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It's pretty esoteric, but I've been using the Python interface to the ROOT particle physics framework for all my plotting needs.

It has a bunch of specialised features that appeal to physicists, not least the brain-dead histogramming. I do find the whole framewok poorly documented in general, and wouldn't recommend it to the general numerical computation public.

However, I think this demonstrates the great thing about using a general purpose language like Python for numerical work. You can really use tons of different libraries and frameworks together. I use ROOT almost exclusively, since it enables me to talk in th esame terms as my colleagues. The power lies in being able to add in network or gui or input code written in python and any number of available libraries.

And naturally, in such speciallised fields, YMMV.

Maybe what you look for is already solved by high energy phycisists: The ROOT toolkit is at least supposed to handle very large datasets (I never tried that, though).

But in the end: THEORY. Because I can't feel atoms or sub-atomic particles

Sure you can.

Lick your fingers, then with the same hand grab a fork and stick it in the nearest electrical socket. You'll be feeling all sorts of sub-atomic particles.

But seriously, you don't consider bubble chamber photos or electron microscope photos of atoms as conclusive enough, albeit vicarious, touching of atoms and sub-atomic particles to dispense with some of the caveating about atomic theory?

I understand exactly what SCADA is. I was wondering if you are using it for local or remote network control. The extent of my SCADA experience has been interfacing with PLCs in large manufacturing and power generation.

For those looking to find out more about SCADA and/or OPC, you might want to have a look at the SCADA Working Group webpage or primers such as this one.

http://root.cern.ch/
Not quite the simplest program, but it can do what you want, is for free and available for a lot of platforms.
T

The statement "The biggest collider" is not correct, a simmilar installation, but by ways larger is the CERN in Genf (Switzerland). The LHC (Large Hadron Collider) measures about 7 Kilometers, or 4.34 Miles in Circumference. According to the CERN Website, a new gigantic collider is planned, that will measure incomprehensable 49 Kilometers in circumference. Another new hadron collider is the TESLA Installation in Hamburg (Germany). It will be a Tandem linear Collider, with it's origin in the DESY complex, wich is a pretty large Research installation itself, check their Website.

The statement "The biggest collider" is not correct, a simmilar installation, but by ways larger is the CERN in Genf (Switzerland). The LHC (Large Hadron Collider) measures about 7 Kilometers, or 4.34 Miles in Circumference. According to the CERN Website, a new gigantic collider is planned, that will measure incomprehensable 49 Kilometers in circumference. Another new hadron collider is the TESLA Installation in Hamburg (Germany). It will be a Tandem linear Collider, with it's origin in the DESY complex, wich is a pretty large Research installation itself, check their Website.

bastardizing a research network

Yeah right. Aside from using it to test some pretty fancy high speed protocols, the Internet2 in general is really nothing more than a fast pipe for college students to download music on, insulated from the original Internet by BGP. You never see an academic conference requiring "tests on the Internet2" because its geographic concentration is entirely in North America and its speed is totally beyond anything you see in the real Internet; that is why everyone wants PlanetLab instead.

- sm

Despite ever increasing demand for bandwidth the cost of network traffic has only gone down over the past decade. There is nothing to suggest this trend will not continue into the foreseeable future. So in so far as spam is a real problem it doesn't seem to affect what is arguably the most important metric here, namely end user cost.

From one kind of economic perspective, yes, it might make sense to differentiate between network services and users, and to mandate elaborate tariff structures, authorization mechanisms, etc. But it is just as likely to lead to the creation of cartels and innovative sclerosis: witness the slow uptake of multimedia services in the mobile phone market, which are widely recognized as too expensive and lacking in interoperability.

The Internet is a dumb network which solves problems by brute force. It is exactly this property which caused it to win out over smarter networks such as Minitel or the various X.25 implementations. (a fairly comprehensive account of this development is given in the following web lecture by Paul Kunz)

But since the Internet is dumb, there's nothing stopping you from offering a prepaid email service. If spam is really as big a problem as you make it out to be then people will flock to your service. But I don't think they will.

