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.
Each machine offers a different level of accuracy and ability to deliver various radiation techniques to treat the target. A Linear Accelerator (LINAC), the most common type of radiation machine, uses electricity to form a stream of fast-moving subatomic particles (Fig. 4). The radiation beam produced by a LINAC can be shaped and aimed at the target from a variety of directions by rotating the machine and moving the treatment table.