Synchrotron FELs are already used, and their construction paid for due to their scientific uses. Building new ones would require new synchrotrons, which are mor

Synchrotron FELs are already used, and their construction paid for due to their scientific uses. Building new ones would require new synchrotrons, which are more expensive than the crazy "hit molten tin drops with lasers to make a plasma" scheme the ASML machines use.