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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."
so I have nothing to say
about $82,200/day just in electricity costs.
Yes, something like that. The instrument at full output is supposed to be 1.4 MW. Assuming 5$/kWhr (note that big installations end up paying less per kWhr, on average, than a residential user) that's over $100,000/day in electricity costs. Of course when running this delivers neutron beams along all of the beam tubes. When fully operational, there should be 24 beamlines, meaning that each researcher is "only" costing ~$5000/day in electricity.
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.
As far as I know, that's not how it works. The researcher does not "pay" outright for the beamtime (although companies renting beamtime do). What happens is that a researcher makes an application for beamtime. Like any other grant, this is reviewed by experts. If the proposal is accepted, the researcher gets the beamtime (for "free"). So instead of giving government funds to researchers, who then buy beamtime, the SNS is funded and divides out the beamtime to researchers worldwide, based on the scientific merit of the proposals.
I'm not 100% sure that's how the SNS will be run, but that is how such "user facilities" have been run in my experience. The SNS is a government-funded facility whose goal it is to "get important science done" and as such its top priority is to divide up the beamtime to researchers (from around the world) without "wasting any beam-time" and hopefully giving opportunities for the best science to be completed (regardless of how much money the research group has).
"...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.
So, what's the point of this thing?
The purpose of a "neutron beam" is *neutron scattering.* You can either use a continuous beam from a nuclear reactor, or a neutron pulse from a spallation source (which the SNS is). The idea is that you sent the beam at your (scientifically interesting) sample, and measure the directions and energies of the neutrons that are scattered/reflected/diffraction from the sample. This is a huge field, but here are some ideas of what it can be used for:
1. Neutron diffraction can be used for crystallography: to determine the crystal structure (hence molecular structure) of some novel material, drug, protein, etc. This can be done with x-rays also, but for some samples neutrons give better results.
2. Neutron reflectivity can be used to study thin films: to analyze coatings applied to electronics, or anti-abrasive coatings, or membranes used in medical applications, and so on.
3. Neutrons can be used to study industrial materials: for instance, a neutron beam can be used to probe a weld joint and map out the 3-dimensional arrangment of microsocpic stress patterns in the material. This has been used to design better welding processes, better aircraft components, engine parts, and so on.
4. A neutron beam can be used for "imaging" similar to an x-ray... except that neutrons can pass through dense materials (like lead) quite easily and can image organic materials with better sensitivity than x-rays.
5. Neutron beams can be used for the study of nuclear physics and chemistry, the properties of neutrons, and other particle-physics questions.
There are of course many other things you can do with a neutron beam, but hopefully that gives you an idea of the diversity of research that goes on at a neutron scattering facility.
I doubt that would attract 2,000 international scientists annualy
Well there is quite a bit of demand for neutron beam-time. Since the SNS will take the flux up a notch (8 times higher than anything we have now), researchers will be able to complete their experiments faster (or conversely complete more experiments in a given timeslot), and will also be able to detect things that perhaps went unnoticed before. So yes, there will quite a bit of demand for this installation.
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.