Doughnut

Up early for the flight down to Southampton.  A fox trotted through the garden as I was eating my breakfast - looked like it had a white pom pom on the end of its tail.

I spotted this interesting building from the air on my way into Southampton Airport.  Anyone know what it is?

Edit: It's a synchrotron:
https://www.diamond.ac.uk/Home/About.html

Crop circle in the extra.