<p>Steve Jurvetson in 2004, from his own Flickr account. 
</p><p>His description of the photo: You may notice the overcast sky.  Down the road is the Y-12 Plant, the last full scale nuclear weapons production facility in the U.S.  This site was originally chosen because of the high average cloud cover (for spy planes and satellites), and it now houses several DOE projects.
</p><p>Behind me is the spallation target area, which will house several tons of liquid mercury in a large tank.  A large <a rel="nofollow" class="external text" href="http://www.sns.gov/aboutsns/source.htm">linear accelerator</a> runs off to the right to bring a 1 billion eV proton beam into the mercury to release neutrons into various instruments (e.g., for <a rel="nofollow" class="external text" href="http://www.sns.gov/aboutsns/importance.htm">soft tissue imaging</a>).
</p>
This facility will produce 10x as many neutrons as the prior record holder, and it is the first to use a mercury target.  Cost: $1.4 billion.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/44124348109@N01">Steve Jurvetson</a> from Menlo Park, USA
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/44124348109@N01/1579052/">Spallation Neutron Source</a>