Quote:
Originally Posted by RWebb
[1] do you guys use neutrons to cause spallation?
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Like bk mentions, we use a proton beam to create neutrons by accelerating the protons to ~ 90% of the speed of light and then focusing them into a beam of approximately 20mm x 70mm and directing them onto a liquid mercury target. Lots of protons. Like 10E14 protons per pulse at a rate of 60 pulses per second. Mercury - with it's high molecular weight - has plenty of extra neutrons to "knock off" when struck by the proton beam. Mercury also has the nice property of being a liquid at room temperature, so we can carry the heat energy deposited by the proton beam away. The spalled neutrons are then moderated, reflected and focused down beam lines where scientists use them to discern details of atomic structures in a similar (only better due to the neutral charge of neutrons) method to x-ray diffraction.
Downsides - the proton beam degrades the materials in the target facility by displacing atoms within the molecular structure causing radiation-induced embrittlement among other things, so my job is to replace these screaming-hot items as they reach their limits. We have to ship these items off for burial, hence the photos above of our current shipment. Another downside is that highly radioactive (thousands of R) mercury is nasty stuff.
All in all, though, an extremely cool place to work. Absolute cutting edge of accelerator and pulsed neutron technology.