The people at the Tier 1 LHC computing center GridKA in germany are already using a water-cooled components. from: http://lcg.web.cern.ch/LCG/peb/MoU/IWR-Rep-GridKa0 022-v1%201-LCGPlanningPhaseII-160704.htm "GridKa developed an efficient, modular cooling concept based on closed water-cooled cabinets. ..."

Because the speed of light is constant and matter cannot exceed the speed of light. No amount of continuous force applied to matter can ever allow the matter to exceed the speed of light. The energy required to accelerate matter to the speed of light is infinite. That's why particle accelerators like CERN can never actually test collisions of particles at light-speed. Only at near light-speed.

Black holes and high speed matter are all part of Einstein's relativity. Read up on that to understand black holes better.

On the LHC project, One person's 3.4ghz does 1.4 gigaflops. but that's per cpu in a dual cpu machine. http://lhcathome.cern.ch/show_host_detail.php?host id=27742

... inconsistent with the recent data from the Large Hardon Collider? Could anyone explain that expanding/shrinking phenomenon in lay terms please?

Now, the LHC (Large Hadron Collider), that's a different story. Here the energy density and black hole production cross sections are actually high enough, a black hole production signal could actually be measured.

Sadly, in all cases, the black holes evaporate harmlessly.

1) The energies of the protons hitting the top of the atmosphere are very very high. The muons themselves at the ground have energies of a few GeV, and they themselves have lost 2 GeV just getting down through the atmosphere. The primary particles (mostly protons) creating the detectable ground-level showers have energies from tens of GeV's on up (TeV's, PeV's, etc.) The fluxes of these particles drop off as a power law with energy.

Incidentially, the highest energy cosmic ray detected was over 10^20 eV! I believe the flux for particles at that energy are something like one event per square kilometer per century or something like that.

2) Muons are leptons, so they are not affected by the strong force, as you mention.

For charged particles another source of energy loss is through radiation as they accelerate (or decelerate). When a charged particle passes close to a nucleus it can have its trajectory altered resulting in radiation emission. This is bremsstrahlung. If the radiated photons have enough energy (greater than 1.02 MeV), they can pair produce into electron/postitrons and thus an electromagnetic cascade is born. It turns out that the energy radiated has a 1/m^2 dependence, which makes it very important for electrons, but basically nothing else (the muon being 207 times the mass of the electron, I believe). This is why muons don't create showers, or conversely why basically only electrons and photons do.

Because charged muons don't strongly interact, and they don't create showers, their dominant energy loss mechanism is due to ionization and atomic excitation (because they have charge), which is well described by the Bethe-Bloch equation.

Hadronic showers, by the way, are a little bit tricky because the shower profile and composition fluctuates so much (electromagnetic showers are very well behaved and easy to identify). To design them you need to take care to put an electromagnetic calorimeter in front of them so you can tell the difference between electromagnetic and hadronic showers. The material that makes up the EM part has to be something that will ensure a good EM shower, but with low enough Z so that the hadrons will not start their shower there. Occasionally hadrons will knock off an electron in the EM part, which will cause a EM shower and make it look like a EM event, but this is just part of the background that you need to take statistically into account by making good computer models (along with other things like getting a handle on how what percentage of hadrons at a given energy will be entirely contained in the calorimeter and what will leak out the back). You can't construct and analyze a particle detector these days without a very good physical model of it.

Muons are the most dominant charged particle in terms of flux on the ground not because they they can travel longer through the atmosphere, but because when a high-energy primary proton comes barrelling through the atmosphere it knocks off lots of pions in the downward direction that then decay into high energy muons. For every one proton that initiates such a particle shower, you get many many muons.

At least they have been shown to slightly disturb experiments at the CERN accelator ring.

At a certain load level their web server traffic is routed into an enormous proton accelerator where all the requests go into an infinite loop until they collide and create odd shapes

What is LHC.

We actually had an enlightening visit to CERN with our physics-professor with explanations done by the chief-engineer (was luck, because this guy had an idea about everything) and a researcher (not so much luck, he only knew about some of his favourite beta-particles, a classical example of a "fachidiot").

Probably the first time somebody played the blues harp down in those accelerator-tunnels (me) ;)

Computer Games - Les Horribles Cernettes

The first band on the web shares their songs freely in mp3 format, with no DRM. Look how far we've come... sigh.

