Cu Kα pulse generation in an X-ray tube with a plasma cathode induced by a femtosecond laser pulse

An X-ray tube has been developed with a femtosecond laser-produced plasma at a Cu cathode by the acceleration of the plasma electrons onto a Cu anode. The source provided a Cu Kα pulse with 109 photons/4π and ≅100 ns width. Spectral observations of visible emissions from the cathode have revealed that the excitation of the plasma occurs on the same time scale as the X-ray-pulse generation, indicating that the electrostatic shielding of the plasma gradually breaks under the applied electric field.