology set a new Internet Land Speed Record by transferring 1.1 terabytes of data in less than 30 minutes across 7000km of network. The equivalent of transferring a full length DVD movie in 7 seconds.

Another thing they don't mention is how much data is being thrown out at the source. Collisions will occur in the LHC at 40 MHz. A trigger will only record data from those events that "look right," which cuts that down to about 100 Hz. That right there is a 99.99975% reduction in data.

And of course, none of the research sites are going to want all of the data.

That's not "High Productivity Computing" Wire... the HPC in "HPC Wire" stands for High-Performance Computing.

The real story on the ~15PB/year data store is to be found in these two sites:

This outlines the hardware environment supporting the data (IBM 3584 w/ Ultrium and IBM DS4400):
ftp://ftp.software.ibm.com/common/ssi/rep_sp/n/GRC 03001USEN/GRC03001USEN.PDF

This outlines the software environment (layered Tivoli Storage Manager and dCache):
http://www.dcache.org/manuals/tsm-symposium-2005-p aper.pdf

Or is it?
Here, Sun posts how Storagetek supplied the tape storage:
http://www.sun.com/customers/storage/cern.xml

The LCG
Something could certainly be said about their computing backend of going through this data. It's called the LHC LCG (Large Hadron Collider Large Computing Grid) and is described here:
http://lcg.web.cern.ch/LCG/tdr/LCG_TDR_v1_04.pdf

That's 4Gbps AVERAGE, meaning it's much below the peak rate. That's also the raw data stream, not accounting for site X in the US wanting to read reconstructed data from site Y in Europe.

LHC-related experiments will eventually have 70 Gbps of private fibers across the atlantic (Most NY -> Geneva, but at least 10Gbps NY -> Amsterdam), and at least 10 Gbps across the Pacific.

For what it's worth, here's the current transfer rates for one LHC experiment You'll notice that there's one site, Nebraska (my site), which averages 3.2 Gbps over the last day. That's a Tier 2 site - meaning it won't even recieve the raw data, just reconstructed data.

Our peak is designed to be 200TB / week (2.6Gbps averaged over a whole week). That's one site out of 30 Tier 2 sites and 7 Tier 1 sites (each Tier 1 should be about 4-times as big as a Tier 2).

Of course, the network backbone work has been progressing for years. It's to the point where Abilene, the current I2 network, rarely is at 50% capacity.

The network part is easy; it's a function of buying the right equipment and hiring smart people. The extremely hard part is putting disk servers in place that can handle the load. When we went from OC-12 (622 Mbps) to OC-192 (~10Gbps), we had RAIDs crash because we wrote at 2Gbps on some servers for days at a time. Try building up such a system without the budget to buy high-end Fiber Channel equipment too!

And yes, I am on a development team that works to provide data transfer services for the CMS experiment.

The solution is "The Grid", a parallel network used to transmit and process data to/from the seven processing and archiving stations around the world Here's how it works: http://gridcafe.web.cern.ch/gridcafe/index.html

http://doc.cern.ch/yellowrep/2003/2003-001/p1.pdf
This paper concludes that there's "no basis for any conceivable threat" from microscopic black holes and other suggested dangers.

> Yep. And the documentation at CERN is done using TeX :-) http://twiki.cern.ch/ Doesn't look like TeX ;)...

Actually, a lot of new technologies that have immediate applications in your daily life had to be invented.
For instance, the CERN Openlab http://proj-openlab-datagrid-public.web.cern.ch/pr oj-openlab-datagrid-public/ develops new networking, storage and parallel computing technologies that will help us deal with the incredible quantity of data that will be generated by the LHC experiments.
Along the same line, new tomographic methods will revolutionize the way we treat cancers and leverage medical imagery. http://bulletin.cern.ch/fre/articles.php?bullno=04 /2005&base=tra

So no, it's true, if you're part of a CERN member state, it wasn't what you paid for with your hard earned tax money. It's like a big chocolate box, it's be a shame to throw it all away just because you don't like almonds right ?