Computer Games - Les Horribles Cernettes

The first band on the web shares their songs freely in mp3 format, with no DRM. Look how far we've come... sigh.

Some of it's beyond satire and into pathos; take a look at My Sweetheart Is A Nobel Prize.

My sweetheart's a Nobel Prize
My sweetheart's so smart and wise
My sweetheart is a Nobel Prize

He says a lot of things that I dont' know,
But I do know
That I'll do anything he wants me to,
'cause I do love him
I don't understand
The funny signs on his blackboard
But when he holds my hand
He takes me to the stars

Nothing against sounding like a total bimbo, obviously, but if they're going to lay on the dribbling ignorance this thickly they might as well just go the whole hog and just go with dribbling vacantly into the microphone.

Bah.

Tee-hee. Interesting.

http://musiclub.web.cern.ch/musiclub/bands/cernett es/songs/on_the_web.html

Here is a direct link to the picture to save bandwidth.

Gasp! Girl geeks! Be still my beating heart!

Vital measurments: 503px by 400px w00-w00!

Gasp! Girl geeks! Be still my beating heart!

Vital measurments: 503px by 400px w00-w00!

It's not your house - it's all the stuff IN your house. Worst offenders are generic PCs; specifically their case design (RFI/EMI-wise) is absolutely clueless (e.g., see http://www.ac6v.com/comprfi.htm/ for theory and fixes). Second place is firmly held by very, very crappy power supplies that let all the noise OUT of the PC on the power buss (ie. into your wiring). Sam's very useful Notes on the Troubleshooting and Repair of Small Switchmode Power Supplies) will get you started with theory and what [often] goes wrong (disclosure: I'm his sidekick). But:

Pet Peeve: as soon as Name-Your-$14-PC-PS-Manufacturer gets their UL sticker (meaning they can start selling in the US!) the ENTIRE L-C filter from the input of the power supply PCB is shorted out with a series of jumpers. Right, the 120VAC wires go through the save-thy-ass fuse right into the rectifier! No caps, no chokes, nuthin'! (Ok, so what do you expect from a $15 460W PS?) This allows all the noise on the power lines to enter the PC (and fry it - use a surge protector!) *AND* it allows all the noise IN the PC to escape back out and corrupt others (ie. your receiver, TV, etc.) (See: http://cms-emc.web.cern.ch/cms-emc/pdffiles/PhDfil es/PS&filters.pdf section 3.2 Switching mode power supplies for a nice overview). Oh, yeah, and I'm *SURE* all of you have your grounded cable actually grounded, right?

I got a 250W ATX knock-off case for $29 that came with a PS included. Turned the PC on, *ALL* AM stations vanished! Right... I opened it up and shure enough, a jumper from fuse to rectifier. All caps to ground were missing as well (from various points in the circuit). A few moments with a soldering iron (jelly-bean components, salvaged from dead *quality* PSes) and you can't tell the PC is on by listening to AM dial. Day and night difference!

Don't feel bad if you never though of it, this guy obviously never did either... and he should have. http://techreport.com/reviews/2004q4/psus/index.x? pg=1

But, how do you later chop up the files? I'm glad you asked: I use a hacked version of text-only (yeah!) soundgrab. You can get my latest version from http://repairfaq.ece.drexel.edu/filipg/soundgrab/

My signal comes from a battery-powered (ie. avoids issues with 'corrupted power' ;) digital sony walkman, via a 20-odd foot coax cable to my PC. The further away your receiver is from the source of noice, the better off you are![*] Linux records it from a SoundBlaster Live! with rawrec to a wav file. I have a series of templates (.sg files) for different shows and just fudge them a bit then export to MP3. Piece of cake! I've done a bunch of Dave's shows that way (~700MB worth) for inclusion in a weakness of mine (don't worry, they get some equally-illegit music ;).

Cheers

[*] "The solution to pollution is dilution" - Evil chemistry maxim applied to the wonderul and friendly world of RFI ;-)

I call bullshit.

If 'greenhorn' C++ developers can make an app that is even ONE PERCENT faster, then the Java Developers WERE NOT 'highly skilled'. Period. But TWICE as fast? As in, C++ takes 1/2 the time to execute 'x' as the Java version? No way. Not even if we are talking linear algebra code*.

