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First Neutron Pulse from SNS
kebes writes "The $1.4 billion Spallation Neutron Source is nearing completion, and has produced its first neutron pulse. The SNS is a scientific instrument that generates beams of neutrons, which can be used to probe anything from minuscule samples to industrial materials. When fully operational, the facility is expected to host up to 2,000 international scientists annually."
We've had one of those for a while now, on this side of the pond. http://www.isis.rl.ac.uk/ They are building a second target at the site, due to open in 2008.
'The machine is so powerful that in one year it will use about the same amount of electricity as a town of 30,000.'
If we assume that the average person has an electric bill of $1000/yr, that would be $30,000,000/yr, or about $82,200/day just in electricity costs.
I imagine that lots of scientists would want to play around with this- I would certainly have fun with it given the chance. At that price, though, only extremely well-funded researchers could afford to use this machine.
You are reading a copy of my copyrighted post.
so I have nothing to say
..if at the time of unveiling the project one of the scientists says in british english: "Now this station is Fully Operational!" :)
Uh, okay, not quite sure what this thing actually does? Except fire neutrons at stuff... but while I'm sure that's an amusing thing to do, I doubt that would attract 2,000 international scientists annualy. So, what's the point of this thing?
GAAH! MY PRINTER IS ON FIRE!!! PUT IT OUT! PUT IT OUT!
"...which can be used to probe anything from miniscule samples to industrial materials."
Sure, it starts out that way, but before you know it you've opened up a gateway to another dimesion.
Please, do us all a favor and keep plenty of weapons and ammo around the facility. Oh, and make sure whoever's wearing the hazmat suit has a crowbar with them at all times.
Demented But Determined.
...I've got to say it anyhow:
First Atom: I just lost an electron
Second Atom: Are you sure?
First Atom: Yeah, I'm positive.
This ain't rocket surgery.
From the facility's website:
http://www.sns.gov/aboutsns/benefits.htm
Oolite: Elite-like game. For Mac, Linux and Windows
Actually, i forget the article, but a physicist did genunely suggest using a neutrino (not neutron) beam to cause enermy nuclear weopeans to melt down in there casings. It seemed reasonably practicle as well, it
would require a very high current particle accelerator to produce a very narrow ultra relavistic pion or
muon beam. At these high speed the neutrino decay products of pions would still be very tightly directioned. They could pass straight through the earth, and cause sufficient stimulated fission reactions in remote nuclear materal to cause it to gently (as opposite to explosively) melt down.
The trick is that SNS produces a lot more of them and in a beam. You can't focus neutrons as efficiently as you can light or electrons.
Thanks to the posters who pointed out the mistake in my previous post. Indeed power is typically on the order of 5 cents/kWhr. I also confused the discussion by mentioning the 1.4 MW that the SNS is rated for. The 1.4 MW is the power delivered to the target. It requires about 42 MW to generate that 1.4 MW proton beam. So we're talking about:
42,000 kW * 0.05 $/(kW hour) * 24 hours/day = 50,400 $/day
(Hopefully I haven't made a mistake this time.) This is a lot of money, but really not such a big deal for a facility this size.
Actually its pretty straight forward - whack a bunch of protons into a target and neutrons drop out. The protons react with nuclei in the target to produce neutrons (and pions and a whole load of other junk). The protons need to be reasonably high energy (say at least relativistic) to get a good neutron yield.
Usually you use a heavy metal as the target. High nuclear mass so that there are lots of protons and neutrons to collide with, high melting point/tough so you don't damage the target too much when the protons go into it. The target is probably actively cooled or you might want to try a liquid metal target at high intensities so that it cools itself. Watch out that you can build pipes to contain the liquid that aren't destroyed by the incoming proton beam. Then you collimate the neutrons coming out and possibly slow them down using something like carbon.
Jobs a good 'un!
Anyone remember UCLA doing a form of cold fusion using pyroelectric crystals? It did not release enough energy to make it efficient as an energy source, but I recall the article saying it would make a portable neutron source. Perhaps that could be used to make a smaller and more efficient version of the Oak Ridge facility.
IANAPP (I am not a Particle Physicist) but I *DO* work at the SNS site. I'm a software engineer in their Beam Diagnostics group, and was in the contorol room on Friday when we met this milestone. My basic understanding is that here we use our Linac to accelerate protons (H-). A minipuse sent down the linac is approx 700 ns long. They first go into an accumulator ring, and are "stacked" to increase the intensity of the pulse to target. On Friday we accumulated for around 180 pulses, design specs are for around 1000. Finally the the pulse is extracted from the ring and hits a target vessel filled with mercury. Again, IANAPP, but my understanding is that this intense pulse of protons only 700 ns long, hits the mecury, and "spalls" neutrons from the mercury atoms. Then as others have mentioned the neutrons are columnated and fly down different beam lines to be used in different refraction experiments (or they will be once this source is fully operational ;-) . Bottom line is that the particles that we acclerate are not the ones that contribute neutrons. Once more, IANAPP, but it helps me to think of it as we're accelerating cue balls, and hitting a (3D) rack of billard balls.
Firstly, they're neutral, so the charge of electrons or lattice ions they scatter off of won't give any extra Coulomb repulsion, as it would if they used proton or electron beams for scattering.
Additionally, they're massive, so the interaction will be different than X-Ray scattering.
But one of the most important characteristics is that neutrons have a spin of 1/2, and this spin looks like a small magnetic moment. So the neutrons can give useful information about magnetic interactions in the sample. Many people are studying interesting ferromagntic or anti-ferromagnetic interactions of whole new classes of materials with neutron scattering. This is also important for spintronics, where the neutrons will scatter differently off of a particle if that particle is spin-up vs spin-down.
The neutrons interact nicely with the lattice in a crystal, and with the energies involved they are a great tool for looking directly at phonon modes of the sample.
Is it scalable to the power levels given by the Spallation source? How focused can the beam be? What is the energy dispersion of emitted neutrons, compared to the Spallation source?
This is kind of a crappy Slashdot item, as it links to a Yahoo-hosted news article that will be gone in a month. Yahoo collects and temporarily hosts news items. Their links are dead usually after about a month, in my experience. Future readers won't be able to use the link given in the OP. Wayback doesn't archive Yahoo-hosted articles either, so far as I know. Users can get the same Associated Press article here or here.
I find it annoying when I read a Slashdot item from yesteryear and the links are dead. When you link to Yahoo, you're ensuring that you're giving a link that'll be worthless in the not-too-distant future.
Just take a second to search for the name of the article in Google News or something to get a more permanent link. It's not hard.
Eh?