All-optical Compton gamma-ray source

Abstract

One of the major goals of research for laser-plasma accelerators is the realization of compact sources of femtosecond X-rays. In particular, using the modest electron energies obtained with existing laser systems, Compton scattering a photon beam off a relativistic electron bunch has been proposed as a source of high-energy and high-brightness photons. However, laser-plasma based approaches to Compton scattering have not, to date, produced X-rays above 1 keV. Here, we present a simple and compact scheme for a Compton source based on the combination of a laser-plasma accelerator and a plasma mirror. This approach is used to produce a broadband spectrum of X-rays extending up to hundreds of keV and with a 10,000-fold increase in brightness over Compton X-ray sources based on conventional accelerators. We anticipate that this technique will lead to compact, high-repetition-rate sources of ultrafast (femtosecond), tunable (X- through gamma-ray) and low-divergence (~1 degree) photons from source sizes on the order of a micrometre.Comment: 6 pages, 5 figure

Atomic Auger Doppler effects upon emission of fast photoelectrons

“…There is now-a-days an important development of radiation sources using a laser plasma accelerator in the few hundreds keV energy range 30 . In this energy range, the Doppler splitting in the Auger spectra can become very high (for example, 2 eV for the Ne 1s À 1 -2p À 2 ( 1 D 2 ) Auger transition at 500 keV) and the structures are separated, allowing the polarization to be determined, again, as in the previous example, by measuring relatively slow Auger electrons instead of very fast photoelectrons.…”

MeV-Energy X Rays from Inverse Compton Scattering with Laser-Wakefield Accelerated Electrons

“…More recently, a single laser pulse is used to both accelerate the electrons and scatter (after reflection from a plasma mirror) [8]. While hard x rays are produced in this latter case (peaked at $50 keV), the photon energy is still well below the thresholds for photonuclear processes.…”

“…A cross-correlation technique was used to characterize the source sizes of both the electron beam and -ray beam, by scanning the scattering laser pulse across the electron beam. This design is also free from the debris contamination and bremsstrahlung background, both of which are inherent to the single-laser-pulse approach [8]. Characterization of higher energy x rays required both the development of a novel detection method as well as implementation of a novel numerical scattering model.…”

Standoff detection of hidden objects using backscattered ultra-intense laser-produced x-rays

“…To realize a compact collimated pencil X-ray source, one possibility is inverse Compton scattering from a laser-driven electron. [19][20][21][22] For example, when electrons with an energy of 150 MeV (Lorentz factor c of 300) scatter a counter-propagating laser with a wavelength of 0.8 lm (corresponding photon energy L of 1.6 eV), the resulting inverse Compton scattering light has a divergence of 1=c $ 3:3 mrad and an energy of 4c 2 L $ 558 keV. By using the proposed inverse Compton scattering light as a primary X-ray source, the attenuation of the primary X-ray can be maintained at 5% at a distance of 10 m. This level of attenuation is expected to be trivial in practical applications.…”