An experienced Java programmer knows you have to memory manage large apps. Yes, Java will *always* use more memory than an equally well written C++ app; however, unless you are working *exclusively* with *huge* arrays, java will be damn near as fast, and often faster than equivilent C++ code. Hell, if those arrays have to be collected in C++, Java will be faster. *UNLESS* you optimize the living crap out of your C++ code and ignore optimizations on your Java code.

I have *plenty* of issues with Java (for instance, who the f*ck decided on a 64MB default max memory space for the JVM?). Speed has always been one of my Java PLUS points.

* A quote for the lazy:
"For example, IBM Watson's Ninja project showed that Java can indeed perform BLAS matrix computations up to 90% as fast as optimized Fortran."

this one: http://info.cern.ch/hypertext/WWW/TheProject.html. (in the WWW announcement)

http://www.intel.com/research/silicon/mooreslaw.ht m

The Gentleman that came up with Moore's Law doesn't agree with you. I trust Gordon Moore more than almost anyone on /.

Kind of funny that way.

From the above link.

Gordon Moore made his famous observation in 1965, just four years after the first planar integrated circuit was discovered. The press called it "Moore's Law" and the name has stuck. In his original paper, Moore observed an exponential growth in the number of transistors per integrated circuit and predicted that this trend would continue. Through Intel's relentless technology advances, Moore's Law, the doubling of transistors every couple of years, has
been maintained, and still holds true today. Intel expects that it will continue at least through the end of this decade. The mission of Intel's technology development team is to continue to break down barriers to Moore's Law.

Link to his 1965 paper ftp://download.intel.com/research/silicon/moorespa per.pdf

Link to info about the misuse of the 'law' http://gridcafe.web.cern.ch/gridcafe/Gridhistory/m oore.html

But then again, what does CERN, Intel, and Mr. Moore know about any of this?

And if my 1337 seer skillz are to be trusted, the next 35 will be at least as informative, funny, cooperative, and interesting.

Last week we celebrated
the 50th anniversary of CERN (European Laboratory for High Energy Physics).
There was an "Open Day" organized (visits to tens of interesting places at CERN) and the Computing Center was one of the most popular places.
I was honoured to be one of the guides there.

The LHC will produce proton-proton collisions 40 million times per second.
Even after a first pre-selection of the events, there will be around 100 "potentially interesting" events per second that have to be recorded for further (so called "off-line") analysis.
There will be 4 detectors running on LHC (ATLAS, CMS,LHCb and ALICE).
The size of the data describing a typical "event" (collision) depends on the detector, but it is of order of Megabytes.
Assuming 1MB/event/detector that gives

1MB*100events/s*4 detectors*86400s/day=
34560000 MBytes of data produced every day.
That is almost 35 Terabytes of data per day (24 hours).

We expect to have some 10 Petabytes of data per year. And we hope to run the LHC for some 20 years.
Obviously, this amount of data cannot be stored/analysed locally; it will be therefore transmitted to scientific institutes worldwide.

You may have a look at the presentation:
[PPT]
PDF

The answer to computing power is the Grid: more information at http://gridcafe.org/

cheers,
Piotr Golonka
CERN IT/CO

Last week we celebrated
the 50th anniversary of CERN (European Laboratory for High Energy Physics).
There was an "Open Day" organized (visits to tens of interesting places at CERN) and the Computing Center was one of the most popular places.
I was honoured to be one of the guides there.

The LHC will produce proton-proton collisions 40 million times per second.
Even after a first pre-selection of the events, there will be around 100 "potentially interesting" events per second that have to be recorded for further (so called "off-line") analysis.
There will be 4 detectors running on LHC (ATLAS, CMS,LHCb and ALICE).
The size of the data describing a typical "event" (collision) depends on the detector, but it is of order of Megabytes.
Assuming 1MB/event/detector that gives

1MB*100events/s*4 detectors*86400s/day=
34560000 MBytes of data produced every day.
That is almost 35 Terabytes of data per day (24 hours).

