Quasi-monoenergetic electron beams from laser plasma acceleration using nitrogen gas jet

An experimental investigation on laser plasma acceleration of electrons has been carried out using 3 TW, 45 fs duration titanium sapphire laser pulse interaction with nitrogen gas jet at intensity of 2x10^18 W/cm^2. We have observed stable generation of well collimated electron beam with divergence and pointing variation ~ 10 mrad from the nitrogen gas jet plasma at an optimum plasma density around 3x10^19 cm^-3. The energy spectrum of the electron beam was quasi-monoenergetic with average peak energy and charge around 25 MeV and 30 pC respectively. The results will be useful for better understanding and control of ionization injection and laser wakefield acceleration of electrons in high-Z gases and also to develop practical laser wakefield accelerators for various applications including injectors for high energy accelerators.