DWA addresses the main issues with the current proton therapy systems—cost and size. Depending on the desired final beam energy, the conventional medical accelerator solutions (cyclotrons and small synchrotrons) can have large cost factors and space requirements, which could be circumvented by DWAs. The cost estimate for a DWA is about 20 million US dollars. DWAs are expected to reach acceleration gradients around 100 MV/m. The system is a spinoff of a DOE device to inspect nuclear weapons. This system requires several new advances because of the high energies, e.g., high gradient insulators. A wide band-gap photoconductive switch, about 4,000, is needed. A Symmetric Blumlein, typical width 1mm. References External links Dielectric Wall Accelerator G. J. Caporaso, Y.-J. Chen, S. E. Sampayan September 3, 2009, Reviews of Accelerator Science and Technology High Gradient Dielectric Wall Accelerators Muon Collider Design Workshop, December 8–12, 2008, Thomas Jefferson National Laboratory Ultra‐High‐Current Electron Induction Accelerators Physics today [0031-9228] Kapetanakos, C yr:1985 vol:38 iss:2 pg:58 US Patent 7924121 Dispersion-Free Radial Transmission Lines, April 12, 2011 Accelerator physics