We expect to have some 10 Petabytes of data per year. And we hope to run the LHC for some 20 years.
Obviously, this amount of data cannot be stored/analysed locally; it will be therefore transmitted to scientific institutes worldwide.

You may have a look at the presentation:
[PPT]
PDF

The answer to computing power is the Grid: more information at http://gridcafe.org/

cheers,
Piotr Golonka
CERN IT/CO

Last week we celebrated
the 50th anniversary of CERN (European Laboratory for High Energy Physics).
There was an "Open Day" organized (visits to tens of interesting places at CERN) and the Computing Center was one of the most popular places.
I was honoured to be one of the guides there.

The LHC will produce proton-proton collisions 40 million times per second.
Even after a first pre-selection of the events, there will be around 100 "potentially interesting" events per second that have to be recorded for further (so called "off-line") analysis.
There will be 4 detectors running on LHC (ATLAS, CMS,LHCb and ALICE).
The size of the data describing a typical "event" (collision) depends on the detector, but it is of order of Megabytes.
Assuming 1MB/event/detector that gives

1MB*100events/s*4 detectors*86400s/day=
34560000 MBytes of data produced every day.
That is almost 35 Terabytes of data per day (24 hours).

We expect to have some 10 Petabytes of data per year. And we hope to run the LHC for some 20 years.
Obviously, this amount of data cannot be stored/analysed locally; it will be therefore transmitted to scientific institutes worldwide.

You may have a look at the presentation:
[PPT]
PDF

The answer to computing power is the Grid: more information at http://gridcafe.org/

cheers,
Piotr Golonka
CERN IT/CO

Let us not forget CERN's early work with the www client and wwwd server. In particular, the work of Tim Berners-Lee. That link includes some web history.

Let us not also forget NCSA Mosaic, which became a "killer app" in the early/mid 1990s, before being spun off as SpyGlass.

My memory is faulty, but I believe more than half of the NCSA team left the project and formed NetScape. Can anyone correct this?

The web as we know it also owes a debt to previous research in hypertext systems dating back decades, as well as existing document-markup systems.

To those who keep Mozilla alive today:
I salute you, but do take too much pride in yourselves:
Never forget that you stand on the shoulders of giants.

One of the potential problems with antimatter is how to use it. If one just removes it from its isolation container, it may just glow, spit and fizzle for an extended period of time, rather than explode properly.

Is that actually a bad thing in a bomb ? Remember that the glow here is still much hotter than Suns surface, propably hotter than it's core. If, for example, you would make this into a thin disk with a hole in the middle (or a donut), you could send normal matter into the edges of that hole, causing the disk to spread over a large area, spreading out the destruction. Sure, it will decrease the power of the explosion at ground zero - but then again, does it really matter if the explosive power is enough to annihilate everything at said point 10 or 100 times ? Making the area of total destruction larger - now that's a usefull feature in a weapon of mass destruction.

In any case, a bigger problem might be that it would take 2.5 million years to product 250 grams of antimatter (the equivalent to a 10 MT hydrogen bomb), assuming all of Earths energy production would be channeled towards this task (says this page).

I was lucky enough to visit Swizterland this summer. Spent most of my time around Geneva. Saw the CERN visitor center, and saw the very first web server, a NeXT cube. Waited too late to get reservations in time to get the full tour. Anyway, this whole business of the cows eating trees to clear the mountain views sounds a bit odd. I really doubt the Swiss are that stupid. We went and saw the Matterhorn and the only thing that obscured the view was clouds. It finally cleared up enough so we could see 90% of the mountain. Zermatt was like a big Disney attraction with lots of Japanese tourists.

I visited Gruyere and saw the castle and the H.R. Giger Museum.. He's one sick puppy. Had a beer at his Giger Bar. That was cool. Gruyere is of course famous for it's cheese. We took the took the tour of the cheese factory at the base of the mountain. We had an electronic device that we could punch in a number and hear the narration for each station. Our narrator was Cherry the Cow. She informed us when drinking her milk you could taste EVERYTHING she's ever eaten.

No one should try to read the acronym.

