Electrons accelerated by tightly focused relativistic laser pulse for single shot peak intensity diagnostics

A novel technique of peak intensity evaluation of tightly focused femtosecond laser pulse is proposed. The method is based on numerical and experimental studies of electrons angular distribution at acceleration in the field of laser radiation interacting with low density ( 16 cm −3 ) Helium. The possibility of laser pulse peak intensity estimation in each shot in range from 10 18 to 10 20 W/cm 2 is demonstrated.