High peak pulse power operation of the OK-4/Duke XUV FEL

The Compton backscattering process and radiotherapy

“…The range of energy of the latter is considered for that which might be produced. 11,13 The completely backscattered photon energy ͑ប BS ͒ rises linearly with an increase in incident energy according to Eq. ͑6͒.…”

“…In other words, the flux of photons must be sufficiently high enough to treat patients in minutes. Based on the technology available at this time, 13 there is the opportunity to achieve this for energies less than 40 MeV. In the following, that energy region is emphasized.…”

“…A method for practical achievement of these collisions is possible using free electron lasers. [8][9][10][11][12][13] A linear accelerator is used to store an initial bunch͑es͒ of electrons in an electron storage ring. 12 The electrons themselves are used to generate the collision photons ͑energy ϳ eV range͒ with a precision of 0.03%, using a continuously tunable undulator.…”

“…12 The electrons themselves are used to generate the collision photons ͑energy ϳ eV range͒ with a precision of 0.03%, using a continuously tunable undulator. 13 Amplification of this light is achieved via a lasing process. 8,9 A radiotherapy system would require that the scattered ͑recoil͒ electrons are refocused into the electron beam by the storage ring.…”

“…6,7 Some backscattered Compton gamma-ray facilities operate by scattering conventional laser light against electrons accelerated in a linac or circulating in a storage ring. [5][6][7] Recently, continued interest in electron storage rings and free electron lasers [8][9][10][11][12][13] has opened the possibility of high-power production of backscattered Compton beams. In this paper we review the underlying theory and presents results of interest to future radiotherapeutic applications.…”