Indeed. Any name including the word "nuclear" in it, will systematically scare off the mass audience. "Nuclear" is too much linked to Chernobyl, nuclear power plant, nuclear bomb. A detail you think? Not at all, see CERN home page... And the result is "The world's largest particle physics laboratory". See the CERN in seven questions. Emphasis is put on "particle physic" not on "nuclear"

Research performed at CERN is so abstract that no common mortal can imagine what is done there. The name of the institution is the only thing one can hang on. Actually "CERN" is still in use because it is in too many places to be replaced. But officially the lab should be referred to as something like "particle physics laboratory".

External image is actually pretty important to CERN. Because CERN always have to answer the tax payer's question "why the heck am I giving money for some dark fundamental whatever?" If the answer contains a "nuclear" somewhere, that's already a bad feeling passed on. I worked there a short while. One of my guru told me: "computer science there is 50% tech, 50% psychology". I guess CERN public advertisement is 95% psychology. Not to be underestimated.

I love CERN. :-)

And if you wonder about the sheep on the CERN grounds, they are living dosimeters.

Are you sure about this? I'm actually kind of curious, because CERN is not exactly the kind of place you'd expect to see a bunch of sheep grazing. The story I've heard (quite possibly an urban legend of sorts) is that back in the day, some king decided that a certain family would have permanent grazing rights to the land that CERN would eventually be built on, and when CERN was built, the organization had to respect those grazing rights.

After some cursory googling, I was unable to find any webpage that substantiates this story, but it does seem that the sheep are privately owned. (This webpage briefly mentions the "privately owned sheep" at CERN.) If you (or anybody else) can point me to an authoritative explaination of the sheep, I'd appreciate it... :)

To be honest, I find the "living dosimeters" explaination a little hard to believe on a number of levels. The sheep aren't always in the same place (I see them only sporadically on the hill in front of Restauant 2), they're privately owned, and besides, how do you get a good measurement of radiation levels out of a bunch of sheep? :)

CERN is a perfectly valid acronym since 1954, when the steering committee decided to keep this handy acronym to designate the research center.

CERN is well worth a try for people who want some experience with working in other countries. AFAIK you need to be started on undergraduate studies in physics, engineering, or computing, and be good at English OR French. First time engagements are normally between two months and three years. The recruitment website explains most of what you need to know. See you here!

From the LHC@Home FAQ:
"1.2 What does LHC@home do?

LHC@home helps the construction of LHC. It simulates how the particles travel trough the 27 km long tunnel. With the help of the calculated information, the magnets that control the beam can be calibrated with greater precision."

Here's the LHC home page for those who want more than a fluffy news media article
http://lhc-new-homepage.web.cern.ch/lhc-new-homepa ge/

Finally, no more compiling a 30 line program just to see if a bit of code will work."

See also the Free CINT and TCC.

Larry

Folks around the world have been producing antiparticles for quite some time. They're also created by natural processes, but don't last long in high matter density environments.

Folks around the world have been producing antiparticles for quite some time. They're also created by natural processes, but don't last long in high matter density environments.

Really, to blame Europe now for its past imperialism is silly. And in all fairness, America did expand itself to stretch across a continent. And then when we did that, we found new frontiers like China, Hawaii, and the Philipines.

As far as I know, European countries no longer have any colonial holdings, and the most America has is Puerto Rico.

When people talk about imperialism now, they're often referring to corporate imperialism, because it's a lot harder to come up with a moral justification (i.e. "uplifting and Christianize" our "little brown brothers" -Mckinley) nowadays, though Bush is sure giving it a hell of a try ("axis of evil" "spreading democracy").

Also, what major technological divisions are there? Out of curiosity. I don't have much knowledge on the subject, but it seems to make sense that allies would keep each other fairly updated on advancements, so a large technological disparity seems a bit odd.

Caveat Emptor.
There's no such thing as a free lunch. If it looks to good to be true, then it probably is.

How about serverless peer-to-peer?

Ok, what do I know?

I know I'd follow CERN's advice.

The CERN link should look like this.

You're wrong. Actually higgs to 4 leptons is one of the main channels through which ATLAS will look for the Higgs boson. Remember that you can have positively and negatively charged muons ... so electric charge conservation is certainly NOT violated. For more information, here's a physics poster which mentions the 4 lepton decay.