Betatron-type laser-plasma x-ray sources generated in multi-electron gas targets

摘要

Betatron-type laser-plasma x-rays are recorded simultaneously with their corresponding relativistic electron spectra in a laser wakefield acceleration scheme. The role of the multi-electron gas target in the betatron-type x-ray efficient generation is experimentally examined. A proof of principle experimental study shows that by using a multi-electron gas target and appropriately adjusting the pumping laser intensity an increase in betatron-type x-rays efficiency could be achieved. This is attributed to sophisticated control of the type of the electron injection inside the plasma bubble related to the tunneling ionization process occurring after the laser pulse peak. This method depends primarily on the gas target charge state chosen for attaining the ionization injection scheme and could be extended to a wide range of relativistic laser intensities.