Intense gamma-ray source based on focused electron beams from a laser wakefield accelerator

Laser wakefield accelerators generate ultrashort electron bunches with the capability to produce gamma-rays. Here, we produce focused laser wakefield acceleration electron beams using three quadrupole magnets. Electron beams are then focused into a 3 mm lead converter to generate intense, focused bremsstrahlung gamma beams. Experimental results demonstrate the generation and propagation of focused gamma beams to a best focus spot size of 2.3 & PLUSMN; 0.1 x 2.7 & PLUSMN; 0.2 mm(2) using a copper stack calorimeter. Monte Carlo simulations conducted using GEANT4 are in good agreement with experimental results and enable detailed examination of gamma-ray generation. Simulations indicate that the focused gamma beams contained 2.6 x 10(9) photons in the range of 100 keV to 33 MeV with an average energy of 6.4 MeV. A gamma-ray intensity of 7 x 10(10) W/cm(2) was estimated from simulations. The generation of focused bremsstrahlung gamma-ray sources can have important applications in medical imaging applications and laboratory astrophysics experiments.