As far as the tile roofs, they last a long time. It isn't the tile that is the issue, it's the felt (or paper) underneath that gets replaced. Mine is 25 years old, has not been replaced yet. Some neighbors have had theirs redone, but many have not as yet. 04-06-2011, 12:00 AM.
Smaller particle accelerators are used in a wide variety of applications, including particle therapy for oncological purposes, radioisotope production for medical diagnostics, ion implanters for manufacture of semiconductors, and accelerator mass spectrometers for measurements of rare isotopes such as radiocarbon.
The early particle accelerator was invented by John D. Cockcroft and Ernest Walton, who worked in the Cavendish Laboratory, in Cambridge, England. When they started investigating, in 1930, they used a 200-kilovolt potential with a straight discharge tube to accelerate protons.