Compact X-ray Radiation Therapy Device Based on a Laser-wiggler

Background: X-rays are essential to a variety of medical applications such as imaging and cancer radiation therapy. The common mechanism in radiation therapy today is based on relativistic electrons bombed onto a metal target. The full configuration is enclosed in a treatment head, which is usually one meter long. In this work we present a configuration for an X-ray free electron laser with a compact size of a few centimeters, which may lead to less tissue damage in cancer treatments, enable mobility of the devices, and might also reduce costs. The scheme is based on a laser-wiggler, which relies on a TEM laser mode confined by a Bragg waveguide. The laser`s electric field induces transverse oscillations of the counter-propagating electron beam, resulting in an X-ray emission.

Methods: The model of interaction dynamics between the laser and electron beam in the wiggler is formulated and simulated for an amplifier mode, in which a pre-designed X-ray seed is injected.

Results: The emerging coherent X-ray (0.25 nm), for a 2 cm long configuration with 50 MeV electrons, has an output power of ~1 Watt, corresponding to roughly one photon for each electron.

Conclusion: By utilizing a similar electron beam energy (tens of MeV), our device yield of photons per electron (~1) is nearly two orders of magnitude higher than existing medical devices (~0.02), while facilitated in an order of magnitude smaller device.